MPI4PY(1) MPI for Python MPI4PY(1)
NAME
mpi4py - MPI for Python
Author Lisandro Dalcin
Contact
dalcinl@gmail.com
Date March 16, 2022
Abstract
This document describes the MPI for Python package. MPI for Python pro-
vides Python bindings for the Message Passing Interface (MPI) standard,
allowing Python applications to exploit multiple processors on worksta-
tions, clusters and supercomputers.
This package builds on the MPI specification and provides an object
oriented interface resembling the MPI-2 C++ bindings. It supports
point-to-point (sends, receives) and collective (broadcasts, scatters,
gathers) communication of any picklable Python object, as well as effi-
cient communication of Python objects exposing the Python buffer inter-
face (e.g. NumPy arrays and builtin bytes/array/memoryview objects).
INTRODUCTION
Over the last years, high performance computing has become an afford-
able resource to many more researchers in the scientific community than
ever before. The conjunction of quality open source software and com-
modity hardware strongly influenced the now widespread popularity of
Beowulf class clusters and cluster of workstations.
Among many parallel computational models, message-passing has proven to
be an effective one. This paradigm is specially suited for (but not
limited to) distributed memory architectures and is used in today’s
most demanding scientific and engineering application related to model-
ing, simulation, design, and signal processing. However, portable mes-
sage-passing parallel programming used to be a nightmare in the past
because of the many incompatible options developers were faced to.
Fortunately, this situation definitely changed after the MPI Forum re-
leased its standard specification.
High performance computing is traditionally associated with software
development using compiled languages. However, in typical applications
programs, only a small part of the code is time-critical enough to re-
quire the efficiency of compiled languages. The rest of the code is
generally related to memory management, error handling, input/output,
and user interaction, and those are usually the most error prone and
time-consuming lines of code to write and debug in the whole develop-
ment process. Interpreted high-level languages can be really advanta-
geous for this kind of tasks.
For implementing general-purpose numerical computations, MATLAB [1] is
the dominant interpreted programming language. In the open source side,
Octave and Scilab are well known, freely distributed software packages
providing compatibility with the MATLAB language. In this work, we
present MPI for Python, a new package enabling applications to exploit
multiple processors using standard MPI “look and feel” in Python
scripts.
[1] MATLAB is a registered trademark of The MathWorks, Inc.
What is MPI?
MPI, [mpi-using] [mpi-ref] the Message Passing Interface, is a stan-
dardized and portable message-passing system designed to function on a
wide variety of parallel computers. The standard defines the syntax and
semantics of library routines and allows users to write portable pro-
grams in the main scientific programming languages (Fortran, C, or
C++).
Since its release, the MPI specification [mpi-std1] [mpi-std2] has be-
come the leading standard for message-passing libraries for parallel
computers. Implementations are available from vendors of high-perfor-
mance computers and from well known open source projects like MPICH
[mpi-mpich] and Open MPI [mpi-openmpi].
What is Python?
Python is a modern, easy to learn, powerful programming language. It
has efficient high-level data structures and a simple but effective ap-
proach to object-oriented programming with dynamic typing and dynamic
binding. It supports modules and packages, which encourages program
modularity and code reuse. Python’s elegant syntax, together with its
interpreted nature, make it an ideal language for scripting and rapid
application development in many areas on most platforms.
The Python interpreter and the extensive standard library are available
in source or binary form without charge for all major platforms, and
can be freely distributed. It is easily extended with new functions and
data types implemented in C or C++. Python is also suitable as an ex-
tension language for customizable applications.
Python is an ideal candidate for writing the higher-level parts of
large-scale scientific applications [Hinsen97] and driving simulations
in parallel architectures [Beazley97] like clusters of PC’s or SMP’s.
Python codes are quickly developed, easily maintained, and can achieve
a high degree of integration with other libraries written in compiled
languages.
Related Projects
As this work started and evolved, some ideas were borrowed from well
known MPI and Python related open source projects from the Internet.
• OOMPI
• It has no relation with Python, but is an excellent object oriented
approach to MPI.
• It is a C++ class library specification layered on top of the C
bindings that encapsulates MPI into a functional class hierarchy.
• It provides a flexible and intuitive interface by adding some ab-
stractions, like Ports and Messages, which enrich and simplify the
syntax.
• Pypar
• Its interface is rather minimal. There is no support for communica-
tors or process topologies.
• It does not require the Python interpreter to be modified or recom-
piled, but does not permit interactive parallel runs.
• General (picklable) Python objects of any type can be communicated.
There is good support for numeric arrays, practically full MPI
bandwidth can be achieved.
• pyMPI
• It rebuilds the Python interpreter providing a built-in module for
message passing. It does permit interactive parallel runs, which
are useful for learning and debugging.
• It provides an interface suitable for basic parallel programing.
There is not full support for defining new communicators or process
topologies.
• General (picklable) Python objects can be messaged between proces-
sors. There is not support for numeric arrays.
• Scientific Python
• It provides a collection of Python modules that are useful for sci-
entific computing.
• There is an interface to MPI and BSP (Bulk Synchronous Parallel
programming).
• The interface is simple but incomplete and does not resemble the
MPI specification. There is support for numeric arrays.
Additionally, we would like to mention some available tools for scien-
tific computing and software development with Python.
• NumPy is a package that provides array manipulation and computational
capabilities similar to those found in IDL, MATLAB, or Octave. Using
NumPy, it is possible to write many efficient numerical data process-
ing applications directly in Python without using any C, C++ or For-
tran code.
• SciPy is an open source library of scientific tools for Python, gath-
ering a variety of high level science and engineering modules to-
gether as a single package. It includes modules for graphics and
plotting, optimization, integration, special functions, signal and
image processing, genetic algorithms, ODE solvers, and others.
• Cython is a language that makes writing C extensions for the Python
language as easy as Python itself. The Cython language is very close
to the Python language, but Cython additionally supports calling C
functions and declaring C types on variables and class attributes.
This allows the compiler to generate very efficient C code from
Cython code. This makes Cython the ideal language for wrapping for
external C libraries, and for fast C modules that speed up the execu-
tion of Python code.
• SWIG is a software development tool that connects programs written in
C and C++ with a variety of high-level programming languages like
Perl, Tcl/Tk, Ruby and Python. Issuing header files to SWIG is the
simplest approach to interfacing C/C++ libraries from a Python mod-
ule.
[mpi-std1]
MPI Forum. MPI: A Message Passing Interface Standard. Interna-
tional Journal of Supercomputer Applications, volume 8, number
3-4, pages 159-416, 1994.
[mpi-std2]
MPI Forum. MPI: A Message Passing Interface Standard. High Per-
formance Computing Applications, volume 12, number 1-2, pages
1-299, 1998.
[mpi-using]
William Gropp, Ewing Lusk, and Anthony Skjellum. Using MPI: por-
table parallel programming with the message-passing interface.
MIT Press, 1994.
[mpi-ref]
Mark Snir, Steve Otto, Steven Huss-Lederman, David Walker, and
Jack Dongarra. MPI - The Complete Reference, volume 1, The MPI
Core. MIT Press, 2nd. edition, 1998.
[mpi-mpich]
W. Gropp, E. Lusk, N. Doss, and A. Skjellum. A high-performance,
portable implementation of the MPI message passing interface stan-
dard. Parallel Computing, 22(6):789-828, September 1996.
[mpi-openmpi]
Edgar Gabriel, Graham E. Fagg, George Bosilca, Thara Angskun, Jack
J. Dongarra, Jeffrey M. Squyres, Vishal Sahay, Prabhanjan Kam-
badur, Brian Barrett, Andrew Lumsdaine, Ralph H. Castain, David J.
Daniel, Richard L. Graham, and Timothy S. Woodall. Open MPI:
Goals, Concept, and Design of a Next Generation MPI Implementa-
tion. In Proceedings, 11th European PVM/MPI Users’ Group Meeting,
Budapest, Hungary, September 2004.
[Hinsen97]
Konrad Hinsen. The Molecular Modelling Toolkit: a case study of a
large scientific application in Python. In Proceedings of the 6th
International Python Conference, pages 29-35, San Jose, Ca., Octo-
ber 1997.
[Beazley97]
David M. Beazley and Peter S. Lomdahl. Feeding a large-scale
physics application to Python. In Proceedings of the 6th Interna-
tional Python Conference, pages 21-29, San Jose, Ca., October
1997.
OVERVIEW
MPI for Python provides an object oriented approach to message passing
which grounds on the standard MPI-2 C++ bindings. The interface was de-
signed with focus in translating MPI syntax and semantics of standard
MPI-2 bindings for C++ to Python. Any user of the standard C/C++ MPI
bindings should be able to use this module without need of learning a
new interface.
Communicating Python Objects and Array Data
The Python standard library supports different mechanisms for data per-
sistence. Many of them rely on disk storage, but pickling and marshal-
ing can also work with memory buffers.
The pickle modules provide user-extensible facilities to serialize gen-
eral Python objects using ASCII or binary formats. The marshal module
provides facilities to serialize built-in Python objects using a binary
format specific to Python, but independent of machine architecture is-
sues.
MPI for Python can communicate any built-in or user-defined Python ob-
ject taking advantage of the features provided by the pickle module.
These facilities will be routinely used to build binary representations
of objects to communicate (at sending processes), and restoring them
back (at receiving processes).
Although simple and general, the serialization approach (i.e., pickling
and unpickling) previously discussed imposes important overheads in
memory as well as processor usage, especially in the scenario of ob-
jects with large memory footprints being communicated. Pickling general
Python objects, ranging from primitive or container built-in types to
user-defined classes, necessarily requires computer resources. Pro-
cessing is also needed for dispatching the appropriate serialization
method (that depends on the type of the object) and doing the actual
packing. Additional memory is always needed, and if its total amount is
not known a priori, many reallocations can occur. Indeed, in the case
of large numeric arrays, this is certainly unacceptable and precludes
communication of objects occupying half or more of the available memory
resources.
MPI for Python supports direct communication of any object exporting
the single-segment buffer interface. This interface is a standard
Python mechanism provided by some types (e.g., strings and numeric ar-
rays), allowing access in the C side to a contiguous memory buffer
(i.e., address and length) containing the relevant data. This feature,
in conjunction with the capability of constructing user-defined MPI
datatypes describing complicated memory layouts, enables the implemen-
tation of many algorithms involving multidimensional numeric arrays
(e.g., image processing, fast Fourier transforms, finite difference
schemes on structured Cartesian grids) directly in Python, with negli-
gible overhead, and almost as fast as compiled Fortran, C, or C++
codes.
Communicators
In MPI for Python, Comm is the base class of communicators. The Intra-
comm and Intercomm classes are sublcasses of the Comm class. The
Comm.Is_inter method (and Comm.Is_intra, provided for convenience but
not part of the MPI specification) is defined for communicator objects
and can be used to determine the particular communicator class.
The two predefined intracommunicator instances are available: COMM_SELF
and COMM_WORLD. From them, new communicators can be created as needed.
The number of processes in a communicator and the calling process rank
can be respectively obtained with methods Comm.Get_size and
Comm.Get_rank. The associated process group can be retrieved from a
communicator by calling the Comm.Get_group method, which returns an in-
stance of the Group class. Set operations with Group objects like like
Group.Union, Group.Intersection and Group.Difference are fully sup-
ported, as well as the creation of new communicators from these groups
using Comm.Create and Comm.Create_group.
New communicator instances can be obtained with the Comm.Clone,
Comm.Dup and Comm.Split methods, as well methods Intracomm.Create_in-
tercomm and Intercomm.Merge.
Virtual topologies (Cartcomm, Graphcomm and Distgraphcomm classes,
which are specializations of the Intracomm class) are fully supported.
New instances can be obtained from intracommunicator instances with
factory methods Intracomm.Create_cart and Intracomm.Create_graph.
Point-to-Point Communications
Point to point communication is a fundamental capability of message
passing systems. This mechanism enables the transmission of data be-
tween a pair of processes, one side sending, the other receiving.
MPI provides a set of send and receive functions allowing the communi-
cation of typed data with an associated tag. The type information en-
ables the conversion of data representation from one architecture to
another in the case of heterogeneous computing environments; addition-
ally, it allows the representation of non-contiguous data layouts and
user-defined datatypes, thus avoiding the overhead of (otherwise un-
avoidable) packing/unpacking operations. The tag information allows se-
lectivity of messages at the receiving end.
Blocking Communications
MPI provides basic send and receive functions that are blocking. These
functions block the caller until the data buffers involved in the com-
munication can be safely reused by the application program.
In MPI for Python, the Comm.Send, Comm.Recv and Comm.Sendrecv methods
of communicator objects provide support for blocking point-to-point
communications within Intracomm and Intercomm instances. These methods
can communicate memory buffers. The variants Comm.send, Comm.recv and
Comm.sendrecv can communicate general Python objects.
Nonblocking Communications
On many systems, performance can be significantly increased by overlap-
ping communication and computation. This is particularly true on sys-
tems where communication can be executed autonomously by an intelli-
gent, dedicated communication controller.
MPI provides nonblocking send and receive functions. They allow the
possible overlap of communication and computation. Non-blocking commu-
nication always come in two parts: posting functions, which begin the
requested operation; and test-for-completion functions, which allow to
discover whether the requested operation has completed.
In MPI for Python, the Comm.Isend and Comm.Irecv methods initiate send
and receive operations, respectively. These methods return a Request
instance, uniquely identifying the started operation. Its completion
can be managed using the Request.Test, Request.Wait and Request.Cancel
methods. The management of Request objects and associated memory buf-
fers involved in communication requires a careful, rather low-level co-
ordination. Users must ensure that objects exposing their memory buf-
fers are not accessed at the Python level while they are involved in
nonblocking message-passing operations.
Persistent Communications
Often a communication with the same argument list is repeatedly exe-
cuted within an inner loop. In such cases, communication can be further
optimized by using persistent communication, a particular case of non-
blocking communication allowing the reduction of the overhead between
processes and communication controllers. Furthermore , this kind of op-
timization can also alleviate the extra call overheads associated to
interpreted, dynamic languages like Python.
In MPI for Python, the Comm.Send_init and Comm.Recv_init methods create
persistent requests for a send and receive operation, respectively.
These methods return an instance of the Prequest class, a subclass of
the Request class. The actual communication can be effectively started
using the Prequest.Start method, and its completion can be managed as
previously described.
Collective Communications
Collective communications allow the transmittal of data between multi-
ple processes of a group simultaneously. The syntax and semantics of
collective functions is consistent with point-to-point communication.
Collective functions communicate typed data, but messages are not
paired with an associated tag; selectivity of messages is implied in
the calling order. Additionally, collective functions come in blocking
versions only.
The more commonly used collective communication operations are the fol-
lowing.
• Barrier synchronization across all group members.
• Global communication functions
• Broadcast data from one member to all members of a group.
• Gather data from all members to one member of a group.
• Scatter data from one member to all members of a group.
• Global reduction operations such as sum, maximum, minimum, etc.
In MPI for Python, the Comm.Bcast, Comm.Scatter, Comm.Gather, Comm.All-
gather, Comm.Alltoall methods provide support for collective communica-
tions of memory buffers. The lower-case variants Comm.bcast, Comm.scat-
ter, Comm.gather, Comm.allgather and Comm.alltoall can communicate gen-
eral Python objects. The vector variants (which can communicate dif-
ferent amounts of data to each process) Comm.Scatterv, Comm.Gatherv,
Comm.Allgatherv, Comm.Alltoallv and Comm.Alltoallw are also supported,
they can only communicate objects exposing memory buffers.
Global reducion operations on memory buffers are accessible through the
Comm.Reduce, Comm.Reduce_scatter, Comm.Allreduce, Intracomm.Scan and
Intracomm.Exscan methods. The lower-case variants Comm.reduce,
Comm.allreduce, Intracomm.scan and Intracomm.exscan can communicate
general Python objects; however, the actual required reduction computa-
tions are performed sequentially at some process. All the predefined
(i.e., SUM, PROD, MAX, etc.) reduction operations can be applied.
Support for GPU-aware MPI
Several MPI implementations, including Open MPI and MVAPICH, support
passing GPU pointers to MPI calls to avoid explict data movement be-
tween the host and the device. On the Python side, GPU arrays have been
implemented by many libraries that need GPU computation, such as CuPy,
Numba, PyTorch, and PyArrow. In order to increase library interoper-
ability, two kinds of zero-copy data exchange protocols are defined and
agreed upon: DLPack and CUDA Array Interface. For example, a CuPy array
can be passed to a Numba CUDA-jit kernel.
MPI for Python provides an experimental support for GPU-aware MPI.
This feature requires:
1. mpi4py is built against a GPU-aware MPI library.
2. The Python GPU arrays are compliant with either of the protocols.
See the tutorial section for further information. We note that
• Whether or not a MPI call can work for GPU arrays depends on the un-
derlying MPI implementation, not on mpi4py.
• This support is currently experimental and subject to change in the
future.
Dynamic Process Management
In the context of the MPI-1 specification, a parallel application is
static; that is, no processes can be added to or deleted from a running
application after it has been started. Fortunately, this limitation was
addressed in MPI-2. The new specification added a process management
model providing a basic interface between an application and external
resources and process managers.
This MPI-2 extension can be really useful, especially for sequential
applications built on top of parallel modules, or parallel applications
with a client/server model. The MPI-2 process model provides a mecha-
nism to create new processes and establish communication between them
and the existing MPI application. It also provides mechanisms to estab-
lish communication between two existing MPI applications, even when one
did not start the other.
In MPI for Python, new independent process groups can be created by
calling the Intracomm.Spawn method within an intracommunicator. This
call returns a new intercommunicator (i.e., an Intercomm instance) at
the parent process group. The child process group can retrieve the
matching intercommunicator by calling the Comm.Get_parent class method.
At each side, the new intercommunicator can be used to perform point to
point and collective communications between the parent and child groups
of processes.
Alternatively, disjoint groups of processes can establish communication
using a client/server approach. Any server application must first call
the Open_port function to open a port and the Publish_name function to
publish a provided service, and next call the Intracomm.Accept method.
Any client applications can first find a published service by calling
the Lookup_name function, which returns the port where a server can be
contacted; and next call the Intracomm.Connect method. Both Intra-
comm.Accept and Intracomm.Connect methods return an Intercomm instance.
When connection between client/server processes is no longer needed,
all of them must cooperatively call the Comm.Disconnect method. Addi-
tionally, server applications should release resources by calling the
Unpublish_name and Close_port functions.
One-Sided Communications
One-sided communications (also called Remote Memory Access, RMA) sup-
plements the traditional two-sided, send/receive based MPI communica-
tion model with a one-sided, put/get based interface. One-sided commu-
nication that can take advantage of the capabilities of highly special-
ized network hardware. Additionally, this extension lowers latency and
software overhead in applications written using a shared-memory-like
paradigm.
The MPI specification revolves around the use of objects called win-
dows; they intuitively specify regions of a process’s memory that have
been made available for remote read and write operations. The pub-
lished memory blocks can be accessed through three functions for put
(remote send), get (remote write), and accumulate (remote update or re-
duction) data items. A much larger number of functions support differ-
ent synchronization styles; the semantics of these synchronization op-
erations are fairly complex.
In MPI for Python, one-sided operations are available by using in-
stances of the Win class. New window objects are created by calling the
Win.Create method at all processes within a communicator and specifying
a memory buffer . When a window instance is no longer needed, the
Win.Free method should be called.
The three one-sided MPI operations for remote write, read and reduction
are available through calling the methods Win.Put, Win.Get, and Win.Ac-
cumulate respectively within a Win instance. These methods need an in-
teger rank identifying the target process and an integer offset rela-
tive the base address of the remote memory block being accessed.
The one-sided operations read, write, and reduction are implicitly non-
blocking, and must be synchronized by using two primary modes. Active
target synchronization requires the origin process to call the
Win.Start and Win.Complete methods at the origin process, and target
process cooperates by calling the Win.Post and Win.Wait methods. There
is also a collective variant provided by the Win.Fence method. Passive
target synchronization is more lenient, only the origin process calls
the Win.Lock and Win.Unlock methods. Locks are used to protect remote
accesses to the locked remote window and to protect local load/store
accesses to a locked local window.
Parallel Input/Output
The POSIX standard provides a model of a widely portable file system.
However, the optimization needed for parallel input/output cannot be
achieved with this generic interface. In order to ensure efficiency and
scalability, the underlying parallel input/output system must provide a
high-level interface supporting partitioning of file data among pro-
cesses and a collective interface supporting complete transfers of
global data structures between process memories and files. Addition-
ally, further efficiencies can be gained via support for asynchronous
input/output, strided accesses to data, and control over physical file
layout on storage devices. This scenario motivated the inclusion in the
MPI-2 standard of a custom interface in order to support more elabo-
rated parallel input/output operations.
The MPI specification for parallel input/output revolves around the use
objects called files. As defined by MPI, files are not just contiguous
byte streams. Instead, they are regarded as ordered collections of
typed data items. MPI supports sequential or random access to any inte-
gral set of these items. Furthermore, files are opened collectively by
a group of processes.
The common patterns for accessing a shared file (broadcast, scatter,
gather, reduction) is expressed by using user-defined datatypes. Com-
pared to the communication patterns of point-to-point and collective
communications, this approach has the advantage of added flexibility
and expressiveness. Data access operations (read and write) are defined
for different kinds of positioning (using explicit offsets, individual
file pointers, and shared file pointers), coordination (non-collective
and collective), and synchronism (blocking, nonblocking, and split col-
lective with begin/end phases).
In MPI for Python, all MPI input/output operations are performed
through instances of the File class. File handles are obtained by call-
ing the File.Open method at all processes within a communicator and
providing a file name and the intended access mode. After use, they
must be closed by calling the File.Close method. Files even can be
deleted by calling method File.Delete.
After creation, files are typically associated with a per-process view.
The view defines the current set of data visible and accessible from an
open file as an ordered set of elementary datatypes. This data layout
can be set and queried with the File.Set_view and File.Get_view methods
respectively.
Actual input/output operations are achieved by many methods combining
read and write calls with different behavior regarding positioning, co-
ordination, and synchronism. Summing up, MPI for Python provides the
thirty (30) methods defined in MPI-2 for reading from or writing to
files using explicit offsets or file pointers (individual or shared),
in blocking or nonblocking and collective or noncollective versions.
Environmental Management
Initialization and Exit
Module functions Init or Init_thread and Finalize provide MPI initial-
ization and finalization respectively. Module functions Is_initialized
and Is_finalized provide the respective tests for initialization and
finalization.
NOTE:
MPI_Init() or MPI_Init_thread() is actually called when you import
the MPI module from the mpi4py package, but only if MPI is not al-
ready initialized. In such case, calling Init or Init_thread from
Python is expected to generate an MPI error, and in turn an excep-
tion will be raised.
NOTE:
MPI_Finalize() is registered (by using Python C/API function
Py_AtExit()) for being automatically called when Python processes
exit, but only if mpi4py actually initialized MPI. Therefore, there
is no need to call Finalize from Python to ensure MPI finalization.
Implementation Information
• The MPI version number can be retrieved from module function Get_ver-
sion. It returns a two-integer tuple (version, subversion).
• The Get_processor_name function can be used to access the processor
name.
• The values of predefined attributes attached to the world communica-
tor can be obtained by calling the Comm.Get_attr method within the
COMM_WORLD instance.
Timers
MPI timer functionalities are available through the Wtime and Wtick
functions.
Error Handling
In order facilitate handle sharing with other Python modules interfac-
ing MPI-based parallel libraries, the predefined MPI error handlers ER-
RORS_RETURN and ERRORS_ARE_FATAL can be assigned to and retrieved from
communicators using methods Comm.Set_errhandler and Comm.Get_errhan-
dler, and similarly for windows and files.
When the predefined error handler ERRORS_RETURN is set, errors returned
from MPI calls within Python code will raise an instance of the excep-
tion class Exception, which is a subclass of the standard Python excep-
tion python:RuntimeError.
NOTE:
After import, mpi4py overrides the default MPI rules governing in-
heritance of error handlers. The ERRORS_RETURN error handler is set
in the predefined COMM_SELF and COMM_WORLD communicators, as well as
any new Comm, Win, or File instance created through mpi4py. If you
ever pass such handles to C/C++/Fortran library code, it is recom-
mended to set the ERRORS_ARE_FATAL error handler on them to ensure
MPI errors do not pass silently.
WARNING:
Importing with from mpi4py.MPI import * will cause a name clashing
with the standard Python python:Exception base class.
TUTORIAL
WARNING:
Under construction. Contributions very welcome!
TIP:
Rolf Rabenseifner at HLRS developed a comprehensive MPI-3.1/4.0
course with slides and a large set of exercises including solutions.
This material is available online for self-study. The slides and ex-
ercises show the C, Fortran, and Python (mpi4py) interfaces. For
performance reasons, most Python exercises use NumPy arrays and com-
munication routines involving buffer-like objects.
TIP:
Victor Eijkhout at TACC authored the book Parallel Programming for
Science and Engineering. This book is available online in PDF and
HTML formats. The book covers parallel programming with MPI and
OpenMP in C/C++ and Fortran, and MPI in Python using mpi4py.
MPI for Python supports convenient, pickle-based communication of
generic Python object as well as fast, near C-speed, direct array data
communication of buffer-provider objects (e.g., NumPy arrays).
• Communication of generic Python objects
You have to use methods with all-lowercase names, like Comm.send,
Comm.recv, Comm.bcast, Comm.scatter, Comm.gather . An object to be
sent is passed as a parameter to the communication call, and the re-
ceived object is simply the return value.
The Comm.isend and Comm.irecv methods return Request instances; com-
pletion of these methods can be managed using the Request.test and
Request.wait methods.
The Comm.recv and Comm.irecv methods may be passed a buffer object
that can be repeatedly used to receive messages avoiding internal
memory allocation. This buffer must be sufficiently large to accommo-
date the transmitted messages; hence, any buffer passed to Comm.recv
or Comm.irecv must be at least as long as the pickled data transmit-
ted to the receiver.
Collective calls like Comm.scatter, Comm.gather, Comm.allgather,
Comm.alltoall expect a single value or a sequence of Comm.size ele-
ments at the root or all process. They return a single value, a list
of Comm.size elements, or None.
NOTE:
MPI for Python uses the highest protocol version available in the
Python runtime (see the HIGHEST_PROTOCOL constant in the pickle
module). The default protocol can be changed at import time by
setting the MPI4PY_PICKLE_PROTOCOL environment variable, or at
runtime by assigning a different value to the PROTOCOL attribute
of the pickle object within the MPI module.
• Communication of buffer-like objects
You have to use method names starting with an upper-case letter, like
Comm.Send, Comm.Recv, Comm.Bcast, Comm.Scatter, Comm.Gather.
In general, buffer arguments to these calls must be explicitly speci-
fied by using a 2/3-list/tuple like [data, MPI.DOUBLE], or [data,
count, MPI.DOUBLE] (the former one uses the byte-size of data and the
extent of the MPI datatype to define count).
For vector collectives communication operations like Comm.Scatterv
and Comm.Gatherv, buffer arguments are specified as [data, count,
displ, datatype], where count and displ are sequences of integral
values.
Automatic MPI datatype discovery for NumPy/GPU arrays and PEP-3118
buffers is supported, but limited to basic C types (all C/C99-native
signed/unsigned integral types and single/double precision real/com-
plex floating types) and availability of matching datatypes in the
underlying MPI implementation. In this case, the buffer-provider ob-
ject can be passed directly as a buffer argument, the count and MPI
datatype will be inferred.
If mpi4py is built against a GPU-aware MPI implementation, GPU arrays
can be passed to upper-case methods as long as they have either the
__dlpack__ and __dlpack_device__ methods or the __cuda_array_inter-
face__ attribute that are compliant with the respective standard
specifications. Moreover, only C-contiguous or Fortran-contiguous GPU
arrays are supported. It is important to note that GPU buffers must
be fully ready before any MPI routines operate on them to avoid race
conditions. This can be ensured by using the synchronization API of
your array library. mpi4py does not have access to any GPU-specific
functionality and thus cannot perform this operation automatically
for users.
Running Python scripts with MPI
Most MPI programs can be run with the command mpiexec. In practice,
running Python programs looks like:
$ mpiexec -n 4 python script.py
to run the program with 4 processors.
Point-to-Point Communication
• Python objects (pickle under the hood):
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = {'a': 7, 'b': 3.14}
comm.send(data, dest=1, tag=11)
elif rank == 1:
data = comm.recv(source=0, tag=11)
• Python objects with non-blocking communication:
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = {'a': 7, 'b': 3.14}
req = comm.isend(data, dest=1, tag=11)
req.wait()
elif rank == 1:
req = comm.irecv(source=0, tag=11)
data = req.wait()
• NumPy arrays (the fast way!):
from mpi4py import MPI
import numpy
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
# passing MPI datatypes explicitly
if rank == 0:
data = numpy.arange(1000, dtype='i')
comm.Send([data, MPI.INT], dest=1, tag=77)
elif rank == 1:
data = numpy.empty(1000, dtype='i')
comm.Recv([data, MPI.INT], source=0, tag=77)
# automatic MPI datatype discovery
if rank == 0:
data = numpy.arange(100, dtype=numpy.float64)
comm.Send(data, dest=1, tag=13)
elif rank == 1:
data = numpy.empty(100, dtype=numpy.float64)
comm.Recv(data, source=0, tag=13)
Collective Communication
• Broadcasting a Python dictionary:
from mpi4py import MPI
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = {'key1' : [7, 2.72, 2+3j],
'key2' : ( 'abc', 'xyz')}
else:
data = None
data = comm.bcast(data, root=0)
• Scattering Python objects:
from mpi4py import MPI
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
if rank == 0:
data = [(i+1)**2 for i in range(size)]
else:
data = None
data = comm.scatter(data, root=0)
assert data == (rank+1)**2
• Gathering Python objects:
from mpi4py import MPI
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
data = (rank+1)**2
data = comm.gather(data, root=0)
if rank == 0:
for i in range(size):
assert data[i] == (i+1)**2
else:
assert data is None
• Broadcasting a NumPy array:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
if rank == 0:
data = np.arange(100, dtype='i')
else:
data = np.empty(100, dtype='i')
comm.Bcast(data, root=0)
for i in range(100):
assert data[i] == i
• Scattering NumPy arrays:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
sendbuf = None
if rank == 0:
sendbuf = np.empty([size, 100], dtype='i')
sendbuf.T[:,:] = range(size)
recvbuf = np.empty(100, dtype='i')
comm.Scatter(sendbuf, recvbuf, root=0)
assert np.allclose(recvbuf, rank)
• Gathering NumPy arrays:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
sendbuf = np.zeros(100, dtype='i') + rank
recvbuf = None
if rank == 0:
recvbuf = np.empty([size, 100], dtype='i')
comm.Gather(sendbuf, recvbuf, root=0)
if rank == 0:
for i in range(size):
assert np.allclose(recvbuf[i,:], i)
• Parallel matrix-vector product:
from mpi4py import MPI
import numpy
def matvec(comm, A, x):
m = A.shape[0] # local rows
p = comm.Get_size()
xg = numpy.zeros(m*p, dtype='d')
comm.Allgather([x, MPI.DOUBLE],
[xg, MPI.DOUBLE])
y = numpy.dot(A, xg)
return y
MPI-IO
• Collective I/O with NumPy arrays:
from mpi4py import MPI
import numpy as np
amode = MPI.MODE_WRONLY|MPI.MODE_CREATE
comm = MPI.COMM_WORLD
fh = MPI.File.Open(comm, "./datafile.contig", amode)
buffer = np.empty(10, dtype=np.int)
buffer[:] = comm.Get_rank()
offset = comm.Get_rank()*buffer.nbytes
fh.Write_at_all(offset, buffer)
fh.Close()
• Non-contiguous Collective I/O with NumPy arrays and datatypes:
from mpi4py import MPI
import numpy as np
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
size = comm.Get_size()
amode = MPI.MODE_WRONLY|MPI.MODE_CREATE
fh = MPI.File.Open(comm, "./datafile.noncontig", amode)
item_count = 10
buffer = np.empty(item_count, dtype='i')
buffer[:] = rank
filetype = MPI.INT.Create_vector(item_count, 1, size)
filetype.Commit()
displacement = MPI.INT.Get_size()*rank
fh.Set_view(displacement, filetype=filetype)
fh.Write_all(buffer)
filetype.Free()
fh.Close()
Dynamic Process Management
• Compute Pi - Master (or parent, or client) side:
#!/usr/bin/env python
from mpi4py import MPI
import numpy
import sys
comm = MPI.COMM_SELF.Spawn(sys.executable,
args=['cpi.py'],
maxprocs=5)
N = numpy.array(100, 'i')
comm.Bcast([N, MPI.INT], root=MPI.ROOT)
PI = numpy.array(0.0, 'd')
comm.Reduce(None, [PI, MPI.DOUBLE],
op=MPI.SUM, root=MPI.ROOT)
print(PI)
comm.Disconnect()
• Compute Pi - Worker (or child, or server) side:
#!/usr/bin/env python
from mpi4py import MPI
import numpy
comm = MPI.Comm.Get_parent()
size = comm.Get_size()
rank = comm.Get_rank()
N = numpy.array(0, dtype='i')
comm.Bcast([N, MPI.INT], root=0)
h = 1.0 / N; s = 0.0
for i in range(rank, N, size):
x = h * (i + 0.5)
s += 4.0 / (1.0 + x**2)
PI = numpy.array(s * h, dtype='d')
comm.Reduce([PI, MPI.DOUBLE], None,
op=MPI.SUM, root=0)
comm.Disconnect()
CUDA-aware MPI + Python GPU arrays
• Reduce-to-all CuPy arrays:
from mpi4py import MPI
import cupy as cp
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
sendbuf = cp.arange(10, dtype='i')
recvbuf = cp.empty_like(sendbuf)
assert hasattr(sendbuf, '__cuda_array_interface__')
assert hasattr(recvbuf, '__cuda_array_interface__')
cp.cuda.get_current_stream().synchronize()
comm.Allreduce(sendbuf, recvbuf)
assert cp.allclose(recvbuf, sendbuf*size)
One-Sided Communications
• Read from (write to) the entire RMA window:
import numpy as np
from mpi4py import MPI
from mpi4py.util import dtlib
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
datatype = MPI.FLOAT
np_dtype = dtlib.to_numpy_dtype(datatype)
itemsize = datatype.Get_size()
N = 10
win_size = N * itemsize if rank == 0 else 0
win = MPI.Win.Allocate(win_size, comm=comm)
buf = np.empty(N, dtype=np_dtype)
if rank == 0:
buf.fill(42)
win.Lock(rank=0)
win.Put(buf, target_rank=0)
win.Unlock(rank=0)
comm.Barrier()
else:
comm.Barrier()
win.Lock(rank=0)
win.Get(buf, target_rank=0)
win.Unlock(rank=0)
assert np.all(buf == 42)
• Accessing a part of the RMA window using the target argument, which
is defined as (offset, count, datatype):
import numpy as np
from mpi4py import MPI
from mpi4py.util import dtlib
comm = MPI.COMM_WORLD
rank = comm.Get_rank()
datatype = MPI.FLOAT
np_dtype = dtlib.to_numpy_dtype(datatype)
itemsize = datatype.Get_size()
N = comm.Get_size() + 1
win_size = N * itemsize if rank == 0 else 0
win = MPI.Win.Allocate(
size=win_size,
disp_unit=itemsize,
comm=comm,
)
if rank == 0:
mem = np.frombuffer(win, dtype=np_dtype)
mem[:] = np.arange(len(mem), dtype=np_dtype)
comm.Barrier()
buf = np.zeros(3, dtype=np_dtype)
target = (rank, 2, datatype)
win.Lock(rank=0)
win.Get(buf, target_rank=0, target=target)
win.Unlock(rank=0)
assert np.all(buf == [rank, rank+1, 0])
Wrapping with SWIG
• C source:
/* file: helloworld.c */
void sayhello(MPI_Comm comm)
{
int size, rank;
MPI_Comm_size(comm, &size);
MPI_Comm_rank(comm, &rank);
printf("Hello, World! "
"I am process %d of %d.\n",
rank, size);
}
• SWIG interface file:
// file: helloworld.i
%module helloworld
%{
#include <mpi.h>
#include "helloworld.c"
}%
%include mpi4py/mpi4py.i
%mpi4py_typemap(Comm, MPI_Comm);
void sayhello(MPI_Comm comm);
• Try it in the Python prompt:
>>> from mpi4py import MPI
>>> import helloworld
>>> helloworld.sayhello(MPI.COMM_WORLD)
Hello, World! I am process 0 of 1.
Wrapping with F2Py
• Fortran 90 source:
! file: helloworld.f90
subroutine sayhello(comm)
use mpi
implicit none
integer :: comm, rank, size, ierr
call MPI_Comm_size(comm, size, ierr)
call MPI_Comm_rank(comm, rank, ierr)
print *, 'Hello, World! I am process ',rank,' of ',size,'.'
end subroutine sayhello
• Compiling example using f2py
$ f2py -c --f90exec=mpif90 helloworld.f90 -m helloworld
• Try it in the Python prompt:
>>> from mpi4py import MPI
>>> import helloworld
>>> fcomm = MPI.COMM_WORLD.py2f()
>>> helloworld.sayhello(fcomm)
Hello, World! I am process 0 of 1.
MPI4PY
This is the MPI for Python package.
The Message Passing Interface (MPI) is a standardized and portable mes-
sage-passing system designed to function on a wide variety of parallel
computers. The MPI standard defines the syntax and semantics of library
routines and allows users to write portable programs in the main scien-
tific programming languages (Fortran, C, or C++). Since its release,
the MPI specification has become the leading standard for message-pass-
ing libraries for parallel computers.
MPI for Python provides MPI bindings for the Python programming lan-
guage, allowing any Python program to exploit multiple processors.
This package build on the MPI specification and provides an object ori-
ented interface which closely follows MPI-2 C++ bindings.
Runtime configuration options
mpi4py.rc
This object has attributes exposing runtime configuration op-
tions that become effective at import time of the MPI module.
Attributes Summary
┌─────────────┬────────────────────────────┐
│initialize │ Automatic MPI initializa- │
│ │ tion at import │
├─────────────┼────────────────────────────┤
│threads │ Request initialization │
│ │ with thread support │
├─────────────┼────────────────────────────┤
│thread_level │ Level of thread support to │
│ │ request │
└─────────────┴────────────────────────────┘
│finalize │ Automatic MPI finalization │
│ │ at exit │
├─────────────┼────────────────────────────┤
│fast_reduce │ Use tree-based reductions │
│ │ for objects │
├─────────────┼────────────────────────────┤
│recv_mprobe │ Use matched probes to re- │
│ │ ceive objects │
├─────────────┼────────────────────────────┤
│errors │ Error handling policy │
└─────────────┴────────────────────────────┘
Attributes Documentation
mpi4py.rc.initialize
Automatic MPI initialization at import.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_INITIALIZE
mpi4py.rc.threads
Request initialization with thread support.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_THREADS
mpi4py.rc.thread_level
Level of thread support to request.
Type str
Default
"multiple"
Choices
"multiple", "serialized", "funneled", "single"
SEE ALSO:
MPI4PY_RC_THREAD_LEVEL
mpi4py.rc.finalize
Automatic MPI finalization at exit.
Type None or bool
Default
None
SEE ALSO:
MPI4PY_RC_FINALIZE
mpi4py.rc.fast_reduce
Use tree-based reductions for objects.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_FAST_REDUCE
mpi4py.rc.recv_mprobe
Use matched probes to receive objects.
Type bool
Default
True
SEE ALSO:
MPI4PY_RC_RECV_MPROBE
mpi4py.rc.errors
Error handling policy.
Type str
Default
"exception"
Choices
"exception", "default", "fatal"
SEE ALSO:
MPI4PY_RC_ERRORS
Example
MPI for Python features automatic initialization and finalization of
the MPI execution environment. By using the mpi4py.rc object, MPI ini-
tialization and finalization can be handled programatically:
import mpi4py
mpi4py.rc.initialize = False # do not initialize MPI automatically
mpi4py.rc.finalize = False # do not finalize MPI automatically
from mpi4py import MPI # import the 'MPI' module
MPI.Init() # manual initialization of the MPI environment
... # your finest code here ...
MPI.Finalize() # manual finalization of the MPI environment
Environment variables
The following environment variables override the corresponding at-
tributes of the mpi4py.rc and MPI.pickle objects at import time of the
MPI module.
NOTE:
For variables of boolean type, accepted values are 0 and 1 (inter-
preted as False and True, respectively), and strings specifying a
YAML boolean value (case-insensitive).
MPI4PY_RC_INITIALIZE
Type bool
Default
True
Whether to automatically initialize MPI at import time of the
mpi4py.MPI module.
SEE ALSO:
mpi4py.rc.initialize
New in version 3.1.0.
MPI4PY_RC_FINALIZE
Type None | bool
Default
None
Choices
None, True, False
Whether to automatically finalize MPI at exit time of the Python
process.
SEE ALSO:
mpi4py.rc.finalize
New in version 3.1.0.
MPI4PY_RC_THREADS
Type bool
Default
True
Whether to initialize MPI with thread support.
SEE ALSO:
mpi4py.rc.threads
New in version 3.1.0.
MPI4PY_RC_THREAD_LEVEL
Default
"multiple"
Choices
"single", "funneled", "serialized", "multiple"
The level of required thread support.
SEE ALSO:
mpi4py.rc.thread_level
New in version 3.1.0.
MPI4PY_RC_FAST_REDUCE
Type bool
Default
True
Whether to use tree-based reductions for objects.
SEE ALSO:
mpi4py.rc.fast_reduce
New in version 3.1.0.
MPI4PY_RC_RECV_MPROBE
Type bool
Default
True
Whether to use matched probes to receive objects.
SEE ALSO:
mpi4py.rc.recv_mprobe
MPI4PY_RC_ERRORS
Default
"exception"
Choices
"exception", "default", "fatal"
Controls default MPI error handling policy.
SEE ALSO:
mpi4py.rc.errors
New in version 3.1.0.
MPI4PY_PICKLE_PROTOCOL
Type int
Default
pickle.HIGHEST_PROTOCOL
Controls the default pickle protocol to use when communicating
Python objects.
SEE ALSO:
PROTOCOL attribute of the MPI.pickle object within the MPI
module.
New in version 3.1.0.
MPI4PY_PICKLE_THRESHOLD
Type int
Default
262144
Controls the default buffer size threshold for switching from
in-band to out-of-band buffer handling when using pickle proto-
col version 5 or higher.
SEE ALSO:
Module mpi4py.util.pkl5.
New in version 3.1.2.
Miscellaneous functions
mpi4py.profile(name, *, path=None, logfile=None)
Support for the MPI profiling interface.
Parameters
• name (str) – Name of the profiler library to load.
• path (sequence of str, optional) – Additional paths to
search for the profiler.
• logfile (str, optional) – Filename prefix for dumping
profiler output.
Return type
None
mpi4py.get_config()
Return a dictionary with information about MPI.
Return type
Dict[str, str]
mpi4py.get_include()
Return the directory in the package that contains header files.
Extension modules that need to compile against mpi4py should use
this function to locate the appropriate include directory. Using
Python distutils (or perhaps NumPy distutils):
import mpi4py
Extension('extension_name', ...
include_dirs=[..., mpi4py.get_include()])
Return type
str
MPI4PY.MPI
Classes
Ancillary
┌─────────────────────┬────────────────────────────┐
│Datatype([datatype]) │ Datatype object │
├─────────────────────┼────────────────────────────┤
│Status([status]) │ Status object │
├─────────────────────┼────────────────────────────┤
│Request([request]) │ Request handle │
├─────────────────────┼────────────────────────────┤
│Prequest([request]) │ Persistent request handle │
├─────────────────────┼────────────────────────────┤
│Grequest([request]) │ Generalized request handle │
├─────────────────────┼────────────────────────────┤
│Op([op]) │ Operation object │
├─────────────────────┼────────────────────────────┤
│Group([group]) │ Group of processes │
├─────────────────────┼────────────────────────────┤
│Info([info]) │ Info object │
└─────────────────────┴────────────────────────────┘
Communication
┌──────────────────────┬────────────────────────────┐
│Comm([comm]) │ Communicator │
├──────────────────────┼────────────────────────────┤
│Intracomm([comm]) │ Intracommunicator │
├──────────────────────┼────────────────────────────┤
│Topocomm([comm]) │ Topology intracommunicator │
├──────────────────────┼────────────────────────────┤
│Cartcomm([comm]) │ Cartesian topology intra- │
│ │ communicator │
├──────────────────────┼────────────────────────────┤
│Graphcomm([comm]) │ General graph topology in- │
│ │ tracommunicator │
├──────────────────────┼────────────────────────────┤
│Distgraphcomm([comm]) │ Distributed graph topology │
│ │ intracommunicator │
├──────────────────────┼────────────────────────────┤
│Intercomm([comm]) │ Intercommunicator │
├──────────────────────┼────────────────────────────┤
│Message([message]) │ Matched message handle │
└──────────────────────┴────────────────────────────┘
One-sided operations
┌───────────┬───────────────┐
│Win([win]) │ Window handle │
└───────────┴───────────────┘
Input/Output
┌─────────────┬─────────────┐
│File([file]) │ File handle │
└─────────────┴─────────────┘
Error handling
┌─────────────────────────┬─────────────────┐
│Errhandler([errhandler]) │ Error handler │
├─────────────────────────┼─────────────────┤
│Exception([ierr]) │ Exception class │
└─────────────────────────┴─────────────────┘
Auxiliary
┌───────────────────────────┬────────────────────────────┐
│Pickle([dumps, loads, pro- │ Pickle/unpickle Python ob- │
│tocol]) │ jects │
├───────────────────────────┼────────────────────────────┤
│memory(buf) │ Memory buffer │
└───────────────────────────┴────────────────────────────┘
Functions
Version inquiry
┌──────────────────────┬────────────────────────────┐
│Get_version() │ Obtain the version number │
│ │ of the MPI standard sup- │
│ │ ported by the implementa- │
│ │ tion as a tuple (version, │
│ │ subversion) │
├──────────────────────┼────────────────────────────┤
│Get_library_version() │ Obtain the version string │
│ │ of the MPI library │
└──────────────────────┴────────────────────────────┘
Initialization and finalization
┌────────────────────────┬────────────────────────────┐
│Init() │ Initialize the MPI execu- │
│ │ tion environment │
├────────────────────────┼────────────────────────────┤
│Init_thread([required]) │ Initialize the MPI execu- │
│ │ tion environment │
├────────────────────────┼────────────────────────────┤
│Finalize() │ Terminate the MPI execu- │
│ │ tion environment │
├────────────────────────┼────────────────────────────┤
│Is_initialized() │ Indicates whether Init has │
│ │ been called │
├────────────────────────┼────────────────────────────┤
│Is_finalized() │ Indicates whether Finalize │
│ │ has completed │
├────────────────────────┼────────────────────────────┤
│Query_thread() │ Return the level of thread │
│ │ support provided by the │
│ │ MPI library │
├────────────────────────┼────────────────────────────┤
│Is_thread_main() │ Indicate whether this │
│ │ thread called Init or │
│ │ Init_thread │
└────────────────────────┴────────────────────────────┘
Memory allocation
┌────────────────────────┬────────────────────────────┐
│Alloc_mem(size[, info]) │ Allocate memory for mes- │
│ │ sage passing and RMA │
├────────────────────────┼────────────────────────────┤
│Free_mem(mem) │ Free memory allocated with │
│ │ Alloc_mem() │
└────────────────────────┴────────────────────────────┘
Address manipulation
┌────────────────────────┬────────────────────────────┐
│Get_address(location) │ Get the address of a loca- │
│ │ tion in memory │
├────────────────────────┼────────────────────────────┤
│Aint_add(base, disp) │ Return the sum of base ad- │
│ │ dress and displacement │
├────────────────────────┼────────────────────────────┤
│Aint_diff(addr1, addr2) │ Return the difference be- │
│ │ tween absolute addresses │
└────────────────────────┴────────────────────────────┘
Timer
┌────────┬────────────────────────────┐
│Wtick() │ Return the resolution of │
│ │ Wtime │
├────────┼────────────────────────────┤
│Wtime() │ Return an elapsed time on │
│ │ the calling processor │
└────────┴────────────────────────────┘
Error handling
┌───────────────────────────┬────────────────────────────┐
│Get_error_class(errorcode) │ Convert an error code into │
│ │ an error class │
├───────────────────────────┼────────────────────────────┤
│Get_error_string(error- │ Return the error string │
│code) │ for a given error class or │
│ │ error code │
├───────────────────────────┼────────────────────────────┤
│Add_error_class() │ Add an error class to the │
│ │ known error classes │
├───────────────────────────┼────────────────────────────┤
│Add_error_code(errorclass) │ Add an error code to an │
│ │ error class │
├───────────────────────────┼────────────────────────────┤
│Add_error_string(error- │ Associate an error string │
│code, string) │ with an error class or er- │
│ │ rorcode │
└───────────────────────────┴────────────────────────────┘
Dynamic process management
┌───────────────────────────┬────────────────────────────┐
│Open_port([info]) │ Return an address that can │
│ │ be used to establish con- │
│ │ nections between groups of │
│ │ MPI processes │
├───────────────────────────┼────────────────────────────┤
│Close_port(port_name) │ Close a port │
├───────────────────────────┼────────────────────────────┤
│Publish_name(service_name, │ Publish a service name │
│port_name[, info]) │ │
├───────────────────────────┼────────────────────────────┤
│Unpublish_name(ser- │ Unpublish a service name │
│vice_name, port_name[, │ │
│info]) │ │
└───────────────────────────┴────────────────────────────┘
│Lookup_name(service_name[, │ Lookup a port name given a │
│info]) │ service name │
└───────────────────────────┴────────────────────────────┘
Miscellanea
┌───────────────────────────┬────────────────────────────┐
│Attach_buffer(buf) │ Attach a user-provided │
│ │ buffer for sending in │
│ │ buffered mode │
├───────────────────────────┼────────────────────────────┤
│Detach_buffer() │ Remove an existing at- │
│ │ tached buffer │
├───────────────────────────┼────────────────────────────┤
│Compute_dims(nnodes, dims) │ Return a balanced distri- │
│ │ bution of processes per │
│ │ coordinate direction │
├───────────────────────────┼────────────────────────────┤
│Get_processor_name() │ Obtain the name of the │
│ │ calling processor │
├───────────────────────────┼────────────────────────────┤
│Register_datarep(datarep, │ Register user-defined data │
│read_fn, write_fn, ...) │ representations │
├───────────────────────────┼────────────────────────────┤
│Pcontrol(level) │ Control profiling │
└───────────────────────────┴────────────────────────────┘
Utilities
┌─────────────┬────────────────────────────┐
│get_vendor() │ Infomation about the un- │
│ │ derlying MPI implementa- │
│ │ tion │
└─────────────┴────────────────────────────┘
Attributes
┌───────────────────────────┬────────────────────────────┐
│UNDEFINED │ int UNDEFINED │
├───────────────────────────┼────────────────────────────┤
│ANY_SOURCE │ int ANY_SOURCE │
├───────────────────────────┼────────────────────────────┤
│ANY_TAG │ int ANY_TAG │
├───────────────────────────┼────────────────────────────┤
│PROC_NULL │ int PROC_NULL │
├───────────────────────────┼────────────────────────────┤
│ROOT │ int ROOT │
├───────────────────────────┼────────────────────────────┤
│BOTTOM │ Bottom BOTTOM │
├───────────────────────────┼────────────────────────────┤
│IN_PLACE │ InPlace IN_PLACE │
├───────────────────────────┼────────────────────────────┤
│KEYVAL_INVALID │ int KEYVAL_INVALID │
├───────────────────────────┼────────────────────────────┤
│TAG_UB │ int TAG_UB │
├───────────────────────────┼────────────────────────────┤
│HOST │ int HOST │
├───────────────────────────┼────────────────────────────┤
│IO │ int IO │
├───────────────────────────┼────────────────────────────┤
│WTIME_IS_GLOBAL │ int WTIME_IS_GLOBAL │
├───────────────────────────┼────────────────────────────┤
│UNIVERSE_SIZE │ int UNIVERSE_SIZE │
├───────────────────────────┼────────────────────────────┤
│APPNUM │ int APPNUM │
├───────────────────────────┼────────────────────────────┤
│LASTUSEDCODE │ int LASTUSEDCODE │
├───────────────────────────┼────────────────────────────┤
│WIN_BASE │ int WIN_BASE │
└───────────────────────────┴────────────────────────────┘
│WIN_SIZE │ int WIN_SIZE │
├───────────────────────────┼────────────────────────────┤
│WIN_DISP_UNIT │ int WIN_DISP_UNIT │
├───────────────────────────┼────────────────────────────┤
│WIN_CREATE_FLAVOR │ int WIN_CREATE_FLAVOR │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR │ int WIN_FLAVOR │
├───────────────────────────┼────────────────────────────┤
│WIN_MODEL │ int WIN_MODEL │
├───────────────────────────┼────────────────────────────┤
│SUCCESS │ int SUCCESS │
├───────────────────────────┼────────────────────────────┤
│ERR_LASTCODE │ int ERR_LASTCODE │
├───────────────────────────┼────────────────────────────┤
│ERR_COMM │ int ERR_COMM │
├───────────────────────────┼────────────────────────────┤
│ERR_GROUP │ int ERR_GROUP │
├───────────────────────────┼────────────────────────────┤
│ERR_TYPE │ int ERR_TYPE │
├───────────────────────────┼────────────────────────────┤
│ERR_REQUEST │ int ERR_REQUEST │
├───────────────────────────┼────────────────────────────┤
│ERR_OP │ int ERR_OP │
├───────────────────────────┼────────────────────────────┤
│ERR_BUFFER │ int ERR_BUFFER │
├───────────────────────────┼────────────────────────────┤
│ERR_COUNT │ int ERR_COUNT │
├───────────────────────────┼────────────────────────────┤
│ERR_TAG │ int ERR_TAG │
├───────────────────────────┼────────────────────────────┤
│ERR_RANK │ int ERR_RANK │
├───────────────────────────┼────────────────────────────┤
│ERR_ROOT │ int ERR_ROOT │
├───────────────────────────┼────────────────────────────┤
│ERR_TRUNCATE │ int ERR_TRUNCATE │
├───────────────────────────┼────────────────────────────┤
│ERR_IN_STATUS │ int ERR_IN_STATUS │
├───────────────────────────┼────────────────────────────┤
│ERR_PENDING │ int ERR_PENDING │
├───────────────────────────┼────────────────────────────┤
│ERR_TOPOLOGY │ int ERR_TOPOLOGY │
├───────────────────────────┼────────────────────────────┤
│ERR_DIMS │ int ERR_DIMS │
├───────────────────────────┼────────────────────────────┤
│ERR_ARG │ int ERR_ARG │
├───────────────────────────┼────────────────────────────┤
│ERR_OTHER │ int ERR_OTHER │
├───────────────────────────┼────────────────────────────┤
│ERR_UNKNOWN │ int ERR_UNKNOWN │
├───────────────────────────┼────────────────────────────┤
│ERR_INTERN │ int ERR_INTERN │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO │ int ERR_INFO │
├───────────────────────────┼────────────────────────────┤
│ERR_FILE │ int ERR_FILE │
├───────────────────────────┼────────────────────────────┤
│ERR_WIN │ int ERR_WIN │
├───────────────────────────┼────────────────────────────┤
│ERR_KEYVAL │ int ERR_KEYVAL │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO_KEY │ int ERR_INFO_KEY │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO_VALUE │ int ERR_INFO_VALUE │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO_NOKEY │ int ERR_INFO_NOKEY │
├───────────────────────────┼────────────────────────────┤
│ERR_ACCESS │ int ERR_ACCESS │
├───────────────────────────┼────────────────────────────┤
│ERR_AMODE │ int ERR_AMODE │
└───────────────────────────┴────────────────────────────┘
│ERR_BAD_FILE │ int ERR_BAD_FILE │
├───────────────────────────┼────────────────────────────┤
│ERR_FILE_EXISTS │ int ERR_FILE_EXISTS │
├───────────────────────────┼────────────────────────────┤
│ERR_FILE_IN_USE │ int ERR_FILE_IN_USE │
├───────────────────────────┼────────────────────────────┤
│ERR_NO_SPACE │ int ERR_NO_SPACE │
├───────────────────────────┼────────────────────────────┤
│ERR_NO_SUCH_FILE │ int ERR_NO_SUCH_FILE │
├───────────────────────────┼────────────────────────────┤
│ERR_IO │ int ERR_IO │
├───────────────────────────┼────────────────────────────┤
│ERR_READ_ONLY │ int ERR_READ_ONLY │
├───────────────────────────┼────────────────────────────┤
│ERR_CONVERSION │ int ERR_CONVERSION │
├───────────────────────────┼────────────────────────────┤
│ERR_DUP_DATAREP │ int ERR_DUP_DATAREP │
├───────────────────────────┼────────────────────────────┤
│ERR_UNSUPPORTED_DATAREP │ int ERR_UNSUP- │
│ │ PORTED_DATAREP │
├───────────────────────────┼────────────────────────────┤
│ERR_UNSUPPORTED_OPERATION │ int ERR_UNSUPPORTED_OPERA- │
│ │ TION │
├───────────────────────────┼────────────────────────────┤
│ERR_NAME │ int ERR_NAME │
├───────────────────────────┼────────────────────────────┤
│ERR_NO_MEM │ int ERR_NO_MEM │
├───────────────────────────┼────────────────────────────┤
│ERR_NOT_SAME │ int ERR_NOT_SAME │
├───────────────────────────┼────────────────────────────┤
│ERR_PORT │ int ERR_PORT │
├───────────────────────────┼────────────────────────────┤
│ERR_QUOTA │ int ERR_QUOTA │
├───────────────────────────┼────────────────────────────┤
│ERR_SERVICE │ int ERR_SERVICE │
├───────────────────────────┼────────────────────────────┤
│ERR_SPAWN │ int ERR_SPAWN │
├───────────────────────────┼────────────────────────────┤
│ERR_BASE │ int ERR_BASE │
├───────────────────────────┼────────────────────────────┤
│ERR_SIZE │ int ERR_SIZE │
├───────────────────────────┼────────────────────────────┤
│ERR_DISP │ int ERR_DISP │
├───────────────────────────┼────────────────────────────┤
│ERR_ASSERT │ int ERR_ASSERT │
├───────────────────────────┼────────────────────────────┤
│ERR_LOCKTYPE │ int ERR_LOCKTYPE │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_CONFLICT │ int ERR_RMA_CONFLICT │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_SYNC │ int ERR_RMA_SYNC │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_RANGE │ int ERR_RMA_RANGE │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_ATTACH │ int ERR_RMA_ATTACH │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_SHARED │ int ERR_RMA_SHARED │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_FLAVOR │ int ERR_RMA_FLAVOR │
├───────────────────────────┼────────────────────────────┤
│ORDER_C │ int ORDER_C │
├───────────────────────────┼────────────────────────────┤
│ORDER_F │ int ORDER_F │
├───────────────────────────┼────────────────────────────┤
│ORDER_FORTRAN │ int ORDER_FORTRAN │
├───────────────────────────┼────────────────────────────┤
│TYPECLASS_INTEGER │ int TYPECLASS_INTEGER │
├───────────────────────────┼────────────────────────────┤
│TYPECLASS_REAL │ int TYPECLASS_REAL │
└───────────────────────────┴────────────────────────────┘
│TYPECLASS_COMPLEX │ int TYPECLASS_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_NONE │ int DISTRIBUTE_NONE │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_BLOCK │ int DISTRIBUTE_BLOCK │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_CYCLIC │ int DISTRIBUTE_CYCLIC │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_DFLT_DARG │ int DISTRIBUTE_DFLT_DARG │
├───────────────────────────┼────────────────────────────┤
│COMBINER_NAMED │ int COMBINER_NAMED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_DUP │ int COMBINER_DUP │
├───────────────────────────┼────────────────────────────┤
│COMBINER_CONTIGUOUS │ int COMBINER_CONTIGUOUS │
├───────────────────────────┼────────────────────────────┤
│COMBINER_VECTOR │ int COMBINER_VECTOR │
├───────────────────────────┼────────────────────────────┤
│COMBINER_HVECTOR │ int COMBINER_HVECTOR │
├───────────────────────────┼────────────────────────────┤
│COMBINER_INDEXED │ int COMBINER_INDEXED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_HINDEXED │ int COMBINER_HINDEXED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_INDEXED_BLOCK │ int COMBINER_INDEXED_BLOCK │
├───────────────────────────┼────────────────────────────┤
│COMBINER_HINDEXED_BLOCK │ int COMBINER_HIN- │
│ │ DEXED_BLOCK │
├───────────────────────────┼────────────────────────────┤
│COMBINER_STRUCT │ int COMBINER_STRUCT │
├───────────────────────────┼────────────────────────────┤
│COMBINER_SUBARRAY │ int COMBINER_SUBARRAY │
├───────────────────────────┼────────────────────────────┤
│COMBINER_DARRAY │ int COMBINER_DARRAY │
├───────────────────────────┼────────────────────────────┤
│COMBINER_RESIZED │ int COMBINER_RESIZED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_F90_REAL │ int COMBINER_F90_REAL │
├───────────────────────────┼────────────────────────────┤
│COMBINER_F90_COMPLEX │ int COMBINER_F90_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│COMBINER_F90_INTEGER │ int COMBINER_F90_INTEGER │
├───────────────────────────┼────────────────────────────┤
│IDENT │ int IDENT │
├───────────────────────────┼────────────────────────────┤
│CONGRUENT │ int CONGRUENT │
├───────────────────────────┼────────────────────────────┤
│SIMILAR │ int SIMILAR │
├───────────────────────────┼────────────────────────────┤
│UNEQUAL │ int UNEQUAL │
├───────────────────────────┼────────────────────────────┤
│CART │ int CART │
├───────────────────────────┼────────────────────────────┤
│GRAPH │ int GRAPH │
├───────────────────────────┼────────────────────────────┤
│DIST_GRAPH │ int DIST_GRAPH │
├───────────────────────────┼────────────────────────────┤
│UNWEIGHTED │ int UNWEIGHTED │
├───────────────────────────┼────────────────────────────┤
│WEIGHTS_EMPTY │ int WEIGHTS_EMPTY │
├───────────────────────────┼────────────────────────────┤
│COMM_TYPE_SHARED │ int COMM_TYPE_SHARED │
├───────────────────────────┼────────────────────────────┤
│BSEND_OVERHEAD │ int BSEND_OVERHEAD │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR_CREATE │ int WIN_FLAVOR_CREATE │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR_ALLOCATE │ int WIN_FLAVOR_ALLOCATE │
└───────────────────────────┴────────────────────────────┘
│WIN_FLAVOR_DYNAMIC │ int WIN_FLAVOR_DYNAMIC │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR_SHARED │ int WIN_FLAVOR_SHARED │
├───────────────────────────┼────────────────────────────┤
│WIN_SEPARATE │ int WIN_SEPARATE │
├───────────────────────────┼────────────────────────────┤
│WIN_UNIFIED │ int WIN_UNIFIED │
├───────────────────────────┼────────────────────────────┤
│MODE_NOCHECK │ int MODE_NOCHECK │
├───────────────────────────┼────────────────────────────┤
│MODE_NOSTORE │ int MODE_NOSTORE │
├───────────────────────────┼────────────────────────────┤
│MODE_NOPUT │ int MODE_NOPUT │
├───────────────────────────┼────────────────────────────┤
│MODE_NOPRECEDE │ int MODE_NOPRECEDE │
├───────────────────────────┼────────────────────────────┤
│MODE_NOSUCCEED │ int MODE_NOSUCCEED │
├───────────────────────────┼────────────────────────────┤
│LOCK_EXCLUSIVE │ int LOCK_EXCLUSIVE │
├───────────────────────────┼────────────────────────────┤
│LOCK_SHARED │ int LOCK_SHARED │
├───────────────────────────┼────────────────────────────┤
│MODE_RDONLY │ int MODE_RDONLY │
├───────────────────────────┼────────────────────────────┤
│MODE_WRONLY │ int MODE_WRONLY │
├───────────────────────────┼────────────────────────────┤
│MODE_RDWR │ int MODE_RDWR │
├───────────────────────────┼────────────────────────────┤
│MODE_CREATE │ int MODE_CREATE │
├───────────────────────────┼────────────────────────────┤
│MODE_EXCL │ int MODE_EXCL │
├───────────────────────────┼────────────────────────────┤
│MODE_DELETE_ON_CLOSE │ int MODE_DELETE_ON_CLOSE │
├───────────────────────────┼────────────────────────────┤
│MODE_UNIQUE_OPEN │ int MODE_UNIQUE_OPEN │
├───────────────────────────┼────────────────────────────┤
│MODE_SEQUENTIAL │ int MODE_SEQUENTIAL │
├───────────────────────────┼────────────────────────────┤
│MODE_APPEND │ int MODE_APPEND │
├───────────────────────────┼────────────────────────────┤
│SEEK_SET │ int SEEK_SET │
├───────────────────────────┼────────────────────────────┤
│SEEK_CUR │ int SEEK_CUR │
├───────────────────────────┼────────────────────────────┤
│SEEK_END │ int SEEK_END │
├───────────────────────────┼────────────────────────────┤
│DISPLACEMENT_CURRENT │ int DISPLACEMENT_CURRENT │
├───────────────────────────┼────────────────────────────┤
│DISP_CUR │ int DISP_CUR │
├───────────────────────────┼────────────────────────────┤
│THREAD_SINGLE │ int THREAD_SINGLE │
├───────────────────────────┼────────────────────────────┤
│THREAD_FUNNELED │ int THREAD_FUNNELED │
├───────────────────────────┼────────────────────────────┤
│THREAD_SERIALIZED │ int THREAD_SERIALIZED │
├───────────────────────────┼────────────────────────────┤
│THREAD_MULTIPLE │ int THREAD_MULTIPLE │
├───────────────────────────┼────────────────────────────┤
│VERSION │ int VERSION │
├───────────────────────────┼────────────────────────────┤
│SUBVERSION │ int SUBVERSION │
├───────────────────────────┼────────────────────────────┤
│MAX_PROCESSOR_NAME │ int MAX_PROCESSOR_NAME │
├───────────────────────────┼────────────────────────────┤
│MAX_ERROR_STRING │ int MAX_ERROR_STRING │
├───────────────────────────┼────────────────────────────┤
│MAX_PORT_NAME │ int MAX_PORT_NAME │
├───────────────────────────┼────────────────────────────┤
│MAX_INFO_KEY │ int MAX_INFO_KEY │
└───────────────────────────┴────────────────────────────┘
│MAX_INFO_VAL │ int MAX_INFO_VAL │
├───────────────────────────┼────────────────────────────┤
│MAX_OBJECT_NAME │ int MAX_OBJECT_NAME │
├───────────────────────────┼────────────────────────────┤
│MAX_DATAREP_STRING │ int MAX_DATAREP_STRING │
├───────────────────────────┼────────────────────────────┤
│MAX_LIBRARY_VERSION_STRING │ int MAX_LIBRARY_VER- │
│ │ SION_STRING │
├───────────────────────────┼────────────────────────────┤
│DATATYPE_NULL │ Datatype DATATYPE_NULL │
├───────────────────────────┼────────────────────────────┤
│UB │ Datatype UB │
├───────────────────────────┼────────────────────────────┤
│LB │ Datatype LB │
├───────────────────────────┼────────────────────────────┤
│PACKED │ Datatype PACKED │
├───────────────────────────┼────────────────────────────┤
│BYTE │ Datatype BYTE │
├───────────────────────────┼────────────────────────────┤
│AINT │ Datatype AINT │
├───────────────────────────┼────────────────────────────┤
│OFFSET │ Datatype OFFSET │
├───────────────────────────┼────────────────────────────┤
│COUNT │ Datatype COUNT │
├───────────────────────────┼────────────────────────────┤
│CHAR │ Datatype CHAR │
├───────────────────────────┼────────────────────────────┤
│WCHAR │ Datatype WCHAR │
├───────────────────────────┼────────────────────────────┤
│SIGNED_CHAR │ Datatype SIGNED_CHAR │
├───────────────────────────┼────────────────────────────┤
│SHORT │ Datatype SHORT │
├───────────────────────────┼────────────────────────────┤
│INT │ Datatype INT │
├───────────────────────────┼────────────────────────────┤
│LONG │ Datatype LONG │
├───────────────────────────┼────────────────────────────┤
│LONG_LONG │ Datatype LONG_LONG │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_CHAR │ Datatype UNSIGNED_CHAR │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_SHORT │ Datatype UNSIGNED_SHORT │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED │ Datatype UNSIGNED │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_LONG │ Datatype UNSIGNED_LONG │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_LONG_LONG │ Datatype UN- │
│ │ SIGNED_LONG_LONG │
├───────────────────────────┼────────────────────────────┤
│FLOAT │ Datatype FLOAT │
├───────────────────────────┼────────────────────────────┤
│DOUBLE │ Datatype DOUBLE │
├───────────────────────────┼────────────────────────────┤
│LONG_DOUBLE │ Datatype LONG_DOUBLE │
├───────────────────────────┼────────────────────────────┤
│C_BOOL │ Datatype C_BOOL │
├───────────────────────────┼────────────────────────────┤
│INT8_T │ Datatype INT8_T │
├───────────────────────────┼────────────────────────────┤
│INT16_T │ Datatype INT16_T │
├───────────────────────────┼────────────────────────────┤
│INT32_T │ Datatype INT32_T │
├───────────────────────────┼────────────────────────────┤
│INT64_T │ Datatype INT64_T │
├───────────────────────────┼────────────────────────────┤
│UINT8_T │ Datatype UINT8_T │
├───────────────────────────┼────────────────────────────┤
│UINT16_T │ Datatype UINT16_T │
└───────────────────────────┴────────────────────────────┘
│UINT32_T │ Datatype UINT32_T │
├───────────────────────────┼────────────────────────────┤
│UINT64_T │ Datatype UINT64_T │
├───────────────────────────┼────────────────────────────┤
│C_COMPLEX │ Datatype C_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│C_FLOAT_COMPLEX │ Datatype C_FLOAT_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│C_DOUBLE_COMPLEX │ Datatype C_DOUBLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│C_LONG_DOUBLE_COMPLEX │ Datatype C_LONG_DOU- │
│ │ BLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│CXX_BOOL │ Datatype CXX_BOOL │
├───────────────────────────┼────────────────────────────┤
│CXX_FLOAT_COMPLEX │ Datatype CXX_FLOAT_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│CXX_DOUBLE_COMPLEX │ Datatype CXX_DOUBLE_COM- │
│ │ PLEX │
├───────────────────────────┼────────────────────────────┤
│CXX_LONG_DOUBLE_COMPLEX │ Datatype CXX_LONG_DOU- │
│ │ BLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│SHORT_INT │ Datatype SHORT_INT │
├───────────────────────────┼────────────────────────────┤
│INT_INT │ Datatype INT_INT │
├───────────────────────────┼────────────────────────────┤
│TWOINT │ Datatype TWOINT │
├───────────────────────────┼────────────────────────────┤
│LONG_INT │ Datatype LONG_INT │
├───────────────────────────┼────────────────────────────┤
│FLOAT_INT │ Datatype FLOAT_INT │
├───────────────────────────┼────────────────────────────┤
│DOUBLE_INT │ Datatype DOUBLE_INT │
├───────────────────────────┼────────────────────────────┤
│LONG_DOUBLE_INT │ Datatype LONG_DOUBLE_INT │
├───────────────────────────┼────────────────────────────┤
│CHARACTER │ Datatype CHARACTER │
├───────────────────────────┼────────────────────────────┤
│LOGICAL │ Datatype LOGICAL │
├───────────────────────────┼────────────────────────────┤
│INTEGER │ Datatype INTEGER │
├───────────────────────────┼────────────────────────────┤
│REAL │ Datatype REAL │
├───────────────────────────┼────────────────────────────┤
│DOUBLE_PRECISION │ Datatype DOUBLE_PRECISION │
├───────────────────────────┼────────────────────────────┤
│COMPLEX │ Datatype COMPLEX │
├───────────────────────────┼────────────────────────────┤
│DOUBLE_COMPLEX │ Datatype DOUBLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│LOGICAL1 │ Datatype LOGICAL1 │
├───────────────────────────┼────────────────────────────┤
│LOGICAL2 │ Datatype LOGICAL2 │
├───────────────────────────┼────────────────────────────┤
│LOGICAL4 │ Datatype LOGICAL4 │
├───────────────────────────┼────────────────────────────┤
│LOGICAL8 │ Datatype LOGICAL8 │
├───────────────────────────┼────────────────────────────┤
│INTEGER1 │ Datatype INTEGER1 │
├───────────────────────────┼────────────────────────────┤
│INTEGER2 │ Datatype INTEGER2 │
├───────────────────────────┼────────────────────────────┤
│INTEGER4 │ Datatype INTEGER4 │
├───────────────────────────┼────────────────────────────┤
│INTEGER8 │ Datatype INTEGER8 │
├───────────────────────────┼────────────────────────────┤
│INTEGER16 │ Datatype INTEGER16 │
└───────────────────────────┴────────────────────────────┘
│REAL2 │ Datatype REAL2 │
├───────────────────────────┼────────────────────────────┤
│REAL4 │ Datatype REAL4 │
├───────────────────────────┼────────────────────────────┤
│REAL8 │ Datatype REAL8 │
├───────────────────────────┼────────────────────────────┤
│REAL16 │ Datatype REAL16 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX4 │ Datatype COMPLEX4 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX8 │ Datatype COMPLEX8 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX16 │ Datatype COMPLEX16 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX32 │ Datatype COMPLEX32 │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_INT │ Datatype UNSIGNED_INT │
├───────────────────────────┼────────────────────────────┤
│SIGNED_SHORT │ Datatype SIGNED_SHORT │
├───────────────────────────┼────────────────────────────┤
│SIGNED_INT │ Datatype SIGNED_INT │
├───────────────────────────┼────────────────────────────┤
│SIGNED_LONG │ Datatype SIGNED_LONG │
├───────────────────────────┼────────────────────────────┤
│SIGNED_LONG_LONG │ Datatype SIGNED_LONG_LONG │
├───────────────────────────┼────────────────────────────┤
│BOOL │ Datatype BOOL │
├───────────────────────────┼────────────────────────────┤
│SINT8_T │ Datatype SINT8_T │
├───────────────────────────┼────────────────────────────┤
│SINT16_T │ Datatype SINT16_T │
├───────────────────────────┼────────────────────────────┤
│SINT32_T │ Datatype SINT32_T │
├───────────────────────────┼────────────────────────────┤
│SINT64_T │ Datatype SINT64_T │
├───────────────────────────┼────────────────────────────┤
│F_BOOL │ Datatype F_BOOL │
├───────────────────────────┼────────────────────────────┤
│F_INT │ Datatype F_INT │
├───────────────────────────┼────────────────────────────┤
│F_FLOAT │ Datatype F_FLOAT │
├───────────────────────────┼────────────────────────────┤
│F_DOUBLE │ Datatype F_DOUBLE │
├───────────────────────────┼────────────────────────────┤
│F_COMPLEX │ Datatype F_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│F_FLOAT_COMPLEX │ Datatype F_FLOAT_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│F_DOUBLE_COMPLEX │ Datatype F_DOUBLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│REQUEST_NULL │ Request REQUEST_NULL │
├───────────────────────────┼────────────────────────────┤
│MESSAGE_NULL │ Message MESSAGE_NULL │
├───────────────────────────┼────────────────────────────┤
│MESSAGE_NO_PROC │ Message MESSAGE_NO_PROC │
├───────────────────────────┼────────────────────────────┤
│OP_NULL │ Op OP_NULL │
├───────────────────────────┼────────────────────────────┤
│MAX │ Op MAX │
├───────────────────────────┼────────────────────────────┤
│MIN │ Op MIN │
├───────────────────────────┼────────────────────────────┤
│SUM │ Op SUM │
├───────────────────────────┼────────────────────────────┤
│PROD │ Op PROD │
├───────────────────────────┼────────────────────────────┤
│LAND │ Op LAND │
├───────────────────────────┼────────────────────────────┤
│BAND │ Op BAND │
└───────────────────────────┴────────────────────────────┘
│LOR │ Op LOR │
├───────────────────────────┼────────────────────────────┤
│BOR │ Op BOR │
├───────────────────────────┼────────────────────────────┤
│LXOR │ Op LXOR │
├───────────────────────────┼────────────────────────────┤
│BXOR │ Op BXOR │
├───────────────────────────┼────────────────────────────┤
│MAXLOC │ Op MAXLOC │
├───────────────────────────┼────────────────────────────┤
│MINLOC │ Op MINLOC │
├───────────────────────────┼────────────────────────────┤
│REPLACE │ Op REPLACE │
├───────────────────────────┼────────────────────────────┤
│NO_OP │ Op NO_OP │
├───────────────────────────┼────────────────────────────┤
│GROUP_NULL │ Group GROUP_NULL │
├───────────────────────────┼────────────────────────────┤
│GROUP_EMPTY │ Group GROUP_EMPTY │
├───────────────────────────┼────────────────────────────┤
│INFO_NULL │ Info INFO_NULL │
├───────────────────────────┼────────────────────────────┤
│INFO_ENV │ Info INFO_ENV │
├───────────────────────────┼────────────────────────────┤
│ERRHANDLER_NULL │ Errhandler ERRHANDLER_NULL │
├───────────────────────────┼────────────────────────────┤
│ERRORS_RETURN │ Errhandler ERRORS_RETURN │
├───────────────────────────┼────────────────────────────┤
│ERRORS_ARE_FATAL │ Errhandler ERRORS_ARE_FA- │
│ │ TAL │
├───────────────────────────┼────────────────────────────┤
│COMM_NULL │ Comm COMM_NULL │
├───────────────────────────┼────────────────────────────┤
│COMM_SELF │ Intracomm COMM_SELF │
├───────────────────────────┼────────────────────────────┤
│COMM_WORLD │ Intracomm COMM_WORLD │
├───────────────────────────┼────────────────────────────┤
│WIN_NULL │ Win WIN_NULL │
├───────────────────────────┼────────────────────────────┤
│FILE_NULL │ File FILE_NULL │
├───────────────────────────┼────────────────────────────┤
│pickle │ Pickle pickle │
└───────────────────────────┴────────────────────────────┘
MPI4PY.FUTURES
New in version 3.0.0.
This package provides a high-level interface for asynchronously execut-
ing callables on a pool of worker processes using MPI for inter-process
communication.
concurrent.futures
The mpi4py.futures package is based on concurrent.futures from the
Python standard library. More precisely, mpi4py.futures provides the
MPIPoolExecutor class as a concrete implementation of the abstract
class Executor. The submit() interface schedules a callable to be exe-
cuted asynchronously and returns a Future object representing the exe-
cution of the callable. Future instances can be queried for the call
result or exception. Sets of Future instances can be passed to the
wait() and as_completed() functions.
NOTE:
The concurrent.futures package was introduced in Python 3.2. A
backport targeting Python 2.7 is available on PyPI. The
mpi4py.futures package uses concurrent.futures if available, either
from the Python 3 standard library or the Python 2.7 backport if in-
stalled. Otherwise, mpi4py.futures uses a bundled copy of core func-
tionality backported from Python 3.5 to work with Python 2.7.
SEE ALSO:
Module concurrent.futures
Documentation of the concurrent.futures standard module.
MPIPoolExecutor
The MPIPoolExecutor class uses a pool of MPI processes to execute calls
asynchronously. By performing computations in separate processes, it
allows to side-step the global interpreter lock but also means that
only picklable objects can be executed and returned. The __main__ mod-
ule must be importable by worker processes, thus MPIPoolExecutor in-
stances may not work in the interactive interpreter.
MPIPoolExecutor takes advantage of the dynamic process management fea-
tures introduced in the MPI-2 standard. In particular, the MPI.Intra-
comm.Spawn method of MPI.COMM_SELF is used in the master (or parent)
process to spawn new worker (or child) processes running a Python in-
terpreter. The master process uses a separate thread (one for each
MPIPoolExecutor instance) to communicate back and forth with the work-
ers. The worker processes serve the execution of tasks in the main
(and only) thread until they are signaled for completion.
NOTE:
The worker processes must import the main script in order to un-
pickle any callable defined in the __main__ module and submitted
from the master process. Furthermore, the callables may need access
to other global variables. At the worker processes, mpi4py.futures
executes the main script code (using the runpy module) under the
__worker__ namespace to define the __main__ module. The __main__ and
__worker__ modules are added to sys.modules (both at the master and
worker processes) to ensure proper pickling and unpickling.
WARNING:
During the initial import phase at the workers, the main script can-
not create and use new MPIPoolExecutor instances. Otherwise, each
worker would attempt to spawn a new pool of workers, leading to in-
finite recursion. mpi4py.futures detects such recursive attempts to
spawn new workers and aborts the MPI execution environment. As the
main script code is run under the __worker__ namespace, the easiest
way to avoid spawn recursion is using the idiom if __name__ ==
'__main__': ... in the main script.
class mpi4py.futures.MPIPoolExecutor(max_workers=None, initial-
izer=None, initargs=(), **kwargs)
An Executor subclass that executes calls asynchronously using a
pool of at most max_workers processes. If max_workers is None
or not given, its value is determined from the
MPI4PY_FUTURES_MAX_WORKERS environment variable if set, or the
MPI universe size if set, otherwise a single worker process is
spawned. If max_workers is lower than or equal to 0, then a
ValueError will be raised.
initializer is an optional callable that is called at the start
of each worker process before executing any tasks; initargs is a
tuple of arguments passed to the initializer. If initializer
raises an exception, all pending tasks and any attempt to submit
new tasks to the pool will raise a BrokenExecutor exception.
Other parameters:
• python_exe: Path to the Python interpreter executable used to
spawn worker processes, otherwise sys.executable is used.
• python_args: list or iterable with additional command line
flags to pass to the Python executable. Command line flags de-
termined from inspection of sys.flags, sys.warnoptions and
sys._xoptions in are passed unconditionally.
• mpi_info: dict or iterable yielding (key, value) pairs. These
(key, value) pairs are passed (through an MPI.Info object) to
the MPI.Intracomm.Spawn call used to spawn worker processes.
This mechanism allows telling the MPI runtime system where and
how to start the processes. Check the documentation of the
backend MPI implementation about the set of keys it interprets
and the corresponding format for values.
• globals: dict or iterable yielding (name, value) pairs to ini-
tialize the main module namespace in worker processes.
• main: If set to False, do not import the __main__ module in
worker processes. Setting main to False prevents worker pro-
cesses from accessing definitions in the parent __main__ name-
space.
• path: list or iterable with paths to append to sys.path in
worker processes to extend the module search path.
• wdir: Path to set the current working directory in worker pro-
cesses using os.chdir(). The initial working directory is set
by the MPI implementation. Quality MPI implementations should
honor a wdir info key passed through mpi_info, although such
feature is not mandatory.
• env: dict or iterable yielding (name, value) pairs with envi-
ronment variables to update os.environ in worker processes.
The initial environment is set by the MPI implementation. MPI
implementations may allow setting the initial environment
through mpi_info, however such feature is not required nor
recommended by the MPI standard.
submit(func, *args, **kwargs)
Schedule the callable, func, to be executed as
func(*args, **kwargs) and returns a Future object repre-
senting the execution of the callable.
executor = MPIPoolExecutor(max_workers=1)
future = executor.submit(pow, 321, 1234)
print(future.result())
map(func, *iterables, timeout=None, chunksize=1, **kwargs)
Equivalent to map(func, *iterables) except func is exe-
cuted asynchronously and several calls to func may be
made concurrently, out-of-order, in separate processes.
The returned iterator raises a TimeoutError if __next__()
is called and the result isn’t available after timeout
seconds from the original call to map(). timeout can be
an int or a float. If timeout is not specified or None,
there is no limit to the wait time. If a call raises an
exception, then that exception will be raised when its
value is retrieved from the iterator. This method chops
iterables into a number of chunks which it submits to the
pool as separate tasks. The (approximate) size of these
chunks can be specified by setting chunksize to a posi-
tive integer. For very long iterables, using a large
value for chunksize can significantly improve performance
compared to the default size of one. By default, the re-
turned iterator yields results in-order, waiting for suc-
cessive tasks to complete . This behavior can be changed
by passing the keyword argument unordered as True, then
the result iterator will yield a result as soon as any of
the tasks complete.
executor = MPIPoolExecutor(max_workers=3)
for result in executor.map(pow, [2]*32, range(32)):
print(result)
starmap(func, iterable, timeout=None, chunksize=1, **kwargs)
Equivalent to itertools.starmap(func, iterable). Used in-
stead of map() when argument parameters are already
grouped in tuples from a single iterable (the data has
been “pre-zipped”). map(func, *iterable) is equivalent to
starmap(func, zip(*iterable)).
executor = MPIPoolExecutor(max_workers=3)
iterable = ((2, n) for n in range(32))
for result in executor.starmap(pow, iterable):
print(result)
shutdown(wait=True, cancel_futures=False)
Signal the executor that it should free any resources
that it is using when the currently pending futures are
done executing. Calls to submit() and map() made after
shutdown() will raise RuntimeError.
If wait is True then this method will not return until
all the pending futures are done executing and the re-
sources associated with the executor have been freed. If
wait is False then this method will return immediately
and the resources associated with the executor will be
freed when all pending futures are done executing. Re-
gardless of the value of wait, the entire Python program
will not exit until all pending futures are done execut-
ing.
If cancel_futures is True, this method will cancel all
pending futures that the executor has not started run-
ning. Any futures that are completed or running won’t be
cancelled, regardless of the value of cancel_futures.
You can avoid having to call this method explicitly if
you use the with statement, which will shutdown the ex-
ecutor instance (waiting as if shutdown() were called
with wait set to True).
import time
with MPIPoolExecutor(max_workers=1) as executor:
future = executor.submit(time.sleep, 2)
assert future.done()
bootup(wait=True)
Signal the executor that it should allocate eagerly any
required resources (in particular, MPI worker processes).
If wait is True, then bootup() will not return until the
executor resources are ready to process submissions. Re-
sources are automatically allocated in the first call to
submit(), thus calling bootup() explicitly is seldom
needed.
MPI4PY_FUTURES_MAX_WORKERS
If the max_workers parameter to MPIPoolExecutor is None or not
given, the MPI4PY_FUTURES_MAX_WORKERS environment variable pro-
vides fallback value for the maximum number of MPI worker pro-
cesses to spawn.
NOTE:
As the master process uses a separate thread to perform MPI communi-
cation with the workers, the backend MPI implementation should pro-
vide support for MPI.THREAD_MULTIPLE. However, some popular MPI im-
plementations do not support yet concurrent MPI calls from multiple
threads. Additionally, users may decide to initialize MPI with a
lower level of thread support. If the level of thread support in the
backend MPI is less than MPI.THREAD_MULTIPLE, mpi4py.futures will
use a global lock to serialize MPI calls. If the level of thread
support is less than MPI.THREAD_SERIALIZED, mpi4py.futures will emit
a RuntimeWarning.
WARNING:
If the level of thread support in the backend MPI is less than
MPI.THREAD_SERIALIZED (i.e, it is either MPI.THREAD_SINGLE or
MPI.THREAD_FUNNELED), in theory mpi4py.futures cannot be used.
Rather than raising an exception, mpi4py.futures emits a warning and
takes a “cross-fingers” attitude to continue execution in the hope
that serializing MPI calls with a global lock will actually work.
MPICommExecutor
Legacy MPI-1 implementations (as well as some vendor MPI-2 implementa-
tions) do not support the dynamic process management features intro-
duced in the MPI-2 standard. Additionally, job schedulers and batch
systems in supercomputing facilities may pose additional complications
to applications using the MPI_Comm_spawn() routine.
With these issues in mind, mpi4py.futures supports an additonal, more
traditional, SPMD-like usage pattern requiring MPI-1 calls only. Python
applications are started the usual way, e.g., using the mpiexec com-
mand. Python code should make a collective call to the MPICommExecutor
context manager to partition the set of MPI processes within a MPI com-
municator in one master processes and many workers processes. The mas-
ter process gets access to an MPIPoolExecutor instance to submit tasks.
Meanwhile, the worker process follow a different execution path and
team-up to execute the tasks submitted from the master.
Besides alleviating the lack of dynamic process managment features in
legacy MPI-1 or partial MPI-2 implementations, the MPICommExecutor con-
text manager may be useful in classic MPI-based Python applications
willing to take advantage of the simple, task-based, master/worker ap-
proach available in the mpi4py.futures package.
class mpi4py.futures.MPICommExecutor(comm=None, root=0)
Context manager for MPIPoolExecutor. This context manager splits
a MPI (intra)communicator comm (defaults to MPI.COMM_WORLD if
not provided or None) in two disjoint sets: a single master
process (with rank root in comm) and the remaining worker pro-
cesses. These sets are then connected through an intercommunica-
tor. The target of the with statement is assigned either an
MPIPoolExecutor instance (at the master) or None (at the work-
ers).
from mpi4py import MPI
from mpi4py.futures import MPICommExecutor
with MPICommExecutor(MPI.COMM_WORLD, root=0) as executor:
if executor is not None:
future = executor.submit(abs, -42)
assert future.result() == 42
answer = set(executor.map(abs, [-42, 42]))
assert answer == {42}
WARNING:
If MPICommExecutor is passed a communicator of size one (e.g.,
MPI.COMM_SELF), then the executor instace assigned to the target of
the with statement will execute all submitted tasks in a single
worker thread, thus ensuring that task execution still progress
asynchronously. However, the GIL will prevent the main and worker
threads from running concurrently in multicore processors. Moreover,
the thread context switching may harm noticeably the performance of
CPU-bound tasks. In case of I/O-bound tasks, the GIL is not usually
an issue, however, as a single worker thread is used, it progress
one task at a time. We advice against using MPICommExecutor with
communicators of size one and suggest refactoring your code to use
instead a ThreadPoolExecutor.
Command line
Recalling the issues related to the lack of support for dynamic process
managment features in MPI implementations, mpi4py.futures supports an
alternative usage pattern where Python code (either from scripts, mod-
ules, or zip files) is run under command line control of the
mpi4py.futures package by passing -m mpi4py.futures to the python exe-
cutable. The mpi4py.futures invocation should be passed a pyfile path
to a script (or a zipfile/directory containing a __main__.py file).
Additionally, mpi4py.futures accepts -m mod to execute a module named
mod, -c cmd to execute a command string cmd, or even - to read commands
from standard input (sys.stdin). Summarizing, mpi4py.futures can be
invoked in the following ways:
• $ mpiexec -n numprocs python -m mpi4py.futures pyfile [arg] ...
• $ mpiexec -n numprocs python -m mpi4py.futures -m mod [arg] ...
• $ mpiexec -n numprocs python -m mpi4py.futures -c cmd [arg] ...
• $ mpiexec -n numprocs python -m mpi4py.futures - [arg] ...
Before starting the main script execution, mpi4py.futures splits
MPI.COMM_WORLD in one master (the process with rank 0 in
MPI.COMM_WORLD) and numprocs - 1 workers and connects them through an
MPI intercommunicator. Afterwards, the master process proceeds with
the execution of the user script code, which eventually creates
MPIPoolExecutor instances to submit tasks. Meanwhile, the worker pro-
cesses follow a different execution path to serve the master. Upon
successful termination of the main script at the master, the entire MPI
execution environment exists gracefully. In case of any unhandled ex-
ception in the main script, the master process calls
MPI.COMM_WORLD.Abort(1) to prevent deadlocks and force termination of
entire MPI execution environment.
WARNING:
Running scripts under command line control of mpi4py.futures is
quite similar to executing a single-process application that spawn
additional workers as required. However, there is a very important
difference users should be aware of. All MPIPoolExecutor instances
created at the master will share the pool of workers. Tasks submit-
ted at the master from many different executors will be scheduled
for execution in random order as soon as a worker is idle. Any ex-
ecutor can easily starve all the workers (e.g., by calling
MPIPoolExecutor.map() with long iterables). If that ever happens,
submissions from other executors will not be serviced until free
workers are available.
SEE ALSO:
python:using-on-cmdline
Documentation on Python command line interface.
Examples
The following julia.py script computes the Julia set and dumps an image
to disk in binary PGM format. The code starts by importing
MPIPoolExecutor from the mpi4py.futures package. Next, some global con-
stants and functions implement the computation of the Julia set. The
computations are protected with the standard if __name__ ==
'__main__':... idiom. The image is computed by whole scanlines sub-
mitting all these tasks at once using the map method. The result itera-
tor yields scanlines in-order as the tasks complete. Finally, each
scanline is dumped to disk.
julia.py
from mpi4py.futures import MPIPoolExecutor
x0, x1, w = -2.0, +2.0, 640*2
y0, y1, h = -1.5, +1.5, 480*2
dx = (x1 - x0) / w
dy = (y1 - y0) / h
c = complex(0, 0.65)
def julia(x, y):
z = complex(x, y)
n = 255
while abs(z) < 3 and n > 1:
z = z**2 + c
n -= 1
return n
def julia_line(k):
line = bytearray(w)
y = y1 - k * dy
for j in range(w):
x = x0 + j * dx
line[j] = julia(x, y)
return line
if __name__ == '__main__':
with MPIPoolExecutor() as executor:
image = executor.map(julia_line, range(h))
with open('julia.pgm', 'wb') as f:
f.write(b'P5 %d %d %d\n' % (w, h, 255))
for line in image:
f.write(line)
The recommended way to execute the script is by using the mpiexec com-
mand specifying one MPI process (master) and (optional but recommended)
the desired MPI universe size, which determines the number of addi-
tional dynamically spawned processes (workers). The MPI universe size
is provided either by a batch system or set by the user via com-
mand-line arguments to mpiexec or environment variables. Below we pro-
vide examples for MPICH and Open MPI implementations [1]. In all of
these examples, the mpiexec command launches a single master process
running the Python interpreter and executing the main script. When re-
quired, mpi4py.futures spawns the pool of 16 worker processes. The mas-
ter submits tasks to the workers and waits for the results. The workers
receive incoming tasks, execute them, and send back the results to the
master.
When using MPICH implementation or its derivatives based on the Hydra
process manager, users can set the MPI universe size via the -usize ar-
gument to mpiexec:
$ mpiexec -n 1 -usize 17 python julia.py
or, alternatively, by setting the MPIEXEC_UNIVERSE_SIZE environment
variable:
$ MPIEXEC_UNIVERSE_SIZE=17 mpiexec -n 1 python julia.py
In the Open MPI implementation, the MPI universe size can be set via
the -host argument to mpiexec:
$ mpiexec -n 1 -host <hostname>:17 python julia.py
Another way to specify the number of workers is to use the
mpi4py.futures-specific environment variable
MPI4PY_FUTURES_MAX_WORKERS:
$ MPI4PY_FUTURES_MAX_WORKERS=16 mpiexec -n 1 python julia.py
Note that in this case, the MPI universe size is ignored.
Alternatively, users may decide to execute the script in a more tradi-
tional way, that is, all the MPI processes are started at once. The
user script is run under command-line control of mpi4py.futures passing
the -m flag to the python executable:
$ mpiexec -n 17 python -m mpi4py.futures julia.py
As explained previously, the 17 processes are partitioned in one master
and 16 workers. The master process executes the main script while the
workers execute the tasks submitted by the master.
[1] When using an MPI implementation other than MPICH or Open MPI,
please check the documentation of the implementation and/or batch
system for the ways to specify the desired MPI universe size.
GIL See global interpreter lock.
MPI4PY.UTIL
New in version 3.1.0.
The mpi4py.util package collects miscellaneous utilities within the in-
tersection of Python and MPI.
mpi4py.util.pkl5
New in version 3.1.0.
pickle protocol 5 (see PEP 574) introduced support for out-of-band buf-
fers, allowing for more efficient handling of certain object types with
large memory footprints.
MPI for Python uses the traditional in-band handling of buffers. This
approach is appropriate for communicating non-buffer Python objects, or
buffer-like objects with small memory footprints. For point-to-point
communication, in-band buffer handling allows for the communication of
a pickled stream with a single MPI message, at the expense of addi-
tional CPU and memory overhead in the pickling and unpickling steps.
The mpi4py.util.pkl5 module provides communicator wrapper classes reim-
plementing pickle-based point-to-point communication methods using
pickle protocol 5. Handling out-of-band buffers necessarily involve
multiple MPI messages, thus increasing latency and hurting performance
in case of small size data. However, in case of large size data, the
zero-copy savings of out-of-band buffer handling more than offset the
extra latency costs. Additionally, these wrapper methods overcome the
infamous 2 GiB message count limit (MPI-1 to MPI-3).
NOTE:
Support for pickle protocol 5 is available in the pickle module
within the Python standard library since Python 3.8. Previous Python
3 releases can use the pickle5 backport, which is available on PyPI
and can be installed with:
python -m pip install pickle5
class mpi4py.util.pkl5.Request(request=None)
Request.
Custom request class for nonblocking communications.
NOTE:
Request is not a subclass of mpi4py.MPI.Request
Parameters
request (Iterable[MPI.Request]) –
Return type
Request
Free() Free a communication request.
Return type
None
cancel()
Cancel a communication request.
Return type
None
get_status(status=None)
Non-destructive test for the completion of a request.
Parameters
status (Optional[Status]) –
Return type
bool
test(status=None)
Test for the completion of a request.
Parameters
status (Optional[Status]) –
Return type
Tuple[bool, Optional[Any]]
wait(status=None)
Wait for a request to complete.
Parameters
status (Optional[Status]) –
Return type
Any
classmethod testall(requests, statuses=None)
Test for the completion of all requests.
Classmethod
classmethod waitall(requests, statuses=None)
Wait for all requests to complete.
Classmethod
class mpi4py.util.pkl5.Message(message=None)
Message.
Custom message class for matching probes.
NOTE:
Message is not a subclass of mpi4py.MPI.Message
Parameters
message (Iterable[MPI.Message]) –
Return type
Message
recv(status=None)
Blocking receive of matched message.
Parameters
status (Optional[Status]) –
Return type
Any
irecv()
Nonblocking receive of matched message.
Return type
Request
classmethod probe(comm, source=ANY_SOURCE, tag=ANY_TAG, sta-
tus=None)
Blocking test for a matched message.
Classmethod
classmethod iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, sta-
tus=None)
Nonblocking test for a matched message.
Classmethod
class mpi4py.util.pkl5.Comm
Communicator.
Base communicator wrapper class.
send(obj, dest, tag=0)
Blocking send in standard mode.
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
None
bsend(obj, dest, tag=0)
Blocking send in buffered mode.
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
None
ssend(obj, dest, tag=0)
Blocking send in synchronous mode.
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
None
isend(obj, dest, tag=0)
Nonblocking send in standard mode.
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
Request
ibsend(obj, dest, tag=0)
Nonblocking send in buffered mode.
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
Request
issend(obj, dest, tag=0)
Nonblocking send in synchronous mode.
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
Request
recv(buf=None, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking receive.
Parameters
• buf (Optional[Buffer]) –
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Any
irecv(buf=None, source=ANY_SOURCE, tag=ANY_TAG)
Nonblocking receive.
WARNING:
This method cannot be supported reliably and raises
RuntimeError.
Parameters
• buf (Optional[Buffer]) –
• source (int) –
• tag (int) –
Return type
Request
sendrecv(sendobj, dest, sendtag=0, recvbuf=None,
source=ANY_SOURCE, recvtag=ANY_TAG, status=None)
Send and receive.
Parameters
• sendobj (Any) –
• dest (int) –
• sendtag (int) –
• recvbuf (Optional[Buffer]) –
• source (int) –
• recvtag (int) –
• status (Optional[Status]) –
Return type
Any
mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message.
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Message
improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message.
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Optional[Message]
bcast(obj, root=0)
Broadcast.
Parameters
• obj (Any) –
• root (int) –
Return type
Any
class mpi4py.util.pkl5.Intracomm
Intracommunicator.
Intracommunicator wrapper class.
class mpi4py.util.pkl5.Intercomm
Intercommunicator.
Intercommunicator wrapper class.
Examples
test-pkl5-1.py
import numpy as np
from mpi4py import MPI
from mpi4py.util import pkl5
comm = pkl5.Intracomm(MPI.COMM_WORLD) # comm wrapper
size = comm.Get_size()
rank = comm.Get_rank()
dst = (rank + 1) % size
src = (rank - 1) % size
sobj = np.full(1024**3, rank, dtype='i4') # > 4 GiB
sreq = comm.isend(sobj, dst, tag=42)
robj = comm.recv (None, src, tag=42)
sreq.Free()
assert np.min(robj) == src
assert np.max(robj) == src
test-pkl5-2.py
import numpy as np
from mpi4py import MPI
from mpi4py.util import pkl5
comm = pkl5.Intracomm(MPI.COMM_WORLD) # comm wrapper
size = comm.Get_size()
rank = comm.Get_rank()
dst = (rank + 1) % size
src = (rank - 1) % size
sobj = np.full(1024**3, rank, dtype='i4') # > 4 GiB
sreq = comm.isend(sobj, dst, tag=42)
status = MPI.Status()
rmsg = comm.mprobe(status=status)
assert status.Get_source() == src
assert status.Get_tag() == 42
rreq = rmsg.irecv()
robj = rreq.wait()
sreq.Free()
assert np.max(robj) == src
assert np.min(robj) == src
mpi4py.util.dtlib
New in version 3.1.0.
The mpi4py.util.dtlib module provides converter routines between NumPy
and MPI datatypes.
mpi4py.util.dtlib.from_numpy_dtype(dtype)
Convert NumPy datatype to MPI datatype.
Parameters
dtype (numpy.typing.DTypeLike) – NumPy dtype-like object.
Return type
Datatype
mpi4py.util.dtlib.to_numpy_dtype(datatype)
Convert MPI datatype to NumPy datatype.
Parameters
datatype (Datatype) – MPI datatype.
Return type
numpy.dtype
MPI4PY.RUN
New in version 3.0.0.
At import time, mpi4py initializes the MPI execution environment call-
ing MPI_Init_thread() and installs an exit hook to automatically call
MPI_Finalize() just before the Python process terminates. Additionally,
mpi4py overrides the default ERRORS_ARE_FATAL error handler in favor of
ERRORS_RETURN, which allows translating MPI errors in Python excep-
tions. These departures from standard MPI behavior may be controver-
sial, but are quite convenient within the highly dynamic Python pro-
gramming environment. Third-party code using mpi4py can just from
mpi4py import MPI and perform MPI calls without the tedious initializa-
tion/finalization handling. MPI errors, once translated automatically
to Python exceptions, can be dealt with the common try…except…finally
clauses; unhandled MPI exceptions will print a traceback which helps in
locating problems in source code.
Unfortunately, the interplay of automatic MPI finalization and unhan-
dled exceptions may lead to deadlocks. In unattended runs, these dead-
locks will drain the battery of your laptop, or burn precious alloca-
tion hours in your supercomputing facility.
Consider the following snippet of Python code. Assume this code is
stored in a standard Python script file and run with mpiexec in two or
more processes.
from mpi4py import MPI
assert MPI.COMM_WORLD.Get_size() > 1
rank = MPI.COMM_WORLD.Get_rank()
if rank == 0:
1/0
MPI.COMM_WORLD.send(None, dest=1, tag=42)
elif rank == 1:
MPI.COMM_WORLD.recv(source=0, tag=42)
Process 0 raises ZeroDivisionError exception before performing a send
call to process 1. As the exception is not handled, the Python inter-
preter running in process 0 will proceed to exit with non-zero status.
However, as mpi4py installed a finalizer hook to call MPI_Finalize()
before exit, process 0 will block waiting for other processes to also
enter the MPI_Finalize() call. Meanwhile, process 1 will block waiting
for a message to arrive from process 0, thus never reaching to MPI_Fi-
nalize(). The whole MPI execution environment is irremediably in a
deadlock state.
To alleviate this issue, mpi4py offers a simple, alternative command
line execution mechanism based on using the -m flag and implemented
with the runpy module. To use this features, Python code should be run
passing -m mpi4py in the command line invoking the Python interpreter.
In case of unhandled exceptions, the finalizer hook will call
MPI_Abort() on the MPI_COMM_WORLD communicator, thus effectively abort-
ing the MPI execution environment.
WARNING:
When a process is forced to abort, resources (e.g. open files) are
not cleaned-up and any registered finalizers (either with the atexit
module, the Python C/API function Py_AtExit(), or even the C stan-
dard library function atexit()) will not be executed. Thus, aborting
execution is an extremely impolite way of ensuring process termina-
tion. However, MPI provides no other mechanism to recover from a
deadlock state.
Interface options
The use of -m mpi4py to execute Python code on the command line resem-
bles that of the Python interpreter.
• mpiexec -n numprocs python -m mpi4py pyfile [arg] ...
• mpiexec -n numprocs python -m mpi4py -m mod [arg] ...
• mpiexec -n numprocs python -m mpi4py -c cmd [arg] ...
• mpiexec -n numprocs python -m mpi4py - [arg] ...
<pyfile>
Execute the Python code contained in pyfile, which must be a
filesystem path referring to either a Python file, a directory
containing a __main__.py file, or a zipfile containing a
__main__.py file.
-m <mod>
Search sys.path for the named module mod and execute its con-
tents.
-c <cmd>
Execute the Python code in the cmd string command.
- Read commands from standard input (sys.stdin).
SEE ALSO:
python:using-on-cmdline
Documentation on Python command line interface.
REFERENCE
┌───────────┬────────────────────────────┐
│mpi4py.MPI │ Message Passing Interface. │
└───────────┴────────────────────────────┘
mpi4py.MPI
Message Passing Interface.
Classes
┌───────────────────────────┬────────────────────────────┐
│Cartcomm([comm]) │ Cartesian topology intra- │
│ │ communicator │
├───────────────────────────┼────────────────────────────┤
│Comm([comm]) │ Communicator │
├───────────────────────────┼────────────────────────────┤
│Datatype([datatype]) │ Datatype object │
├───────────────────────────┼────────────────────────────┤
│Distgraphcomm([comm]) │ Distributed graph topology │
│ │ intracommunicator │
├───────────────────────────┼────────────────────────────┤
│Errhandler([errhandler]) │ Error handler │
├───────────────────────────┼────────────────────────────┤
│File([file]) │ File handle │
├───────────────────────────┼────────────────────────────┤
│Graphcomm([comm]) │ General graph topology in- │
│ │ tracommunicator │
├───────────────────────────┼────────────────────────────┤
│Grequest([request]) │ Generalized request handle │
├───────────────────────────┼────────────────────────────┤
│Group([group]) │ Group of processes │
├───────────────────────────┼────────────────────────────┤
│Info([info]) │ Info object │
├───────────────────────────┼────────────────────────────┤
│Intercomm([comm]) │ Intercommunicator │
├───────────────────────────┼────────────────────────────┤
│Intracomm([comm]) │ Intracommunicator │
├───────────────────────────┼────────────────────────────┤
│Message([message]) │ Matched message handle │
└───────────────────────────┴────────────────────────────┘
│Op([op]) │ Operation object │
├───────────────────────────┼────────────────────────────┤
│Pickle([dumps, loads, pro- │ Pickle/unpickle Python ob- │
│tocol]) │ jects │
├───────────────────────────┼────────────────────────────┤
│Prequest([request]) │ Persistent request handle │
├───────────────────────────┼────────────────────────────┤
│Request([request]) │ Request handle │
├───────────────────────────┼────────────────────────────┤
│Status([status]) │ Status object │
├───────────────────────────┼────────────────────────────┤
│Topocomm([comm]) │ Topology intracommunicator │
├───────────────────────────┼────────────────────────────┤
│Win([win]) │ Window handle │
├───────────────────────────┼────────────────────────────┤
│memory(buf) │ Memory buffer │
└───────────────────────────┴────────────────────────────┘
mpi4py.MPI.Cartcomm
class mpi4py.MPI.Cartcomm(comm=None)
Bases: mpi4py.MPI.Topocomm
Cartesian topology intracommunicator
Parameters
comm (Optional[Cartcomm]) –
Return type
Cartcomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Cartcomm]) –
Return type
Cartcomm
Methods Summary
┌───────────────────────┬────────────────────────────┐
│Get_cart_rank(coords) │ Translate logical coordi- │
│ │ nates to ranks │
├───────────────────────┼────────────────────────────┤
│Get_coords(rank) │ Translate ranks to logical │
│ │ coordinates │
├───────────────────────┼────────────────────────────┤
│Get_dim() │ Return number of dimen- │
│ │ sions │
├───────────────────────┼────────────────────────────┤
│Get_topo() │ Return information on the │
│ │ cartesian topology │
├───────────────────────┼────────────────────────────┤
│Shift(direction, disp) │ Return a tuple (source, │
│ │ dest) of process ranks for │
│ │ data shifting with │
│ │ Comm.Sendrecv() │
├───────────────────────┼────────────────────────────┤
│Sub(remain_dims) │ Return cartesian communi- │
│ │ cators that form lower-di- │
│ │ mensional subgrids │
└───────────────────────┴────────────────────────────┘
Attributes Summary
┌────────┬──────────────────────┐
│coords │ coordinates │
├────────┼──────────────────────┤
│dim │ number of dimensions │
├────────┼──────────────────────┤
│dims │ dimensions │
├────────┼──────────────────────┤
│ndim │ number of dimensions │
├────────┼──────────────────────┤
│periods │ periodicity │
├────────┼──────────────────────┤
│topo │ topology information │
└────────┴──────────────────────┘
Methods Documentation
Get_cart_rank(coords)
Translate logical coordinates to ranks
Parameters
coords (Sequence[int]) –
Return type
int
Get_coords(rank)
Translate ranks to logical coordinates
Parameters
rank (int) –
Return type
List[int]
Get_dim()
Return number of dimensions
Return type
int
Get_topo()
Return information on the cartesian topology
Return type
Tuple[List[int], List[int], List[int]]
Shift(direction, disp)
Return a tuple (source, dest) of process ranks for data
shifting with Comm.Sendrecv()
Parameters
• direction (int) –
• disp (int) –
Return type
Tuple[int, int]
Sub(remain_dims)
Return cartesian communicators that form lower-dimen-
sional subgrids
Parameters
remain_dims (Sequence[bool]) –
Return type
Cartcomm
Attributes Documentation
coords coordinates
dim number of dimensions
dims dimensions
ndim number of dimensions
periods
periodicity
topo topology information
mpi4py.MPI.Comm
class mpi4py.MPI.Comm(comm=None)
Bases: object
Communicator
Parameters
comm (Optional[Comm]) –
Return type
Comm
static __new__(cls, comm=None)
Parameters
comm (Optional[Comm]) –
Return type
Comm
Methods Summary
┌───────────────────────────────┬────────────────────────────┐
│Abort([errorcode]) │ Terminate MPI execution │
│ │ environment │
├───────────────────────────────┼────────────────────────────┤
│Allgather(sendbuf, │ Gather to All, gather data │
│recvbuf) │ from all processes and │
│ │ distribute it to all other │
│ │ processes in a group │
├───────────────────────────────┼────────────────────────────┤
│Allgatherv(sendbuf, │ Gather to All Vector, │
│recvbuf) │ gather data from all pro- │
│ │ cesses and distribute it │
│ │ to all other processes in │
│ │ a group providing differ- │
│ │ ent amount of data and │
│ │ displacements │
├───────────────────────────────┼────────────────────────────┤
│Allreduce(sendbuf, │ Reduce to All │
│recvbuf[, op]) │ │
├───────────────────────────────┼────────────────────────────┤
│Alltoall(sendbuf, recvbuf) │ All to All Scatter/Gather, │
│ │ send data from all to all │
│ │ processes in a group │
├───────────────────────────────┼────────────────────────────┤
│Alltoallv(sendbuf, │ All to All Scatter/Gather │
│recvbuf) │ Vector, send data from all │
│ │ to all processes in a │
│ │ group providing different │
│ │ amount of data and dis- │
│ │ placements │
├───────────────────────────────┼────────────────────────────┤
│Alltoallw(sendbuf, │ Generalized All-to-All │
│recvbuf) │ communication allowing │
│ │ different counts, dis- │
│ │ placements and datatypes │
│ │ for each partner │
├───────────────────────────────┼────────────────────────────┤
│Barrier() │ Barrier synchronization │
├───────────────────────────────┼────────────────────────────┤
│Bcast(buf[, root]) │ Broadcast a message from │
│ │ one process to all other │
│ │ processes in a group │
├───────────────────────────────┼────────────────────────────┤
│Bsend(buf, dest[, tag]) │ Blocking send in buffered │
│ │ mode │
├───────────────────────────────┼────────────────────────────┤
│Bsend_init(buf, dest[, │ Persistent request for a │
│tag]) │ send in buffered mode │
├───────────────────────────────┼────────────────────────────┤
│Call_errhandler(errorcode) │ Call the error handler in- │
│ │ stalled on a communicator │
├───────────────────────────────┼────────────────────────────┤
│Clone() │ Clone an existing communi- │
│ │ cator │
├───────────────────────────────┼────────────────────────────┤
│Compare(comm1, comm2) │ Compare two communicators │
├───────────────────────────────┼────────────────────────────┤
│Create(group) │ Create communicator from │
│ │ group │
├───────────────────────────────┼────────────────────────────┤
│Create_group(group[, tag]) │ Create communicator from │
│ │ group │
└───────────────────────────────┴────────────────────────────┘
│Create_keyval([copy_fn, │ Create a new attribute key │
│delete_fn, nopython]) │ for communicators │
├───────────────────────────────┼────────────────────────────┤
│Delete_attr(keyval) │ Delete attribute value as- │
│ │ sociated with a key │
├───────────────────────────────┼────────────────────────────┤
│Disconnect() │ Disconnect from a communi- │
│ │ cator │
├───────────────────────────────┼────────────────────────────┤
│Dup([info]) │ Duplicate an existing com- │
│ │ municator │
├───────────────────────────────┼────────────────────────────┤
│Dup_with_info(info) │ Duplicate an existing com- │
│ │ municator │
├───────────────────────────────┼────────────────────────────┤
│Free() │ Free a communicator │
├───────────────────────────────┼────────────────────────────┤
│Free_keyval(keyval) │ Free an attribute key for │
│ │ communicators │
├───────────────────────────────┼────────────────────────────┤
│Gather(sendbuf, recvbuf[, │ Gather together values │
│root]) │ from a group of processes │
├───────────────────────────────┼────────────────────────────┤
│Gatherv(sendbuf, recvbuf[, │ Gather Vector, gather data │
│root]) │ to one process from all │
│ │ other processes in a group │
│ │ providing different amount │
│ │ of data and displacements │
│ │ at the receiving sides │
├───────────────────────────────┼────────────────────────────┤
│Get_attr(keyval) │ Retrieve attribute value │
│ │ by key │
├───────────────────────────────┼────────────────────────────┤
│Get_errhandler() │ Get the error handler for │
│ │ a communicator │
├───────────────────────────────┼────────────────────────────┤
│Get_group() │ Access the group associ- │
│ │ ated with a communicator │
├───────────────────────────────┼────────────────────────────┤
│Get_info() │ Return the hints for a │
│ │ communicator that are cur- │
│ │ rently in use │
├───────────────────────────────┼────────────────────────────┤
│Get_name() │ Get the print name for │
│ │ this communicator │
├───────────────────────────────┼────────────────────────────┤
│Get_parent() │ Return the parent inter- │
│ │ communicator for this │
│ │ process │
├───────────────────────────────┼────────────────────────────┤
│Get_rank() │ Return the rank of this │
│ │ process in a communicator │
├───────────────────────────────┼────────────────────────────┤
│Get_size() │ Return the number of pro- │
│ │ cesses in a communicator │
├───────────────────────────────┼────────────────────────────┤
│Get_topology() │ Determine the type of │
│ │ topology (if any) associ- │
│ │ ated with a communicator │
├───────────────────────────────┼────────────────────────────┤
│Iallgather(sendbuf, │ Nonblocking Gather to All │
│recvbuf) │ │
├───────────────────────────────┼────────────────────────────┤
│Iallgatherv(sendbuf, │ Nonblocking Gather to All │
│recvbuf) │ Vector │
├───────────────────────────────┼────────────────────────────┤
│Iallreduce(sendbuf, │ Nonblocking Reduce to All │
│recvbuf[, op]) │ │
├───────────────────────────────┼────────────────────────────┤
│Ialltoall(sendbuf, │ Nonblocking All to All │
│recvbuf) │ Scatter/Gather │
├───────────────────────────────┼────────────────────────────┤
│Ialltoallv(sendbuf, │ Nonblocking All to All │
│recvbuf) │ Scatter/Gather Vector │
├───────────────────────────────┼────────────────────────────┤
│Ialltoallw(sendbuf, │ Nonblocking Generalized │
│recvbuf) │ All-to-All │
└───────────────────────────────┴────────────────────────────┘
│Ibarrier() │ Nonblocking Barrier │
├───────────────────────────────┼────────────────────────────┤
│Ibcast(buf[, root]) │ Nonblocking Broadcast │
├───────────────────────────────┼────────────────────────────┤
│Ibsend(buf, dest[, tag]) │ Nonblocking send in │
│ │ buffered mode │
├───────────────────────────────┼────────────────────────────┤
│Idup() │ Nonblocking duplicate an │
│ │ existing communicator │
├───────────────────────────────┼────────────────────────────┤
│Igather(sendbuf, recvbuf[, │ Nonblocking Gather │
│root]) │ │
├───────────────────────────────┼────────────────────────────┤
│Igatherv(sendbuf, │ Nonblocking Gather Vector │
│recvbuf[, root]) │ │
├───────────────────────────────┼────────────────────────────┤
│Improbe([source, tag, sta- │ Nonblocking test for a │
│tus]) │ matched message │
├───────────────────────────────┼────────────────────────────┤
│Iprobe([source, tag, sta- │ Nonblocking test for a │
│tus]) │ message │
├───────────────────────────────┼────────────────────────────┤
│Irecv(buf[, source, tag]) │ Nonblocking receive │
├───────────────────────────────┼────────────────────────────┤
│Ireduce(sendbuf, recvbuf[, │ Nonblocking Reduce to Root │
│op, root]) │ │
├───────────────────────────────┼────────────────────────────┤
│Ireduce_scatter(sendbuf, │ Nonblocking Reduce-Scatter │
│recvbuf[, ...]) │ (vector version) │
├───────────────────────────────┼────────────────────────────┤
│Ireduce_scatter_block(sendbuf, │ Nonblocking Reduce-Scatter │
│recvbuf[, op]) │ Block (regular, non-vector │
│ │ version) │
├───────────────────────────────┼────────────────────────────┤
│Irsend(buf, dest[, tag]) │ Nonblocking send in ready │
│ │ mode │
├───────────────────────────────┼────────────────────────────┤
│Is_inter() │ Test to see if a comm is │
│ │ an intercommunicator │
├───────────────────────────────┼────────────────────────────┤
│Is_intra() │ Test to see if a comm is │
│ │ an intracommunicator │
├───────────────────────────────┼────────────────────────────┤
│Iscatter(sendbuf, recvbuf[, │ Nonblocking Scatter │
│root]) │ │
├───────────────────────────────┼────────────────────────────┤
│Iscatterv(sendbuf, recvbuf[, │ Nonblocking Scatter Vector │
│root]) │ │
├───────────────────────────────┼────────────────────────────┤
│Isend(buf, dest[, tag]) │ Nonblocking send │
├───────────────────────────────┼────────────────────────────┤
│Issend(buf, dest[, tag]) │ Nonblocking send in syn- │
│ │ chronous mode │
├───────────────────────────────┼────────────────────────────┤
│Join(fd) │ Create a intercommunicator │
│ │ by joining two processes │
│ │ connected by a socket │
├───────────────────────────────┼────────────────────────────┤
│Mprobe([source, tag, status]) │ Blocking test for a │
│ │ matched message │
├───────────────────────────────┼────────────────────────────┤
│Probe([source, tag, status]) │ Blocking test for a mes- │
│ │ sage │
├───────────────────────────────┼────────────────────────────┤
│Recv(buf[, source, tag, sta- │ Blocking receive │
│tus]) │ │
├───────────────────────────────┼────────────────────────────┤
│Recv_init(buf[, source, tag]) │ Create a persistent re- │
│ │ quest for a receive │
├───────────────────────────────┼────────────────────────────┤
│Reduce(sendbuf, recvbuf[, op, │ Reduce to Root │
│root]) │ │
├───────────────────────────────┼────────────────────────────┤
│Reduce_scatter(sendbuf, │ Reduce-Scatter (vector │
│recvbuf[, ...]) │ version) │
└───────────────────────────────┴────────────────────────────┘
│Reduce_scatter_block(sendbuf, │ Reduce-Scatter Block (reg- │
│recvbuf[, op]) │ ular, non-vector version) │
├───────────────────────────────┼────────────────────────────┤
│Rsend(buf, dest[, tag]) │ Blocking send in ready │
│ │ mode │
├───────────────────────────────┼────────────────────────────┤
│Rsend_init(buf, dest[, tag]) │ Persistent request for a │
│ │ send in ready mode │
├───────────────────────────────┼────────────────────────────┤
│Scatter(sendbuf, recvbuf[, │ Scatter data from one │
│root]) │ process to all other pro- │
│ │ cesses in a group │
├───────────────────────────────┼────────────────────────────┤
│Scatterv(sendbuf, recvbuf[, │ Scatter Vector, scatter │
│root]) │ data from one process to │
│ │ all other processes in a │
│ │ group providing different │
│ │ amount of data and dis- │
│ │ placements at the sending │
│ │ side │
├───────────────────────────────┼────────────────────────────┤
│Send(buf, dest[, tag]) │ Blocking send │
├───────────────────────────────┼────────────────────────────┤
│Send_init(buf, dest[, tag]) │ Create a persistent re- │
│ │ quest for a standard send │
├───────────────────────────────┼────────────────────────────┤
│Sendrecv(sendbuf, dest[, send- │ Send and receive a message │
│tag, recvbuf, ...]) │ │
├───────────────────────────────┼────────────────────────────┤
│Sendrecv_replace(buf, dest[, │ Send and receive a message │
│sendtag, ...]) │ │
├───────────────────────────────┼────────────────────────────┤
│Set_attr(keyval, attrval) │ Store attribute value as- │
│ │ sociated with a key │
├───────────────────────────────┼────────────────────────────┤
│Set_errhandler(errhandler) │ Set the error handler for │
│ │ a communicator │
├───────────────────────────────┼────────────────────────────┤
│Set_info(info) │ Set new values for the │
│ │ hints associated with a │
│ │ communicator │
├───────────────────────────────┼────────────────────────────┤
│Set_name(name) │ Set the print name for │
│ │ this communicator │
├───────────────────────────────┼────────────────────────────┤
│Split([color, key]) │ Split communicator by │
│ │ color and key │
├───────────────────────────────┼────────────────────────────┤
│Split_type(split_type[, key, │ Split communicator by │
│info]) │ split type │
├───────────────────────────────┼────────────────────────────┤
│Ssend(buf, dest[, tag]) │ Blocking send in synchro- │
│ │ nous mode │
├───────────────────────────────┼────────────────────────────┤
│Ssend_init(buf, dest[, tag]) │ Persistent request for a │
│ │ send in synchronous mode │
├───────────────────────────────┼────────────────────────────┤
│allgather(sendobj) │ Gather to All │
├───────────────────────────────┼────────────────────────────┤
│allreduce(sendobj[, op]) │ Reduce to All │
├───────────────────────────────┼────────────────────────────┤
│alltoall(sendobj) │ All to All Scatter/Gather │
├───────────────────────────────┼────────────────────────────┤
│barrier() │ Barrier │
├───────────────────────────────┼────────────────────────────┤
│bcast(obj[, root]) │ Broadcast │
├───────────────────────────────┼────────────────────────────┤
│bsend(obj, dest[, tag]) │ Send in buffered mode │
├───────────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────────┼────────────────────────────┤
│gather(sendobj[, root]) │ Gather │
├───────────────────────────────┼────────────────────────────┤
│ibsend(obj, dest[, tag]) │ Nonblocking send in │
│ │ buffered mode │
└───────────────────────────────┴────────────────────────────┘
│improbe([source, tag, status]) │ Nonblocking test for a │
│ │ matched message │
├───────────────────────────────┼────────────────────────────┤
│iprobe([source, tag, status]) │ Nonblocking test for a │
│ │ message │
├───────────────────────────────┼────────────────────────────┤
│irecv([buf, source, tag]) │ Nonblocking receive │
├───────────────────────────────┼────────────────────────────┤
│isend(obj, dest[, tag]) │ Nonblocking send │
├───────────────────────────────┼────────────────────────────┤
│issend(obj, dest[, tag]) │ Nonblocking send in syn- │
│ │ chronous mode │
├───────────────────────────────┼────────────────────────────┤
│mprobe([source, tag, status]) │ Blocking test for a │
│ │ matched message │
├───────────────────────────────┼────────────────────────────┤
│probe([source, tag, status]) │ Blocking test for a mes- │
│ │ sage │
├───────────────────────────────┼────────────────────────────┤
│py2f() │ │
├───────────────────────────────┼────────────────────────────┤
│recv([buf, source, tag, sta- │ Receive │
│tus]) │ │
├───────────────────────────────┼────────────────────────────┤
│reduce(sendobj[, op, root]) │ Reduce to Root │
├───────────────────────────────┼────────────────────────────┤
│scatter(sendobj[, root]) │ Scatter │
├───────────────────────────────┼────────────────────────────┤
│send(obj, dest[, tag]) │ Send │
├───────────────────────────────┼────────────────────────────┤
│sendrecv(sendobj, dest[, send- │ Send and Receive │
│tag, recvbuf, ...]) │ │
├───────────────────────────────┼────────────────────────────┤
│ssend(obj, dest[, tag]) │ Send in synchronous mode │
└───────────────────────────────┴────────────────────────────┘
Attributes Summary
┌─────────┬────────────────────────────┐
│group │ communicator group │
├─────────┼────────────────────────────┤
│info │ communicator info │
├─────────┼────────────────────────────┤
│is_inter │ is intercommunicator │
├─────────┼────────────────────────────┤
│is_intra │ is intracommunicator │
├─────────┼────────────────────────────┤
│is_topo │ is a topology communicator │
├─────────┼────────────────────────────┤
│name │ communicator name │
├─────────┼────────────────────────────┤
│rank │ rank of this process in │
│ │ communicator │
├─────────┼────────────────────────────┤
│size │ number of processes in │
│ │ communicator │
├─────────┼────────────────────────────┤
│topology │ communicator topology type │
└─────────┴────────────────────────────┘
Methods Documentation
Abort(errorcode=0)
Terminate MPI execution environment
WARNING:
This is a direct call, use it with care!!!.
Parameters
errorcode (int) –
Return type
NoReturn
Allgather(sendbuf, recvbuf)
Gather to All, gather data from all processes and dis-
tribute it to all other processes in a group
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpecB) –
Return type
None
Allgatherv(sendbuf, recvbuf)
Gather to All Vector, gather data from all processes and
distribute it to all other processes in a group providing
different amount of data and displacements
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpecV) –
Return type
None
Allreduce(sendbuf, recvbuf, op=SUM)
Reduce to All
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• op (Op) –
Return type
None
Alltoall(sendbuf, recvbuf)
All to All Scatter/Gather, send data from all to all pro-
cesses in a group
Parameters
• sendbuf (Union[BufSpecB, InPlace]) –
• recvbuf (BufSpecB) –
Return type
None
Alltoallv(sendbuf, recvbuf)
All to All Scatter/Gather Vector, send data from all to
all processes in a group providing different amount of
data and displacements
Parameters
• sendbuf (Union[BufSpecV, InPlace]) –
• recvbuf (BufSpecV) –
Return type
None
Alltoallw(sendbuf, recvbuf)
Generalized All-to-All communication allowing different
counts, displacements and datatypes for each partner
Parameters
• sendbuf (Union[BufSpecW, InPlace]) –
• recvbuf (BufSpecW) –
Return type
None
Barrier()
Barrier synchronization
Return type
None
Bcast(buf, root=0)
Broadcast a message from one process to all other pro-
cesses in a group
Parameters
• buf (BufSpec) –
• root (int) –
Return type
None
Bsend(buf, dest, tag=0)
Blocking send in buffered mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
None
Bsend_init(buf, dest, tag=0)
Persistent request for a send in buffered mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Request
Call_errhandler(errorcode)
Call the error handler installed on a communicator
Parameters
errorcode (int) –
Return type
None
Clone()
Clone an existing communicator
Return type
Comm
classmethod Compare(comm1, comm2)
Compare two communicators
Parameters
• comm1 (Comm) –
• comm2 (Comm) –
Return type
int
Create(group)
Create communicator from group
Parameters
group (Group) –
Return type
Comm
Create_group(group, tag=0)
Create communicator from group
Parameters
• group (Group) –
• tag (int) –
Return type
Comm
classmethod Create_keyval(copy_fn=None, delete_fn=None, nopy-
thon=False)
Create a new attribute key for communicators
Parameters
• copy_fn (Optional[Callable[[Comm, int, Any],
Any]]) –
• delete_fn (Optional[Callable[[Comm, int, Any],
None]]) –
• nopython (bool) –
Return type
int
Delete_attr(keyval)
Delete attribute value associated with a key
Parameters
keyval (int) –
Return type
None
Disconnect()
Disconnect from a communicator
Return type
None
Dup(info=None)
Duplicate an existing communicator
Parameters
info (Optional[Info]) –
Return type
Comm
Dup_with_info(info)
Duplicate an existing communicator
Parameters
info (Info) –
Return type
Comm
Free() Free a communicator
Return type
None
classmethod Free_keyval(keyval)
Free an attribute key for communicators
Parameters
keyval (int) –
Return type
int
Gather(sendbuf, recvbuf, root=0)
Gather together values from a group of processes
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (Optional[BufSpecB]) –
• root (int) –
Return type
None
Gatherv(sendbuf, recvbuf, root=0)
Gather Vector, gather data to one process from all other
processes in a group providing different amount of data
and displacements at the receiving sides
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (Optional[BufSpecV]) –
• root (int) –
Return type
None
Get_attr(keyval)
Retrieve attribute value by key
Parameters
keyval (int) –
Return type
Optional[Union[int, Any]]
Get_errhandler()
Get the error handler for a communicator
Return type
Errhandler
Get_group()
Access the group associated with a communicator
Return type
Group
Get_info()
Return the hints for a communicator that are currently in
use
Return type
Info
Get_name()
Get the print name for this communicator
Return type
str
classmethod Get_parent()
Return the parent intercommunicator for this process
Return type
Intercomm
Get_rank()
Return the rank of this process in a communicator
Return type
int
Get_size()
Return the number of processes in a communicator
Return type
int
Get_topology()
Determine the type of topology (if any) associated with a
communicator
Return type
int
Iallgather(sendbuf, recvbuf)
Nonblocking Gather to All
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpecB) –
Return type
Request
Iallgatherv(sendbuf, recvbuf)
Nonblocking Gather to All Vector
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpecV) –
Return type
Request
Iallreduce(sendbuf, recvbuf, op=SUM)
Nonblocking Reduce to All
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• op (Op) –
Return type
Request
Ialltoall(sendbuf, recvbuf)
Nonblocking All to All Scatter/Gather
Parameters
• sendbuf (Union[BufSpecB, InPlace]) –
• recvbuf (BufSpecB) –
Return type
Request
Ialltoallv(sendbuf, recvbuf)
Nonblocking All to All Scatter/Gather Vector
Parameters
• sendbuf (Union[BufSpecV, InPlace]) –
• recvbuf (BufSpecV) –
Return type
Request
Ialltoallw(sendbuf, recvbuf)
Nonblocking Generalized All-to-All
Parameters
• sendbuf (Union[BufSpecW, InPlace]) –
• recvbuf (BufSpecW) –
Return type
Request
Ibarrier()
Nonblocking Barrier
Return type
Request
Ibcast(buf, root=0)
Nonblocking Broadcast
Parameters
• buf (BufSpec) –
• root (int) –
Return type
Request
Ibsend(buf, dest, tag=0)
Nonblocking send in buffered mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Request
Idup() Nonblocking duplicate an existing communicator
Return type
Tuple[Comm, Request]
Igather(sendbuf, recvbuf, root=0)
Nonblocking Gather
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (Optional[BufSpecB]) –
• root (int) –
Return type
Request
Igatherv(sendbuf, recvbuf, root=0)
Nonblocking Gather Vector
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (Optional[BufSpecV]) –
• root (int) –
Return type
Request
Improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Optional[Message]
Iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a message
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
bool
Irecv(buf, source=ANY_SOURCE, tag=ANY_TAG)
Nonblocking receive
Parameters
• buf (BufSpec) –
• source (int) –
• tag (int) –
Return type
Request
Ireduce(sendbuf, recvbuf, op=SUM, root=0)
Nonblocking Reduce to Root
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (Optional[BufSpec]) –
• op (Op) –
• root (int) –
Return type
Request
Ireduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)
Nonblocking Reduce-Scatter (vector version)
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• recvcounts (Optional[Sequence[int]]) –
• op (Op) –
Return type
Request
Ireduce_scatter_block(sendbuf, recvbuf, op=SUM)
Nonblocking Reduce-Scatter Block (regular, non-vector
version)
Parameters
• sendbuf (Union[BufSpecB, InPlace]) –
• recvbuf (Union[BufSpec, BufSpecB]) –
• op (Op) –
Return type
Request
Irsend(buf, dest, tag=0)
Nonblocking send in ready mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Request
Is_inter()
Test to see if a comm is an intercommunicator
Return type
bool
Is_intra()
Test to see if a comm is an intracommunicator
Return type
bool
Iscatter(sendbuf, recvbuf, root=0)
Nonblocking Scatter
Parameters
• sendbuf (Optional[BufSpecB]) –
• recvbuf (Union[BufSpec, InPlace]) –
• root (int) –
Return type
Request
Iscatterv(sendbuf, recvbuf, root=0)
Nonblocking Scatter Vector
Parameters
• sendbuf (Optional[BufSpecV]) –
• recvbuf (Union[BufSpec, InPlace]) –
• root (int) –
Return type
Request
Isend(buf, dest, tag=0)
Nonblocking send
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Request
Issend(buf, dest, tag=0)
Nonblocking send in synchronous mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Request
classmethod Join(fd)
Create a intercommunicator by joining two processes con-
nected by a socket
Parameters
fd (int) –
Return type
Intercomm
Mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Message
Probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a message
NOTE:
This function blocks until the message arrives.
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Literal[True]
Recv(buf, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking receive
NOTE:
This function blocks until the message is received
Parameters
• buf (BufSpec) –
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
None
Recv_init(buf, source=ANY_SOURCE, tag=ANY_TAG)
Create a persistent request for a receive
Parameters
• buf (BufSpec) –
• source (int) –
• tag (int) –
Return type
Prequest
Reduce(sendbuf, recvbuf, op=SUM, root=0)
Reduce to Root
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (Optional[BufSpec]) –
• op (Op) –
• root (int) –
Return type
None
Reduce_scatter(sendbuf, recvbuf, recvcounts=None, op=SUM)
Reduce-Scatter (vector version)
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• recvcounts (Optional[Sequence[int]]) –
• op (Op) –
Return type
None
Reduce_scatter_block(sendbuf, recvbuf, op=SUM)
Reduce-Scatter Block (regular, non-vector version)
Parameters
• sendbuf (Union[BufSpecB, InPlace]) –
• recvbuf (Union[BufSpec, BufSpecB]) –
• op (Op) –
Return type
None
Rsend(buf, dest, tag=0)
Blocking send in ready mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
None
Rsend_init(buf, dest, tag=0)
Persistent request for a send in ready mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Request
Scatter(sendbuf, recvbuf, root=0)
Scatter data from one process to all other processes in a
group
Parameters
• sendbuf (Optional[BufSpecB]) –
• recvbuf (Union[BufSpec, InPlace]) –
• root (int) –
Return type
None
Scatterv(sendbuf, recvbuf, root=0)
Scatter Vector, scatter data from one process to all
other processes in a group providing different amount of
data and displacements at the sending side
Parameters
• sendbuf (Optional[BufSpecV]) –
• recvbuf (Union[BufSpec, InPlace]) –
• root (int) –
Return type
None
Send(buf, dest, tag=0)
Blocking send
NOTE:
This function may block until the message is received.
Whether or not Send blocks depends on several factors
and is implementation dependent
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
None
Send_init(buf, dest, tag=0)
Create a persistent request for a standard send
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Prequest
Sendrecv(sendbuf, dest, sendtag=0, recvbuf=None,
source=ANY_SOURCE, recvtag=ANY_TAG, status=None)
Send and receive a message
NOTE:
This function is guaranteed not to deadlock in situa-
tions where pairs of blocking sends and receives may
deadlock.
CAUTION:
A common mistake when using this function is to mis-
match the tags with the source and destination ranks,
which can result in deadlock.
Parameters
• sendbuf (BufSpec) –
• dest (int) –
• sendtag (int) –
• recvbuf (BufSpec) –
• source (int) –
• recvtag (int) –
• status (Optional[Status]) –
Return type
None
Sendrecv_replace(buf, dest, sendtag=0, source=ANY_SOURCE, recv-
tag=ANY_TAG, status=None)
Send and receive a message
NOTE:
This function is guaranteed not to deadlock in situa-
tions where pairs of blocking sends and receives may
deadlock.
CAUTION:
A common mistake when using this function is to mis-
match the tags with the source and destination ranks,
which can result in deadlock.
Parameters
• buf (BufSpec) –
• dest (int) –
• sendtag (int) –
• source (int) –
• recvtag (int) –
• status (Optional[Status]) –
Return type
None
Set_attr(keyval, attrval)
Store attribute value associated with a key
Parameters
• keyval (int) –
• attrval (Any) –
Return type
None
Set_errhandler(errhandler)
Set the error handler for a communicator
Parameters
errhandler (Errhandler) –
Return type
None
Set_info(info)
Set new values for the hints associated with a communica-
tor
Parameters
info (Info) –
Return type
None
Set_name(name)
Set the print name for this communicator
Parameters
name (str) –
Return type
None
Split(color=0, key=0)
Split communicator by color and key
Parameters
• color (int) –
• key (int) –
Return type
Comm
Split_type(split_type, key=0, info=INFO_NULL)
Split communicator by split type
Parameters
• split_type (int) –
• key (int) –
• info (Info) –
Return type
Comm
Ssend(buf, dest, tag=0)
Blocking send in synchronous mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
None
Ssend_init(buf, dest, tag=0)
Persistent request for a send in synchronous mode
Parameters
• buf (BufSpec) –
• dest (int) –
• tag (int) –
Return type
Request
allgather(sendobj)
Gather to All
Parameters
sendobj (Any) –
Return type
List[Any]
allreduce(sendobj, op=SUM)
Reduce to All
Parameters
• sendobj (Any) –
• op (Union[Op, Callable[[Any, Any], Any]]) –
Return type
Any
alltoall(sendobj)
All to All Scatter/Gather
Parameters
sendobj (Sequence[Any]) –
Return type
List[Any]
barrier()
Barrier
Return type
None
bcast(obj, root=0)
Broadcast
Parameters
• obj (Any) –
• root (int) –
Return type
Any
bsend(obj, dest, tag=0)
Send in buffered mode
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
None
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Comm
gather(sendobj, root=0)
Gather
Parameters
• sendobj (Any) –
• root (int) –
Return type
Optional[List[Any]]
ibsend(obj, dest, tag=0)
Nonblocking send in buffered mode
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
Request
improbe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a matched message
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Optional[Message]
iprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Nonblocking test for a message
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
bool
irecv(buf=None, source=ANY_SOURCE, tag=ANY_TAG)
Nonblocking receive
Parameters
• buf (Optional[Buffer]) –
• source (int) –
• tag (int) –
Return type
Request
isend(obj, dest, tag=0)
Nonblocking send
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
Request
issend(obj, dest, tag=0)
Nonblocking send in synchronous mode
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
Request
mprobe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a matched message
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Message
probe(source=ANY_SOURCE, tag=ANY_TAG, status=None)
Blocking test for a message
Parameters
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Literal[True]
py2f()
Return type
int
recv(buf=None, source=ANY_SOURCE, tag=ANY_TAG, status=None)
Receive
Parameters
• buf (Optional[Buffer]) –
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Any
reduce(sendobj, op=SUM, root=0)
Reduce to Root
Parameters
• sendobj (Any) –
• op (Union[Op, Callable[[Any, Any], Any]]) –
• root (int) –
Return type
Optional[Any]
scatter(sendobj, root=0)
Scatter
Parameters
• sendobj (Sequence[Any]) –
• root (int) –
Return type
Any
send(obj, dest, tag=0)
Send
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
None
sendrecv(sendobj, dest, sendtag=0, recvbuf=None,
source=ANY_SOURCE, recvtag=ANY_TAG, status=None)
Send and Receive
Parameters
• sendobj (Any) –
• dest (int) –
• sendtag (int) –
• recvbuf (Optional[Buffer]) –
• source (int) –
• recvtag (int) –
• status (Optional[Status]) –
Return type
Any
ssend(obj, dest, tag=0)
Send in synchronous mode
Parameters
• obj (Any) –
• dest (int) –
• tag (int) –
Return type
None
Attributes Documentation
group communicator group
info communicator info
is_inter
is intercommunicator
is_intra
is intracommunicator
is_topo
is a topology communicator
name communicator name
rank rank of this process in communicator
size number of processes in communicator
topology
communicator topology type
mpi4py.MPI.Datatype
class mpi4py.MPI.Datatype(datatype=None)
Bases: object
Datatype object
Parameters
datatype (Optional[Datatype]) –
Return type
Datatype
static __new__(cls, datatype=None)
Parameters
datatype (Optional[Datatype]) –
Return type
Datatype
Methods Summary
┌───────────────────────────────────┬────────────────────────────┐
│Commit() │ Commit the datatype │
├───────────────────────────────────┼────────────────────────────┤
│Create_contiguous(count) │ Create a contiguous │
│ │ datatype │
├───────────────────────────────────┼────────────────────────────┤
│Create_darray(size, rank, │ Create a datatype repre- │
│gsizes, distribs, ...) │ senting an HPF-like dis- │
│ │ tributed array on Carte- │
│ │ sian process grids │
├───────────────────────────────────┼────────────────────────────┤
│Create_f90_complex(p, r) │ Return a bounded complex │
│ │ datatype │
├───────────────────────────────────┼────────────────────────────┤
│Create_f90_integer(r) │ Return a bounded integer │
│ │ datatype │
└───────────────────────────────────┴────────────────────────────┘
│Create_f90_real(p, r) │ Return a bounded real │
│ │ datatype │
├───────────────────────────────────┼────────────────────────────┤
│Create_hindexed(blocklengths, │ Create an indexed datatype │
│displacements) │ with displacements in │
│ │ bytes │
├───────────────────────────────────┼────────────────────────────┤
│Create_hindexed_block(blocklength, │ Create an indexed datatype │
│displacements) │ with constant-sized blocks │
│ │ and displacements in bytes │
├───────────────────────────────────┼────────────────────────────┤
│Create_hvector(count, blocklength, │ Create a vector (strided) │
│stride) │ datatype │
├───────────────────────────────────┼────────────────────────────┤
│Create_indexed(blocklengths, dis- │ Create an indexed datatype │
│placements) │ │
├───────────────────────────────────┼────────────────────────────┤
│Create_indexed_block(blocklength, │ Create an indexed datatype │
│displacements) │ with constant-sized blocks │
├───────────────────────────────────┼────────────────────────────┤
│Create_keyval([copy_fn, delete_fn, │ Create a new attribute key │
│nopython]) │ for datatypes │
├───────────────────────────────────┼────────────────────────────┤
│Create_resized(lb, extent) │ Create a datatype with a │
│ │ new lower bound and extent │
├───────────────────────────────────┼────────────────────────────┤
│Create_struct(blocklengths, dis- │ Create an datatype from a │
│placements, ...) │ general set of block │
│ │ sizes, displacements and │
│ │ datatypes │
├───────────────────────────────────┼────────────────────────────┤
│Create_subarray(sizes, subsizes, │ Create a datatype for a │
│starts[, order]) │ subarray of a regular, │
│ │ multidimensional array │
├───────────────────────────────────┼────────────────────────────┤
│Create_vector(count, blocklength, │ Create a vector (strided) │
│stride) │ datatype │
├───────────────────────────────────┼────────────────────────────┤
│Delete_attr(keyval) │ Delete attribute value as- │
│ │ sociated with a key │
├───────────────────────────────────┼────────────────────────────┤
│Dup() │ Duplicate a datatype │
├───────────────────────────────────┼────────────────────────────┤
│Free() │ Free the datatype │
├───────────────────────────────────┼────────────────────────────┤
│Free_keyval(keyval) │ Free an attribute key for │
│ │ datatypes │
├───────────────────────────────────┼────────────────────────────┤
│Get_attr(keyval) │ Retrieve attribute value │
│ │ by key │
├───────────────────────────────────┼────────────────────────────┤
│Get_contents() │ Retrieve the actual argu- │
│ │ ments used in the call │
│ │ that created a datatype │
├───────────────────────────────────┼────────────────────────────┤
│Get_envelope() │ Return information on the │
│ │ number and type of input │
│ │ arguments used in the call │
│ │ that created a datatype │
├───────────────────────────────────┼────────────────────────────┤
│Get_extent() │ Return lower bound and ex- │
│ │ tent of datatype │
├───────────────────────────────────┼────────────────────────────┤
│Get_name() │ Get the print name for │
│ │ this datatype │
├───────────────────────────────────┼────────────────────────────┤
│Get_size() │ Return the number of bytes │
│ │ occupied by entries in the │
│ │ datatype │
├───────────────────────────────────┼────────────────────────────┤
│Get_true_extent() │ Return the true lower │
│ │ bound and extent of a │
│ │ datatype │
├───────────────────────────────────┼────────────────────────────┤
│Match_size(typeclass, size) │ Find a datatype matching a │
│ │ specified size in bytes │
├───────────────────────────────────┼────────────────────────────┤
│Pack(inbuf, outbuf, position, │ Pack into contiguous mem- │
│comm) │ ory according to datatype. │
├───────────────────────────────────┼────────────────────────────┤
│Pack_external(datarep, inbuf, out- │ Pack into contiguous mem- │
│buf, position) │ ory according to datatype, │
│ │ using a portable data rep- │
│ │ resentation (external32). │
├───────────────────────────────────┼────────────────────────────┤
│Pack_external_size(datarep, count) │ Return the upper bound on │
│ │ the amount of space (in │
│ │ bytes) needed to pack a │
│ │ message according to │
│ │ datatype, using a portable │
│ │ data representation (ex- │
│ │ ternal32). │
└───────────────────────────────────┴────────────────────────────┘
│Pack_size(count, comm) │ Return the upper bound on │
│ │ the amount of space (in │
│ │ bytes) needed to pack a │
│ │ message according to │
│ │ datatype. │
├───────────────────────────────────┼────────────────────────────┤
│Set_attr(keyval, attrval) │ Store attribute value as- │
│ │ sociated with a key │
├───────────────────────────────────┼────────────────────────────┤
│Set_name(name) │ Set the print name for │
│ │ this datatype │
├───────────────────────────────────┼────────────────────────────┤
│Unpack(inbuf, position, outbuf, │ Unpack from contiguous │
│comm) │ memory according to │
│ │ datatype. │
├───────────────────────────────────┼────────────────────────────┤
│Unpack_external(datarep, inbuf, │ Unpack from contiguous │
│position, outbuf) │ memory according to │
│ │ datatype, using a portable │
│ │ data representation (ex- │
│ │ ternal32). │
├───────────────────────────────────┼────────────────────────────┤
│decode() │ Convenience method for de- │
│ │ coding a datatype │
├───────────────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────────────┼────────────────────────────┤
│py2f() │ │
└───────────────────────────────────┴────────────────────────────┘
Attributes Summary
┌──────────────┬──────────────────────────┐
│combiner │ datatype combiner │
├──────────────┼──────────────────────────┤
│contents │ datatype contents │
├──────────────┼──────────────────────────┤
│envelope │ datatype envelope │
├──────────────┼──────────────────────────┤
│extent │ │
├──────────────┼──────────────────────────┤
│is_named │ is a named datatype │
├──────────────┼──────────────────────────┤
│is_predefined │ is a predefined datatype │
├──────────────┼──────────────────────────┤
│lb │ lower bound │
├──────────────┼──────────────────────────┤
│name │ datatype name │
├──────────────┼──────────────────────────┤
│size │ │
├──────────────┼──────────────────────────┤
│true_extent │ true extent │
├──────────────┼──────────────────────────┤
│true_lb │ true lower bound │
├──────────────┼──────────────────────────┤
│true_ub │ true upper bound │
├──────────────┼──────────────────────────┤
│ub │ upper bound │
└──────────────┴──────────────────────────┘
Methods Documentation
Commit()
Commit the datatype
Return type
Datatype
Create_contiguous(count)
Create a contiguous datatype
Parameters
count (int) –
Return type
Datatype
Create_darray(size, rank, gsizes, distribs, dargs, psizes, or-
der=ORDER_C)
Create a datatype representing an HPF-like distributed
array on Cartesian process grids
Parameters
• size (int) –
• rank (int) –
• gsizes (Sequence[int]) –
• distribs (Sequence[int]) –
• dargs (Sequence[int]) –
• psizes (Sequence[int]) –
• order (int) –
Return type
Datatype
classmethod Create_f90_complex(p, r)
Return a bounded complex datatype
Parameters
• p (int) –
• r (int) –
Return type
Datatype
classmethod Create_f90_integer(r)
Return a bounded integer datatype
Parameters
r (int) –
Return type
Datatype
classmethod Create_f90_real(p, r)
Return a bounded real datatype
Parameters
• p (int) –
• r (int) –
Return type
Datatype
Create_hindexed(blocklengths, displacements)
Create an indexed datatype with displacements in bytes
Parameters
• blocklengths (Sequence[int]) –
• displacements (Sequence[int]) –
Return type
Datatype
Create_hindexed_block(blocklength, displacements)
Create an indexed datatype with constant-sized blocks and
displacements in bytes
Parameters
• blocklength (int) –
• displacements (Sequence[int]) –
Return type
Datatype
Create_hvector(count, blocklength, stride)
Create a vector (strided) datatype
Parameters
• count (int) –
• blocklength (int) –
• stride (int) –
Return type
Datatype
Create_indexed(blocklengths, displacements)
Create an indexed datatype
Parameters
• blocklengths (Sequence[int]) –
• displacements (Sequence[int]) –
Return type
Datatype
Create_indexed_block(blocklength, displacements)
Create an indexed datatype with constant-sized blocks
Parameters
• blocklength (int) –
• displacements (Sequence[int]) –
Return type
Datatype
classmethod Create_keyval(copy_fn=None, delete_fn=None, nopy-
thon=False)
Create a new attribute key for datatypes
Parameters
• copy_fn (Optional[Callable[[Datatype, int, Any],
Any]]) –
• delete_fn (Optional[Callable[[Datatype, int,
Any], None]]) –
• nopython (bool) –
Return type
int
Create_resized(lb, extent)
Create a datatype with a new lower bound and extent
Parameters
• lb (int) –
• extent (int) –
Return type
Datatype
classmethod Create_struct(blocklengths, displacements,
datatypes)
Create an datatype from a general set of block sizes,
displacements and datatypes
Parameters
• blocklengths (Sequence[int]) –
• displacements (Sequence[int]) –
• datatypes (Sequence[Datatype]) –
Return type
Datatype
Create_subarray(sizes, subsizes, starts, order=ORDER_C)
Create a datatype for a subarray of a regular, multidi-
mensional array
Parameters
• sizes (Sequence[int]) –
• subsizes (Sequence[int]) –
• starts (Sequence[int]) –
• order (int) –
Return type
Datatype
Create_vector(count, blocklength, stride)
Create a vector (strided) datatype
Parameters
• count (int) –
• blocklength (int) –
• stride (int) –
Return type
Datatype
Delete_attr(keyval)
Delete attribute value associated with a key
Parameters
keyval (int) –
Return type
None
Dup() Duplicate a datatype
Return type
Datatype
Free() Free the datatype
Return type
None
classmethod Free_keyval(keyval)
Free an attribute key for datatypes
Parameters
keyval (int) –
Return type
int
Get_attr(keyval)
Retrieve attribute value by key
Parameters
keyval (int) –
Return type
Optional[Union[int, Any]]
Get_contents()
Retrieve the actual arguments used in the call that cre-
ated a datatype
Return type
Tuple[List[int], List[int], List[Datatype]]
Get_envelope()
Return information on the number and type of input argu-
ments used in the call that created a datatype
Return type
Tuple[int, int, int, int]
Get_extent()
Return lower bound and extent of datatype
Return type
Tuple[int, int]
Get_name()
Get the print name for this datatype
Return type
str
Get_size()
Return the number of bytes occupied by entries in the
datatype
Return type
int
Get_true_extent()
Return the true lower bound and extent of a datatype
Return type
Tuple[int, int]
classmethod Match_size(typeclass, size)
Find a datatype matching a specified size in bytes
Parameters
• typeclass (int) –
• size (int) –
Return type
Datatype
Pack(inbuf, outbuf, position, comm)
Pack into contiguous memory according to datatype.
Parameters
• inbuf (BufSpec) –
• outbuf (BufSpec) –
• position (int) –
• comm (Comm) –
Return type
int
Pack_external(datarep, inbuf, outbuf, position)
Pack into contiguous memory according to datatype, using
a portable data representation (external32).
Parameters
• datarep (str) –
• inbuf (BufSpec) –
• outbuf (BufSpec) –
• position (int) –
Return type
int
Pack_external_size(datarep, count)
Return the upper bound on the amount of space (in bytes)
needed to pack a message according to datatype, using a
portable data representation (external32).
Parameters
• datarep (str) –
• count (int) –
Return type
int
Pack_size(count, comm)
Return the upper bound on the amount of space (in bytes)
needed to pack a message according to datatype.
Parameters
• count (int) –
• comm (Comm) –
Return type
int
Set_attr(keyval, attrval)
Store attribute value associated with a key
Parameters
• keyval (int) –
• attrval (Any) –
Return type
None
Set_name(name)
Set the print name for this datatype
Parameters
name (str) –
Return type
None
Unpack(inbuf, position, outbuf, comm)
Unpack from contiguous memory according to datatype.
Parameters
• inbuf (BufSpec) –
• position (int) –
• outbuf (BufSpec) –
• comm (Comm) –
Return type
int
Unpack_external(datarep, inbuf, position, outbuf)
Unpack from contiguous memory according to datatype, us-
ing a portable data representation (external32).
Parameters
• datarep (str) –
• inbuf (BufSpec) –
• position (int) –
• outbuf (BufSpec) –
Return type
int
decode()
Convenience method for decoding a datatype
Return type
Tuple[Datatype, str, Dict[str, Any]]
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Datatype
py2f()
Return type
int
Attributes Documentation
combiner
datatype combiner
contents
datatype contents
envelope
datatype envelope
extent
is_named
is a named datatype
is_predefined
is a predefined datatype
lb lower bound
name datatype name
size
true_extent
true extent
true_lb
true lower bound
true_ub
true upper bound
ub upper bound
mpi4py.MPI.Distgraphcomm
class mpi4py.MPI.Distgraphcomm(comm=None)
Bases: mpi4py.MPI.Topocomm
Distributed graph topology intracommunicator
Parameters
comm (Optional[Distgraphcomm]) –
Return type
Distgraphcomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Distgraphcomm]) –
Return type
Distgraphcomm
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Get_dist_neighbors() │ Return adjacency informa- │
│ │ tion for a distributed │
│ │ graph topology │
├───────────────────────────┼────────────────────────────┤
│Get_dist_neighbors_count() │ Return adjacency informa- │
│ │ tion for a distributed │
│ │ graph topology │
└───────────────────────────┴────────────────────────────┘
Methods Documentation
Get_dist_neighbors()
Return adjacency information for a distributed graph
topology
Return type
Tuple[List[int], List[int], Optional[Tu-
ple[List[int], List[int]]]]
Get_dist_neighbors_count()
Return adjacency information for a distributed graph
topology
Return type
int
mpi4py.MPI.Errhandler
class mpi4py.MPI.Errhandler(errhandler=None)
Bases: object
Error handler
Parameters
errhandler (Optional[Errhandler]) –
Return type
Errhandler
static __new__(cls, errhandler=None)
Parameters
errhandler (Optional[Errhandler]) –
Return type
Errhandler
Methods Summary
┌──────────┬───────────────────────┐
│Free() │ Free an error handler │
├──────────┼───────────────────────┤
│f2py(arg) │ │
├──────────┼───────────────────────┤
│py2f() │ │
└──────────┴───────────────────────┘
Methods Documentation
Free() Free an error handler
Return type
None
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Errhandler
py2f()
Return type
int
mpi4py.MPI.File
class mpi4py.MPI.File(file=None)
Bases: object
File handle
Parameters
file (Optional[File]) –
Return type
File
static __new__(cls, file=None)
Parameters
file (Optional[File]) –
Return type
File
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Call_errhandler(errorcode) │ Call the error handler in- │
│ │ stalled on a file │
├───────────────────────────┼────────────────────────────┤
│Close() │ Close a file │
├───────────────────────────┼────────────────────────────┤
│Delete(filename[, info]) │ Delete a file │
├───────────────────────────┼────────────────────────────┤
│Get_amode() │ Return the file access │
│ │ mode │
├───────────────────────────┼────────────────────────────┤
│Get_atomicity() │ Return the atomicity mode │
├───────────────────────────┼────────────────────────────┤
│Get_byte_offset(offset) │ Return the absolute byte │
│ │ position in the file cor- │
│ │ responding to 'offset' │
│ │ etypes relative to the │
│ │ current view │
├───────────────────────────┼────────────────────────────┤
│Get_errhandler() │ Get the error handler for │
│ │ a file │
├───────────────────────────┼────────────────────────────┤
│Get_group() │ Return the group of pro- │
│ │ cesses that opened the │
│ │ file │
├───────────────────────────┼────────────────────────────┤
│Get_info() │ Return the hints for a │
│ │ file that that are cur- │
│ │ rently in use │
├───────────────────────────┼────────────────────────────┤
│Get_position() │ Return the current posi- │
│ │ tion of the individual │
│ │ file pointer in etype │
│ │ units relative to the cur- │
│ │ rent view │
├───────────────────────────┼────────────────────────────┤
│Get_position_shared() │ Return the current posi- │
│ │ tion of the shared file │
│ │ pointer in etype units │
│ │ relative to the current │
│ │ view │
├───────────────────────────┼────────────────────────────┤
│Get_size() │ Return the file size │
├───────────────────────────┼────────────────────────────┤
│Get_type_extent(datatype) │ Return the extent of │
│ │ datatype in the file │
├───────────────────────────┼────────────────────────────┤
│Get_view() │ Return the file view │
├───────────────────────────┼────────────────────────────┤
│Iread(buf) │ Nonblocking read using in- │
│ │ dividual file pointer │
├───────────────────────────┼────────────────────────────┤
│Iread_all(buf) │ Nonblocking collective │
│ │ read using individual file │
│ │ pointer │
├───────────────────────────┼────────────────────────────┤
│Iread_at(offset, buf) │ Nonblocking read using ex- │
│ │ plicit offset │
├───────────────────────────┼────────────────────────────┤
│Iread_at_all(offset, buf) │ Nonblocking collective │
│ │ read using explicit offset │
├───────────────────────────┼────────────────────────────┤
│Iread_shared(buf) │ Nonblocking read using │
│ │ shared file pointer │
├───────────────────────────┼────────────────────────────┤
│Iwrite(buf) │ Nonblocking write using │
│ │ individual file pointer │
├───────────────────────────┼────────────────────────────┤
│Iwrite_all(buf) │ Nonblocking collective │
│ │ write using individual │
│ │ file pointer │
├───────────────────────────┼────────────────────────────┤
│Iwrite_at(offset, buf) │ Nonblocking write using │
│ │ explicit offset │
├───────────────────────────┼────────────────────────────┤
│Iwrite_at_all(offset, buf) │ Nonblocking collective │
│ │ write using explicit off- │
│ │ set │
├───────────────────────────┼────────────────────────────┤
│Iwrite_shared(buf) │ Nonblocking write using │
│ │ shared file pointer │
└───────────────────────────┴────────────────────────────┘
│Open(comm, filename[, │ Open a file │
│amode, info]) │ │
├───────────────────────────┼────────────────────────────┤
│Preallocate(size) │ Preallocate storage space │
│ │ for a file │
├───────────────────────────┼────────────────────────────┤
│Read(buf[, status]) │ Read using individual file │
│ │ pointer │
├───────────────────────────┼────────────────────────────┤
│Read_all(buf[, status]) │ Collective read using in- │
│ │ dividual file pointer │
├───────────────────────────┼────────────────────────────┤
│Read_all_begin(buf) │ Start a split collective │
│ │ read using individual file │
│ │ pointer │
├───────────────────────────┼────────────────────────────┤
│Read_all_end(buf[, sta- │ Complete a split collec- │
│tus]) │ tive read using individual │
│ │ file pointer │
├───────────────────────────┼────────────────────────────┤
│Read_at(offset, buf[, sta- │ Read using explicit offset │
│tus]) │ │
├───────────────────────────┼────────────────────────────┤
│Read_at_all(offset, buf[, │ Collective read using ex- │
│status]) │ plicit offset │
├───────────────────────────┼────────────────────────────┤
│Read_at_all_begin(offset, │ Start a split collective │
│buf) │ read using explict offset │
├───────────────────────────┼────────────────────────────┤
│Read_at_all_end(buf[, sta- │ Complete a split collec- │
│tus]) │ tive read using explict │
│ │ offset │
├───────────────────────────┼────────────────────────────┤
│Read_ordered(buf[, sta- │ Collective read using │
│tus]) │ shared file pointer │
├───────────────────────────┼────────────────────────────┤
│Read_ordered_begin(buf) │ Start a split collective │
│ │ read using shared file │
│ │ pointer │
├───────────────────────────┼────────────────────────────┤
│Read_ordered_end(buf[, │ Complete a split collec- │
│status]) │ tive read using shared │
│ │ file pointer │
├───────────────────────────┼────────────────────────────┤
│Read_shared(buf[, status]) │ Read using shared file │
│ │ pointer │
├───────────────────────────┼────────────────────────────┤
│Seek(offset[, whence]) │ Update the individual file │
│ │ pointer │
├───────────────────────────┼────────────────────────────┤
│Seek_shared(offset[, │ Update the shared file │
│whence]) │ pointer │
├───────────────────────────┼────────────────────────────┤
│Set_atomicity(flag) │ Set the atomicity mode │
├───────────────────────────┼────────────────────────────┤
│Set_errhandler(errhandler) │ Set the error handler for │
│ │ a file │
├───────────────────────────┼────────────────────────────┤
│Set_info(info) │ Set new values for the │
│ │ hints associated with a │
│ │ file │
├───────────────────────────┼────────────────────────────┤
│Set_size(size) │ Sets the file size │
├───────────────────────────┼────────────────────────────┤
│Set_view([disp, etype, │ Set the file view │
│filetype, datarep, info]) │ │
├───────────────────────────┼────────────────────────────┤
│Sync() │ Causes all previous writes │
│ │ to be transferred to the │
│ │ storage device │
├───────────────────────────┼────────────────────────────┤
│Write(buf[, status]) │ Write using individual │
│ │ file pointer │
├───────────────────────────┼────────────────────────────┤
│Write_all(buf[, status]) │ Collective write using in- │
│ │ dividual file pointer │
├───────────────────────────┼────────────────────────────┤
│Write_all_begin(buf) │ Start a split collective │
│ │ write using individual │
│ │ file pointer │
├───────────────────────────┼────────────────────────────┤
│Write_all_end(buf[, sta- │ Complete a split collec- │
│tus]) │ tive write using individ- │
│ │ ual file pointer │
├───────────────────────────┼────────────────────────────┤
│Write_at(offset, buf[, │ Write using explicit off- │
│status]) │ set │
├───────────────────────────┼────────────────────────────┤
│Write_at_all(offset, buf[, │ Collective write using ex- │
│status]) │ plicit offset │
├───────────────────────────┼────────────────────────────┤
│Write_at_all_begin(offset, │ Start a split collective │
│buf) │ write using explict offset │
├───────────────────────────┼────────────────────────────┤
│Write_at_all_end(buf[, │ Complete a split collec- │
│status]) │ tive write using explict │
│ │ offset │
├───────────────────────────┼────────────────────────────┤
│Write_ordered(buf[, sta- │ Collective write using │
│tus]) │ shared file pointer │
├───────────────────────────┼────────────────────────────┤
│Write_ordered_begin(buf) │ Start a split collective │
│ │ write using shared file │
│ │ pointer │
└───────────────────────────┴────────────────────────────┘
│Write_ordered_end(buf[, │ Complete a split collec- │
│status]) │ tive write using shared │
│ │ file pointer │
├───────────────────────────┼────────────────────────────┤
│Write_shared(buf[, sta- │ Write using shared file │
│tus]) │ pointer │
├───────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────┼────────────────────────────┤
│py2f() │ │
└───────────────────────────┴────────────────────────────┘
Attributes Summary
┌──────────┬──────────────────┐
│amode │ file access mode │
├──────────┼──────────────────┤
│atomicity │ │
├──────────┼──────────────────┤
│group │ file group │
├──────────┼──────────────────┤
│info │ file info │
├──────────┼──────────────────┤
│size │ file size │
└──────────┴──────────────────┘
Methods Documentation
Call_errhandler(errorcode)
Call the error handler installed on a file
Parameters
errorcode (int) –
Return type
None
Close()
Close a file
Return type
None
classmethod Delete(filename, info=INFO_NULL)
Delete a file
Parameters
• filename (str) –
• info (Info) –
Return type
None
Get_amode()
Return the file access mode
Return type
int
Get_atomicity()
Return the atomicity mode
Return type
bool
Get_byte_offset(offset)
Return the absolute byte position in the file correspond-
ing to ‘offset’ etypes relative to the current view
Parameters
offset (int) –
Return type
int
Get_errhandler()
Get the error handler for a file
Return type
Errhandler
Get_group()
Return the group of processes that opened the file
Return type
Group
Get_info()
Return the hints for a file that that are currently in
use
Return type
Info
Get_position()
Return the current position of the individual file
pointer in etype units relative to the current view
Return type
int
Get_position_shared()
Return the current position of the shared file pointer in
etype units relative to the current view
Return type
int
Get_size()
Return the file size
Return type
int
Get_type_extent(datatype)
Return the extent of datatype in the file
Parameters
datatype (Datatype) –
Return type
int
Get_view()
Return the file view
Return type
Tuple[int, Datatype, Datatype, str]
Iread(buf)
Nonblocking read using individual file pointer
Parameters
buf (BufSpec) –
Return type
Request
Iread_all(buf)
Nonblocking collective read using individual file pointer
Parameters
buf (BufSpec) –
Return type
Request
Iread_at(offset, buf)
Nonblocking read using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
Return type
Request
Iread_at_all(offset, buf)
Nonblocking collective read using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
Return type
Request
Iread_shared(buf)
Nonblocking read using shared file pointer
Parameters
buf (BufSpec) –
Return type
Request
Iwrite(buf)
Nonblocking write using individual file pointer
Parameters
buf (BufSpec) –
Return type
Request
Iwrite_all(buf)
Nonblocking collective write using individual file
pointer
Parameters
buf (BufSpec) –
Return type
Request
Iwrite_at(offset, buf)
Nonblocking write using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
Return type
Request
Iwrite_at_all(offset, buf)
Nonblocking collective write using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
Return type
Request
Iwrite_shared(buf)
Nonblocking write using shared file pointer
Parameters
buf (BufSpec) –
Return type
Request
classmethod Open(comm, filename, amode=MODE_RDONLY,
info=INFO_NULL)
Open a file
Parameters
• comm (Intracomm) –
• filename (str) –
• amode (int) –
• info (Info) –
Return type
File
Preallocate(size)
Preallocate storage space for a file
Parameters
size (int) –
Return type
None
Read(buf, status=None)
Read using individual file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_all(buf, status=None)
Collective read using individual file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_all_begin(buf)
Start a split collective read using individual file
pointer
Parameters
buf (BufSpec) –
Return type
None
Read_all_end(buf, status=None)
Complete a split collective read using individual file
pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_at(offset, buf, status=None)
Read using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_at_all(offset, buf, status=None)
Collective read using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_at_all_begin(offset, buf)
Start a split collective read using explict offset
Parameters
• offset (int) –
• buf (BufSpec) –
Return type
None
Read_at_all_end(buf, status=None)
Complete a split collective read using explict offset
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_ordered(buf, status=None)
Collective read using shared file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_ordered_begin(buf)
Start a split collective read using shared file pointer
Parameters
buf (BufSpec) –
Return type
None
Read_ordered_end(buf, status=None)
Complete a split collective read using shared file
pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Read_shared(buf, status=None)
Read using shared file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Seek(offset, whence=SEEK_SET)
Update the individual file pointer
Parameters
• offset (int) –
• whence (int) –
Return type
None
Seek_shared(offset, whence=SEEK_SET)
Update the shared file pointer
Parameters
• offset (int) –
• whence (int) –
Return type
None
Set_atomicity(flag)
Set the atomicity mode
Parameters
flag (bool) –
Return type
None
Set_errhandler(errhandler)
Set the error handler for a file
Parameters
errhandler (Errhandler) –
Return type
None
Set_info(info)
Set new values for the hints associated with a file
Parameters
info (Info) –
Return type
None
Set_size(size)
Sets the file size
Parameters
size (int) –
Return type
None
Set_view(disp=0, etype=BYTE, filetype=None, datarep='native',
info=INFO_NULL)
Set the file view
Parameters
• disp (int) –
• etype (Datatype) –
• filetype (Optional[Datatype]) –
• datarep (str) –
• info (Info) –
Return type
None
Sync() Causes all previous writes to be transferred to the stor-
age device
Return type
None
Write(buf, status=None)
Write using individual file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_all(buf, status=None)
Collective write using individual file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_all_begin(buf)
Start a split collective write using individual file
pointer
Parameters
buf (BufSpec) –
Return type
None
Write_all_end(buf, status=None)
Complete a split collective write using individual file
pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_at(offset, buf, status=None)
Write using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_at_all(offset, buf, status=None)
Collective write using explicit offset
Parameters
• offset (int) –
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_at_all_begin(offset, buf)
Start a split collective write using explict offset
Parameters
• offset (int) –
• buf (BufSpec) –
Return type
None
Write_at_all_end(buf, status=None)
Complete a split collective write using explict offset
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_ordered(buf, status=None)
Collective write using shared file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_ordered_begin(buf)
Start a split collective write using shared file pointer
Parameters
buf (BufSpec) –
Return type
None
Write_ordered_end(buf, status=None)
Complete a split collective write using shared file
pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
Write_shared(buf, status=None)
Write using shared file pointer
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
classmethod f2py(arg)
Parameters
arg (int) –
Return type
File
py2f()
Return type
int
Attributes Documentation
amode file access mode
atomicity
group file group
info file info
size file size
mpi4py.MPI.Graphcomm
class mpi4py.MPI.Graphcomm(comm=None)
Bases: mpi4py.MPI.Topocomm
General graph topology intracommunicator
Parameters
comm (Optional[Graphcomm]) –
Return type
Graphcomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Graphcomm]) –
Return type
Graphcomm
Methods Summary
┌──────────────────────────┬────────────────────────────┐
│Get_dims() │ Return the number of nodes │
│ │ and edges │
├──────────────────────────┼────────────────────────────┤
│Get_neighbors(rank) │ Return list of neighbors │
│ │ of a process │
├──────────────────────────┼────────────────────────────┤
│Get_neighbors_count(rank) │ Return number of neighbors │
│ │ of a process │
├──────────────────────────┼────────────────────────────┤
│Get_topo() │ Return index and edges │
└──────────────────────────┴────────────────────────────┘
Attributes Summary
┌───────────┬───────────────────────────┐
│dims │ number of nodes and edges │
├───────────┼───────────────────────────┤
│edges │ │
├───────────┼───────────────────────────┤
│index │ │
├───────────┼───────────────────────────┤
│nedges │ number of edges │
├───────────┼───────────────────────────┤
│neighbors │ │
├───────────┼───────────────────────────┤
│nneighbors │ number of neighbors │
├───────────┼───────────────────────────┤
│nnodes │ number of nodes │
├───────────┼───────────────────────────┤
│topo │ topology information │
└───────────┴───────────────────────────┘
Methods Documentation
Get_dims()
Return the number of nodes and edges
Return type
Tuple[int, int]
Get_neighbors(rank)
Return list of neighbors of a process
Parameters
rank (int) –
Return type
List[int]
Get_neighbors_count(rank)
Return number of neighbors of a process
Parameters
rank (int) –
Return type
int
Get_topo()
Return index and edges
Return type
Tuple[List[int], List[int]]
Attributes Documentation
dims number of nodes and edges
edges
index
nedges number of edges
neighbors
nneighbors
number of neighbors
nnodes number of nodes
topo topology information
mpi4py.MPI.Grequest
class mpi4py.MPI.Grequest(request=None)
Bases: mpi4py.MPI.Request
Generalized request handle
Parameters
request (Optional[Grequest]) –
Return type
Grequest
static __new__(cls, request=None)
Parameters
request (Optional[Grequest]) –
Return type
Grequest
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Complete() │ Notify that a user-defined │
│ │ request is complete │
├───────────────────────────┼────────────────────────────┤
│Start(query_fn, free_fn, │ Create and return a │
│cancel_fn[, args, ...]) │ user-defined request │
└───────────────────────────┴────────────────────────────┘
Methods Documentation
Complete()
Notify that a user-defined request is complete
Return type
None
classmethod Start(query_fn, free_fn, cancel_fn, args=None,
kargs=None)
Create and return a user-defined request
Parameters
• query_fn (Callable[..., None]) –
• free_fn (Callable[..., None]) –
• cancel_fn (Callable[..., None]) –
• args (Optional[Tuple[Any]]) –
• kargs (Optional[Dict[str, Any]]) –
Return type
Grequest
mpi4py.MPI.Group
class mpi4py.MPI.Group(group=None)
Bases: object
Group of processes
Parameters
group (Optional[Group]) –
Return type
Group
static __new__(cls, group=None)
Parameters
group (Optional[Group]) –
Return type
Group
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Compare(group1, group2) │ Compare two groups │
├───────────────────────────┼────────────────────────────┤
│Difference(group1, group2) │ Produce a group from the │
│ │ difference of two existing │
│ │ groups │
├───────────────────────────┼────────────────────────────┤
│Dup() │ Duplicate a group │
├───────────────────────────┼────────────────────────────┤
│Excl(ranks) │ Produce a group by re- │
│ │ ordering an existing group │
│ │ and taking only unlisted │
│ │ members │
├───────────────────────────┼────────────────────────────┤
│Free() │ Free a group │
├───────────────────────────┼────────────────────────────┤
│Get_rank() │ Return the rank of this │
│ │ process in a group │
├───────────────────────────┼────────────────────────────┤
│Get_size() │ Return the size of a group │
├───────────────────────────┼────────────────────────────┤
│Incl(ranks) │ Produce a group by re- │
│ │ ordering an existing group │
│ │ and taking only listed │
│ │ members │
├───────────────────────────┼────────────────────────────┤
│Intersection(group1, │ Produce a group as the in- │
│group2) │ tersection of two existing │
│ │ groups │
├───────────────────────────┼────────────────────────────┤
│Range_excl(ranks) │ Create a new group by ex- │
│ │ cluding ranges of pro- │
│ │ cesses from an existing │
│ │ group │
├───────────────────────────┼────────────────────────────┤
│Range_incl(ranks) │ Create a new group from │
│ │ ranges of of ranks in an │
│ │ existing group │
├───────────────────────────┼────────────────────────────┤
│Translate_ranks(group1, │ Translate the ranks of │
│ranks1[, group2]) │ processes in one group to │
│ │ those in another group │
├───────────────────────────┼────────────────────────────┤
│Union(group1, group2) │ Produce a group by combin- │
│ │ ing two existing groups │
├───────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────┼────────────────────────────┤
│py2f() │ │
└───────────────────────────┴────────────────────────────┘
Attributes Summary
┌─────┬────────────────────────────┐
│rank │ rank of this process in │
│ │ group │
└─────┴────────────────────────────┘
│size │ number of processes in │
│ │ group │
└─────┴────────────────────────────┘
Methods Documentation
classmethod Compare(group1, group2)
Compare two groups
Parameters
• group1 (Group) –
• group2 (Group) –
Return type
int
classmethod Difference(group1, group2)
Produce a group from the difference of two existing
groups
Parameters
• group1 (Group) –
• group2 (Group) –
Return type
Group
Dup() Duplicate a group
Return type
Group
Excl(ranks)
Produce a group by reordering an existing group and tak-
ing only unlisted members
Parameters
ranks (Sequence[int]) –
Return type
Group
Free() Free a group
Return type
None
Get_rank()
Return the rank of this process in a group
Return type
int
Get_size()
Return the size of a group
Return type
int
Incl(ranks)
Produce a group by reordering an existing group and tak-
ing only listed members
Parameters
ranks (Sequence[int]) –
Return type
Group
classmethod Intersection(group1, group2)
Produce a group as the intersection of two existing
groups
Parameters
• group1 (Group) –
• group2 (Group) –
Return type
Group
Range_excl(ranks)
Create a new group by excluding ranges of processes from
an existing group
Parameters
ranks (Sequence[Tuple[int, int, int]]) –
Return type
Group
Range_incl(ranks)
Create a new group from ranges of of ranks in an existing
group
Parameters
ranks (Sequence[Tuple[int, int, int]]) –
Return type
Group
classmethod Translate_ranks(group1, ranks1, group2=None)
Translate the ranks of processes in one group to those in
another group
Parameters
• group1 (Group) –
• ranks1 (Sequence[int]) –
• group2 (Optional[Group]) –
Return type
List[int]
classmethod Union(group1, group2)
Produce a group by combining two existing groups
Parameters
• group1 (Group) –
• group2 (Group) –
Return type
Group
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Group
py2f()
Return type
int
Attributes Documentation
rank rank of this process in group
size number of processes in group
mpi4py.MPI.Info
class mpi4py.MPI.Info(info=None)
Bases: object
Info object
Parameters
info (Optional[Info]) –
Return type
Info
static __new__(cls, info=None)
Parameters
info (Optional[Info]) –
Return type
Info
Methods Summary
┌────────────────────┬────────────────────────────┐
│Create() │ Create a new, empty info │
│ │ object │
├────────────────────┼────────────────────────────┤
│Delete(key) │ Remove a (key, value) pair │
│ │ from info │
├────────────────────┼────────────────────────────┤
│Dup() │ Duplicate an existing info │
│ │ object, creating a new ob- │
│ │ ject, with the same (key, │
│ │ value) pairs and the same │
│ │ ordering of keys │
├────────────────────┼────────────────────────────┤
│Free() │ Free a info object │
├────────────────────┼────────────────────────────┤
│Get(key[, maxlen]) │ Retrieve the value associ- │
│ │ ated with a key │
├────────────────────┼────────────────────────────┤
│Get_nkeys() │ Return the number of cur- │
│ │ rently defined keys in │
│ │ info │
├────────────────────┼────────────────────────────┤
│Get_nthkey(n) │ Return the nth defined key │
│ │ in info. │
├────────────────────┼────────────────────────────┤
│Set(key, value) │ Add the (key, value) pair │
│ │ to info, and overrides the │
│ │ value if a value for the │
│ │ same key was previously │
│ │ set │
├────────────────────┼────────────────────────────┤
│clear() │ info clear │
├────────────────────┼────────────────────────────┤
│copy() │ info copy │
├────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├────────────────────┼────────────────────────────┤
│get(key[, default]) │ info get │
├────────────────────┼────────────────────────────┤
│items() │ info items │
├────────────────────┼────────────────────────────┤
│keys() │ info keys │
├────────────────────┼────────────────────────────┤
│pop(key, *default) │ info pop │
├────────────────────┼────────────────────────────┤
│popitem() │ info popitem │
├────────────────────┼────────────────────────────┤
│py2f() │ │
├────────────────────┼────────────────────────────┤
│update([other]) │ info update │
├────────────────────┼────────────────────────────┤
│values() │ info values │
└────────────────────┴────────────────────────────┘
Methods Documentation
classmethod Create()
Create a new, empty info object
Return type
Info
Delete(key)
Remove a (key, value) pair from info
Parameters
key (str) –
Return type
None
Dup() Duplicate an existing info object, creating a new object,
with the same (key, value) pairs and the same ordering of
keys
Return type
Info
Free() Free a info object
Return type
None
Get(key, maxlen=- 1)
Retrieve the value associated with a key
Parameters
• key (str) –
• maxlen (int) –
Return type
Optional[str]
Get_nkeys()
Return the number of currently defined keys in info
Return type
int
Get_nthkey(n)
Return the nth defined key in info. Keys are numbered in
the range [0, N) where N is the value returned by
Info.Get_nkeys()
Parameters
n (int) –
Return type
str
Set(key, value)
Add the (key, value) pair to info, and overrides the
value if a value for the same key was previously set
Parameters
• key (str) –
• value (str) –
Return type
None
clear()
info clear
Return type
None
copy() info copy
Return type
Info
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Info
get(key, default=None)
info get
Parameters
• key (str) –
• default (Optional[str]) –
Return type
Optional[str]
items()
info items
Return type
List[Tuple[str, str]]
keys() info keys
Return type
List[str]
pop(key, *default)
info pop
Parameters
• key (str) –
• default (str) –
Return type
str
popitem()
info popitem
Return type
Tuple[str, str]
py2f()
Return type
int
update(other=(), **kwds)
info update
Parameters
• other (Union[Info, Mapping[str, str], Iter-
able[Tuple[str, str]]]) –
• kwds (str) –
Return type
None
values()
info values
Return type
List[str]
mpi4py.MPI.Intercomm
class mpi4py.MPI.Intercomm(comm=None)
Bases: mpi4py.MPI.Comm
Intercommunicator
Parameters
comm (Optional[Intercomm]) –
Return type
Intercomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Intercomm]) –
Return type
Intercomm
Methods Summary
┌───────────────────┬────────────────────────────┐
│Get_remote_group() │ Access the remote group │
│ │ associated with the in- │
│ │ ter-communicator │
├───────────────────┼────────────────────────────┤
│Get_remote_size() │ Intercommunicator remote │
│ │ size │
├───────────────────┼────────────────────────────┤
│Merge([high]) │ Merge intercommunicator │
└───────────────────┴────────────────────────────┘
Attributes Summary
┌─────────────┬────────────────────────────┐
│remote_group │ remote group │
├─────────────┼────────────────────────────┤
│remote_size │ number of remote processes │
└─────────────┴────────────────────────────┘
Methods Documentation
Get_remote_group()
Access the remote group associated with the inter-commu-
nicator
Return type
Group
Get_remote_size()
Intercommunicator remote size
Return type
int
Merge(high=False)
Merge intercommunicator
Parameters
high (bool) –
Return type
Intracomm
Attributes Documentation
remote_group
remote group
remote_size
number of remote processes
mpi4py.MPI.Intracomm
class mpi4py.MPI.Intracomm(comm=None)
Bases: mpi4py.MPI.Comm
Intracommunicator
Parameters
comm (Optional[Intracomm]) –
Return type
Intracomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Intracomm]) –
Return type
Intracomm
Methods Summary
┌────────────────────────────────────┬────────────────────────────┐
│Accept(port_name[, info, │ Accept a request to form a │
│root]) │ new intercommunicator │
├────────────────────────────────────┼────────────────────────────┤
│Cart_map(dims[, periods]) │ Return an optimal place- │
│ │ ment for the calling │
│ │ process on the physical │
│ │ machine │
├────────────────────────────────────┼────────────────────────────┤
│Connect(port_name[, info, │ Make a request to form a │
│root]) │ new intercommunicator │
├────────────────────────────────────┼────────────────────────────┤
│Create_cart(dims[, peri- │ Create cartesian communi- │
│ods, reorder]) │ cator │
├────────────────────────────────────┼────────────────────────────┤
│Create_dist_graph(sources, │ Create distributed graph │
│degrees, destinations) │ communicator │
├────────────────────────────────────┼────────────────────────────┤
│Create_dist_graph_adjacent(sources, │ Create distributed graph │
│destinations) │ communicator │
├────────────────────────────────────┼────────────────────────────┤
│Create_graph(index, edges[, re- │ Create graph communicator │
│order]) │ │
├────────────────────────────────────┼────────────────────────────┤
│Create_intercomm(local_leader, │ Create intercommunicator │
│peer_comm, ...) │ │
├────────────────────────────────────┼────────────────────────────┤
│Exscan(sendbuf, recvbuf[, op]) │ Exclusive Scan │
├────────────────────────────────────┼────────────────────────────┤
│Graph_map(index, edges) │ Return an optimal place- │
│ │ ment for the calling │
│ │ process on the physical │
│ │ machine │
├────────────────────────────────────┼────────────────────────────┤
│Iexscan(sendbuf, recvbuf[, op]) │ Inclusive Scan │
├────────────────────────────────────┼────────────────────────────┤
│Iscan(sendbuf, recvbuf[, op]) │ Inclusive Scan │
├────────────────────────────────────┼────────────────────────────┤
│Scan(sendbuf, recvbuf[, op]) │ Inclusive Scan │
├────────────────────────────────────┼────────────────────────────┤
│Spawn(command[, args, maxprocs, │ Spawn instances of a sin- │
│info, root, ...]) │ gle MPI application │
├────────────────────────────────────┼────────────────────────────┤
│Spawn_multiple(command[, args, max- │ Spawn instances of multi- │
│procs, ...]) │ ple MPI applications │
├────────────────────────────────────┼────────────────────────────┤
│exscan(sendobj[, op]) │ Exclusive Scan │
├────────────────────────────────────┼────────────────────────────┤
│scan(sendobj[, op]) │ Inclusive Scan │
└────────────────────────────────────┴────────────────────────────┘
Methods Documentation
Accept(port_name, info=INFO_NULL, root=0)
Accept a request to form a new intercommunicator
Parameters
• port_name (str) –
• info (Info) –
• root (int) –
Return type
Intercomm
Cart_map(dims, periods=None)
Return an optimal placement for the calling process on
the physical machine
Parameters
• dims (Sequence[int]) –
• periods (Optional[Sequence[bool]]) –
Return type
int
Connect(port_name, info=INFO_NULL, root=0)
Make a request to form a new intercommunicator
Parameters
• port_name (str) –
• info (Info) –
• root (int) –
Return type
Intercomm
Create_cart(dims, periods=None, reorder=False)
Create cartesian communicator
Parameters
• dims (Sequence[int]) –
• periods (Optional[Sequence[bool]]) –
• reorder (bool) –
Return type
Cartcomm
Create_dist_graph(sources, degrees, destinations, weights=None,
info=INFO_NULL, reorder=False)
Create distributed graph communicator
Parameters
• sources (Sequence[int]) –
• degrees (Sequence[int]) –
• destinations (Sequence[int]) –
• weights (Optional[Sequence[int]]) –
• info (Info) –
• reorder (bool) –
Return type
Distgraphcomm
Create_dist_graph_adjacent(sources, destinations,
sourceweights=None, destweights=None, info=INFO_NULL, re-
order=False)
Create distributed graph communicator
Parameters
• sources (Sequence[int]) –
• destinations (Sequence[int]) –
• sourceweights (Optional[Sequence[int]]) –
• destweights (Optional[Sequence[int]]) –
• info (Info) –
• reorder (bool) –
Return type
Distgraphcomm
Create_graph(index, edges, reorder=False)
Create graph communicator
Parameters
• index (Sequence[int]) –
• edges (Sequence[int]) –
• reorder (bool) –
Return type
Graphcomm
Create_intercomm(local_leader, peer_comm, remote_leader, tag=0)
Create intercommunicator
Parameters
• local_leader (int) –
• peer_comm (Intracomm) –
• remote_leader (int) –
• tag (int) –
Return type
Intercomm
Exscan(sendbuf, recvbuf, op=SUM)
Exclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• op (Op) –
Return type
None
Graph_map(index, edges)
Return an optimal placement for the calling process on
the physical machine
Parameters
• index (Sequence[int]) –
• edges (Sequence[int]) –
Return type
int
Iexscan(sendbuf, recvbuf, op=SUM)
Inclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• op (Op) –
Return type
Request
Iscan(sendbuf, recvbuf, op=SUM)
Inclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• op (Op) –
Return type
Request
Scan(sendbuf, recvbuf, op=SUM)
Inclusive Scan
Parameters
• sendbuf (Union[BufSpec, InPlace]) –
• recvbuf (BufSpec) –
• op (Op) –
Return type
None
Spawn(command, args=None, maxprocs=1, info=INFO_NULL, root=0,
errcodes=None)
Spawn instances of a single MPI application
Parameters
• command (str) –
• args (Optional[Sequence[str]]) –
• maxprocs (int) –
• info (Info) –
• root (int) –
• errcodes (Optional[list]) –
Return type
Intercomm
Spawn_multiple(command, args=None, maxprocs=None,
info=INFO_NULL, root=0, errcodes=None)
Spawn instances of multiple MPI applications
Parameters
• command (Sequence[str]) –
• args (Optional[Sequence[Sequence[str]]]) –
• maxprocs (Optional[Sequence[int]]) –
• info (Union[Info, Sequence[Info]]) –
• root (int) –
• errcodes (Optional[list]) –
Return type
Intercomm
exscan(sendobj, op=SUM)
Exclusive Scan
Parameters
• sendobj (Any) –
• op (Union[Op, Callable[[Any, Any], Any]]) –
Return type
Any
scan(sendobj, op=SUM)
Inclusive Scan
Parameters
• sendobj (Any) –
• op (Union[Op, Callable[[Any, Any], Any]]) –
Return type
Any
mpi4py.MPI.Message
class mpi4py.MPI.Message(message=None)
Bases: object
Matched message handle
Parameters
message (Optional[Message]) –
Return type
Message
static __new__(cls, message=None)
Parameters
message (Optional[Message]) –
Return type
Message
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Iprobe(comm[, source, tag, │ Nonblocking test for a │
│status]) │ matched message │
├───────────────────────────┼────────────────────────────┤
│Irecv(buf) │ Nonblocking receive of │
│ │ matched message │
├───────────────────────────┼────────────────────────────┤
│Probe(comm[, source, tag, │ Blocking test for a │
│status]) │ matched message │
├───────────────────────────┼────────────────────────────┤
│Recv(buf[, status]) │ Blocking receive of │
│ │ matched message │
├───────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────┼────────────────────────────┤
│iprobe(comm[, source, tag, │ Nonblocking test for a │
│status]) │ matched message │
├───────────────────────────┼────────────────────────────┤
│irecv() │ Nonblocking receive of │
│ │ matched message │
└───────────────────────────┴────────────────────────────┘
│probe(comm[, source, tag, │ Blocking test for a │
│status]) │ matched message │
├───────────────────────────┼────────────────────────────┤
│py2f() │ │
├───────────────────────────┼────────────────────────────┤
│recv([status]) │ Blocking receive of │
│ │ matched message │
└───────────────────────────┴────────────────────────────┘
Methods Documentation
classmethod Iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, sta-
tus=None)
Nonblocking test for a matched message
Parameters
• comm (Comm) –
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Optional[Message]
Irecv(buf)
Nonblocking receive of matched message
Parameters
buf (BufSpec) –
Return type
Request
classmethod Probe(comm, source=ANY_SOURCE, tag=ANY_TAG, sta-
tus=None)
Blocking test for a matched message
Parameters
• comm (Comm) –
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Message
Recv(buf, status=None)
Blocking receive of matched message
Parameters
• buf (BufSpec) –
• status (Optional[Status]) –
Return type
None
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Message
classmethod iprobe(comm, source=ANY_SOURCE, tag=ANY_TAG, sta-
tus=None)
Nonblocking test for a matched message
Parameters
• comm (Comm) –
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Optional[Message]
irecv()
Nonblocking receive of matched message
Return type
Request
classmethod probe(comm, source=ANY_SOURCE, tag=ANY_TAG, sta-
tus=None)
Blocking test for a matched message
Parameters
• comm (Comm) –
• source (int) –
• tag (int) –
• status (Optional[Status]) –
Return type
Message
py2f()
Return type
int
recv(status=None)
Blocking receive of matched message
Parameters
status (Optional[Status]) –
Return type
Any
mpi4py.MPI.Op
class mpi4py.MPI.Op(op=None)
Bases: object
Operation object
Parameters
op (Optional[Op]) –
Return type
Op
static __new__(cls, op=None)
Parameters
op (Optional[Op]) –
Return type
Op
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Create(function[, com- │ Create a user-defined op- │
│mute]) │ eration │
├───────────────────────────┼────────────────────────────┤
│Free() │ Free the operation │
├───────────────────────────┼────────────────────────────┤
│Is_commutative() │ Query reduction operations │
│ │ for their commutativity │
├───────────────────────────┼────────────────────────────┤
│Reduce_local(inbuf, inout- │ Apply a reduction operator │
│buf) │ to local data │
├───────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────┼────────────────────────────┤
│py2f() │ │
└───────────────────────────┴────────────────────────────┘
Attributes Summary
┌───────────────┬───────────────────────────┐
│is_commutative │ is commutative │
├───────────────┼───────────────────────────┤
│is_predefined │ is a predefined operation │
└───────────────┴───────────────────────────┘
Methods Documentation
classmethod Create(function, commute=False)
Create a user-defined operation
Parameters
• function (Callable[[Buffer, Buffer, Datatype],
None]) –
• commute (bool) –
Return type
Op
Free() Free the operation
Return type
None
Is_commutative()
Query reduction operations for their commutativity
Return type
bool
Reduce_local(inbuf, inoutbuf)
Apply a reduction operator to local data
Parameters
• inbuf (BufSpec) –
• inoutbuf (BufSpec) –
Return type
None
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Op
py2f()
Return type
int
Attributes Documentation
is_commutative
is commutative
is_predefined
is a predefined operation
mpi4py.MPI.Pickle
class mpi4py.MPI.Pickle(dumps=None, loads=None, protocol=None)
Bases: object
Pickle/unpickle Python objects
Parameters
• dumps (Optional[Callable[[Any, int], bytes]]) –
• loads (Optional[Callable[[Buffer], Any]]) –
• protocol (Optional[int]) –
Return type
None
__init__(dumps=None, loads=None, protocol=None)
Parameters
• dumps (Optional[Callable[[Any, int], bytes]]) –
• loads (Optional[Callable[[Buffer], Any]]) –
• protocol (Optional[int]) –
Return type
None
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│dumps(obj[, buffer_call- │ Serialize object to pickle │
│back]) │ data stream. │
├───────────────────────────┼────────────────────────────┤
│loads(data[, buffers]) │ Deserialize object from │
│ │ pickle data stream. │
└───────────────────────────┴────────────────────────────┘
Attributes Summary
┌─────────┬─────────────────┐
│PROTOCOL │ pickle protocol │
└─────────┴─────────────────┘
Methods Documentation
dumps(obj, buffer_callback=None)
Serialize object to pickle data stream.
Parameters
• obj (Any) –
• buffer_callback (Optional[Callable[[Buffer],
Any]]) –
Return type
bytes
loads(data, buffers=None)
Deserialize object from pickle data stream.
Parameters
• data (Buffer) –
• buffers (Optional[Iterable[Buffer]]) –
Return type
Any
Attributes Documentation
PROTOCOL
pickle protocol
mpi4py.MPI.Prequest
class mpi4py.MPI.Prequest(request=None)
Bases: mpi4py.MPI.Request
Persistent request handle
Parameters
request (Optional[Prequest]) –
Return type
Prequest
static __new__(cls, request=None)
Parameters
request (Optional[Prequest]) –
Return type
Prequest
Methods Summary
┌───────────────────┬────────────────────────────┐
│Start() │ Initiate a communication │
│ │ with a persistent request │
├───────────────────┼────────────────────────────┤
│Startall(requests) │ Start a collection of per- │
│ │ sistent requests │
└───────────────────┴────────────────────────────┘
Methods Documentation
Start()
Initiate a communication with a persistent request
Return type
None
classmethod Startall(requests)
Start a collection of persistent requests
Parameters
requests (List[Prequest]) –
Return type
None
mpi4py.MPI.Request
class mpi4py.MPI.Request(request=None)
Bases: object
Request handle
Parameters
request (Optional[Request]) –
Return type
Request
static __new__(cls, request=None)
Parameters
request (Optional[Request]) –
Return type
Request
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Cancel() │ Cancel a communication re- │
│ │ quest │
├───────────────────────────┼────────────────────────────┤
│Free() │ Free a communication re- │
│ │ quest │
├───────────────────────────┼────────────────────────────┤
│Get_status([status]) │ Non-destructive test for │
│ │ the completion of a re- │
│ │ quest │
├───────────────────────────┼────────────────────────────┤
│Test([status]) │ Test for the completion of │
│ │ a send or receive │
├───────────────────────────┼────────────────────────────┤
│Testall(requests[, sta- │ Test for completion of all │
│tuses]) │ previously initiated re- │
│ │ quests │
├───────────────────────────┼────────────────────────────┤
│Testany(requests[, sta- │ Test for completion of any │
│tus]) │ previously initiated re- │
│ │ quest │
├───────────────────────────┼────────────────────────────┤
│Testsome(requests[, sta- │ Test for completion of │
│tuses]) │ some previously initiated │
│ │ requests │
├───────────────────────────┼────────────────────────────┤
│Wait([status]) │ Wait for a send or receive │
│ │ to complete │
├───────────────────────────┼────────────────────────────┤
│Waitall(requests[, sta- │ Wait for all previously │
│tuses]) │ initiated requests to com- │
│ │ plete │
├───────────────────────────┼────────────────────────────┤
│Waitany(requests[, sta- │ Wait for any previously │
│tus]) │ initiated request to com- │
│ │ plete │
├───────────────────────────┼────────────────────────────┤
│Waitsome(requests[, sta- │ Wait for some previously │
│tuses]) │ initiated requests to com- │
│ │ plete │
├───────────────────────────┼────────────────────────────┤
│cancel() │ Cancel a communication re- │
│ │ quest │
├───────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────┼────────────────────────────┤
│get_status([status]) │ Non-destructive test for │
│ │ the completion of a re- │
│ │ quest │
├───────────────────────────┼────────────────────────────┤
│py2f() │ │
├───────────────────────────┼────────────────────────────┤
│test([status]) │ Test for the completion of │
│ │ a send or receive │
├───────────────────────────┼────────────────────────────┤
│testall(requests[, sta- │ Test for completion of all │
│tuses]) │ previously initiated re- │
│ │ quests │
├───────────────────────────┼────────────────────────────┤
│testany(requests[, sta- │ Test for completion of any │
│tus]) │ previously initiated re- │
│ │ quest │
├───────────────────────────┼────────────────────────────┤
│testsome(requests[, sta- │ Test for completion of │
│tuses]) │ some previously initiated │
│ │ requests │
├───────────────────────────┼────────────────────────────┤
│wait([status]) │ Wait for a send or receive │
│ │ to complete │
├───────────────────────────┼────────────────────────────┤
│waitall(requests[, sta- │ Wait for all previously │
│tuses]) │ initiated requests to com- │
│ │ plete │
├───────────────────────────┼────────────────────────────┤
│waitany(requests[, sta- │ Wait for any previously │
│tus]) │ initiated request to com- │
│ │ plete │
├───────────────────────────┼────────────────────────────┤
│waitsome(requests[, sta- │ Wait for some previously │
│tuses]) │ initiated requests to com- │
│ │ plete │
└───────────────────────────┴────────────────────────────┘
Methods Documentation
Cancel()
Cancel a communication request
Return type
None
Free() Free a communication request
Return type
None
Get_status(status=None)
Non-destructive test for the completion of a request
Parameters
status (Optional[Status]) –
Return type
bool
Test(status=None)
Test for the completion of a send or receive
Parameters
status (Optional[Status]) –
Return type
bool
classmethod Testall(requests, statuses=None)
Test for completion of all previously initiated requests
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
bool
classmethod Testany(requests, status=None)
Test for completion of any previously initiated request
Parameters
• requests (Sequence[Request]) –
• status (Optional[Status]) –
Return type
Tuple[int, bool]
classmethod Testsome(requests, statuses=None)
Test for completion of some previously initiated requests
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
Optional[List[int]]
Wait(status=None)
Wait for a send or receive to complete
Parameters
status (Optional[Status]) –
Return type
Literal[True]
classmethod Waitall(requests, statuses=None)
Wait for all previously initiated requests to complete
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
Literal[True]
classmethod Waitany(requests, status=None)
Wait for any previously initiated request to complete
Parameters
• requests (Sequence[Request]) –
• status (Optional[Status]) –
Return type
int
classmethod Waitsome(requests, statuses=None)
Wait for some previously initiated requests to complete
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
Optional[List[int]]
cancel()
Cancel a communication request
Return type
None
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Request
get_status(status=None)
Non-destructive test for the completion of a request
Parameters
status (Optional[Status]) –
Return type
bool
py2f()
Return type
int
test(status=None)
Test for the completion of a send or receive
Parameters
status (Optional[Status]) –
Return type
Tuple[bool, Optional[Any]]
classmethod testall(requests, statuses=None)
Test for completion of all previously initiated requests
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
Tuple[bool, Optional[List[Any]]]
classmethod testany(requests, status=None)
Test for completion of any previously initiated request
Parameters
• requests (Sequence[Request]) –
• status (Optional[Status]) –
Return type
Tuple[int, bool, Optional[Any]]
classmethod testsome(requests, statuses=None)
Test for completion of some previously initiated requests
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
Tuple[Optional[List[int]], Optional[List[Any]]]
wait(status=None)
Wait for a send or receive to complete
Parameters
status (Optional[Status]) –
Return type
Any
classmethod waitall(requests, statuses=None)
Wait for all previously initiated requests to complete
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
List[Any]
classmethod waitany(requests, status=None)
Wait for any previously initiated request to complete
Parameters
• requests (Sequence[Request]) –
• status (Optional[Status]) –
Return type
Tuple[int, Any]
classmethod waitsome(requests, statuses=None)
Wait for some previously initiated requests to complete
Parameters
• requests (Sequence[Request]) –
• statuses (Optional[List[Status]]) –
Return type
Tuple[Optional[List[int]], Optional[List[Any]]]
mpi4py.MPI.Status
class mpi4py.MPI.Status(status=None)
Bases: object
Status object
Parameters
status (Optional[Status]) –
Return type
Status
static __new__(cls, status=None)
Parameters
status (Optional[Status]) –
Return type
Status
Methods Summary
┌───────────────────────┬────────────────────────────┐
│Get_count([datatype]) │ Get the number of top │
│ │ level elements │
├───────────────────────┼────────────────────────────┤
│Get_elements(datatype) │ Get the number of basic │
│ │ elements in a datatype │
├───────────────────────┼────────────────────────────┤
│Get_error() │ Get message error │
├───────────────────────┼────────────────────────────┤
│Get_source() │ Get message source │
├───────────────────────┼────────────────────────────┤
│Get_tag() │ Get message tag │
├───────────────────────┼────────────────────────────┤
│Is_cancelled() │ Test to see if a request │
│ │ was cancelled │
├───────────────────────┼────────────────────────────┤
│Set_cancelled(flag) │ Set the cancelled state │
│ │ associated with a status │
├───────────────────────┼────────────────────────────┤
│Set_elements(datatype, │ Set the number of elements │
│count) │ in a status │
└───────────────────────┴────────────────────────────┘
│Set_error(error) │ Set message error │
├───────────────────────┼────────────────────────────┤
│Set_source(source) │ Set message source │
├───────────────────────┼────────────────────────────┤
│Set_tag(tag) │ Set message tag │
├───────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────┼────────────────────────────┤
│py2f() │ │
└───────────────────────┴────────────────────────────┘
Attributes Summary
┌──────────┬─────────────────┐
│cancelled │ cancelled state │
├──────────┼─────────────────┤
│count │ byte count │
├──────────┼─────────────────┤
│error │ │
├──────────┼─────────────────┤
│source │ │
├──────────┼─────────────────┤
│tag │ │
└──────────┴─────────────────┘
Methods Documentation
Get_count(datatype=BYTE)
Get the number of top level elements
Parameters
datatype (Datatype) –
Return type
int
Get_elements(datatype)
Get the number of basic elements in a datatype
Parameters
datatype (Datatype) –
Return type
int
Get_error()
Get message error
Return type
int
Get_source()
Get message source
Return type
int
Get_tag()
Get message tag
Return type
int
Is_cancelled()
Test to see if a request was cancelled
Return type
bool
Set_cancelled(flag)
Set the cancelled state associated with a status
NOTE:
This should be only used when implementing query call-
back functions for generalized requests
Parameters
flag (bool) –
Return type
None
Set_elements(datatype, count)
Set the number of elements in a status
NOTE:
This should be only used when implementing query call-
back functions for generalized requests
Parameters
• datatype (Datatype) –
• count (int) –
Return type
None
Set_error(error)
Set message error
Parameters
error (int) –
Return type
None
Set_source(source)
Set message source
Parameters
source (int) –
Return type
None
Set_tag(tag)
Set message tag
Parameters
tag (int) –
Return type
None
classmethod f2py(arg)
Parameters
arg (List[int]) –
Return type
Status
py2f()
Return type
List[int]
Attributes Documentation
cancelled
cancelled state
count byte count
error
source
tag
mpi4py.MPI.Topocomm
class mpi4py.MPI.Topocomm(comm=None)
Bases: mpi4py.MPI.Intracomm
Topology intracommunicator
Parameters
comm (Optional[Topocomm]) –
Return type
Topocomm
static __new__(cls, comm=None)
Parameters
comm (Optional[Topocomm]) –
Return type
Topocomm
Methods Summary
┌──────────────────────────────┬────────────────────────────┐
│Ineighbor_allgather(sendbuf, │ Nonblocking Neighbor │
│recvbuf) │ Gather to All │
├──────────────────────────────┼────────────────────────────┤
│Ineighbor_allgatherv(sendbuf, │ Nonblocking Neighbor │
│recvbuf) │ Gather to All Vector │
├──────────────────────────────┼────────────────────────────┤
│Ineighbor_alltoall(sendbuf, │ Nonblocking Neighbor │
│recvbuf) │ All-to-All │
├──────────────────────────────┼────────────────────────────┤
│Ineighbor_alltoallv(sendbuf, │ Nonblocking Neighbor │
│recvbuf) │ All-to-All Vector │
├──────────────────────────────┼────────────────────────────┤
│Ineighbor_alltoallw(sendbuf, │ Nonblocking Neighbor │
│recvbuf) │ All-to-All Generalized │
├──────────────────────────────┼────────────────────────────┤
│Neighbor_allgather(sendbuf, │ Neighbor Gather to All │
│recvbuf) │ │
├──────────────────────────────┼────────────────────────────┤
│Neighbor_allgatherv(sendbuf, │ Neighbor Gather to All │
│recvbuf) │ Vector │
├──────────────────────────────┼────────────────────────────┤
│Neighbor_alltoall(sendbuf, │ Neighbor All-to-All │
│recvbuf) │ │
├──────────────────────────────┼────────────────────────────┤
│Neighbor_alltoallv(sendbuf, │ Neighbor All-to-All Vector │
│recvbuf) │ │
├──────────────────────────────┼────────────────────────────┤
│Neighbor_alltoallw(sendbuf, │ Neighbor All-to-All Gener- │
│recvbuf) │ alized │
├──────────────────────────────┼────────────────────────────┤
│neighbor_allgather(sendobj) │ Neighbor Gather to All │
├──────────────────────────────┼────────────────────────────┤
│neighbor_alltoall(sendobj) │ Neighbor All to All Scat- │
│ │ ter/Gather │
└──────────────────────────────┴────────────────────────────┘
Attributes Summary
┌───────────┬────────────────────────────┐
│degrees │ number of incoming and │
│ │ outgoing neighbors │
├───────────┼────────────────────────────┤
│indegree │ number of incoming neigh- │
│ │ bors │
├───────────┼────────────────────────────┤
│inedges │ incoming neighbors │
├───────────┼────────────────────────────┤
│inoutedges │ incoming and outgoing │
│ │ neighbors │
├───────────┼────────────────────────────┤
│outdegree │ number of outgoing neigh- │
│ │ bors │
├───────────┼────────────────────────────┤
│outedges │ outgoing neighbors │
└───────────┴────────────────────────────┘
Methods Documentation
Ineighbor_allgather(sendbuf, recvbuf)
Nonblocking Neighbor Gather to All
Parameters
• sendbuf (BufSpec) –
• recvbuf (BufSpecB) –
Return type
Request
Ineighbor_allgatherv(sendbuf, recvbuf)
Nonblocking Neighbor Gather to All Vector
Parameters
• sendbuf (BufSpec) –
• recvbuf (BufSpecV) –
Return type
Request
Ineighbor_alltoall(sendbuf, recvbuf)
Nonblocking Neighbor All-to-All
Parameters
• sendbuf (BufSpecB) –
• recvbuf (BufSpecB) –
Return type
Request
Ineighbor_alltoallv(sendbuf, recvbuf)
Nonblocking Neighbor All-to-All Vector
Parameters
• sendbuf (BufSpecV) –
• recvbuf (BufSpecV) –
Return type
Request
Ineighbor_alltoallw(sendbuf, recvbuf)
Nonblocking Neighbor All-to-All Generalized
Parameters
• sendbuf (BufSpecW) –
• recvbuf (BufSpecW) –
Return type
Request
Neighbor_allgather(sendbuf, recvbuf)
Neighbor Gather to All
Parameters
• sendbuf (BufSpec) –
• recvbuf (BufSpecB) –
Return type
None
Neighbor_allgatherv(sendbuf, recvbuf)
Neighbor Gather to All Vector
Parameters
• sendbuf (BufSpec) –
• recvbuf (BufSpecV) –
Return type
None
Neighbor_alltoall(sendbuf, recvbuf)
Neighbor All-to-All
Parameters
• sendbuf (BufSpecB) –
• recvbuf (BufSpecB) –
Return type
None
Neighbor_alltoallv(sendbuf, recvbuf)
Neighbor All-to-All Vector
Parameters
• sendbuf (BufSpecV) –
• recvbuf (BufSpecV) –
Return type
None
Neighbor_alltoallw(sendbuf, recvbuf)
Neighbor All-to-All Generalized
Parameters
• sendbuf (BufSpecW) –
• recvbuf (BufSpecW) –
Return type
None
neighbor_allgather(sendobj)
Neighbor Gather to All
Parameters
sendobj (Any) –
Return type
List[Any]
neighbor_alltoall(sendobj)
Neighbor All to All Scatter/Gather
Parameters
sendobj (List[Any]) –
Return type
List[Any]
Attributes Documentation
degrees
number of incoming and outgoing neighbors
indegree
number of incoming neighbors
inedges
incoming neighbors
inoutedges
incoming and outgoing neighbors
outdegree
number of outgoing neighbors
outedges
outgoing neighbors
mpi4py.MPI.Win
class mpi4py.MPI.Win(win=None)
Bases: object
Window handle
Parameters
win (Optional[Win]) –
Return type
Win
static __new__(cls, win=None)
Parameters
win (Optional[Win]) –
Return type
Win
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│Accumulate(origin, tar- │ Accumulate data into the │
│get_rank[, target, op]) │ target process │
├───────────────────────────┼────────────────────────────┤
│Allocate(size[, disp_unit, │ Create an window object │
│info, comm]) │ for one-sided communica- │
│ │ tion │
├───────────────────────────┼────────────────────────────┤
│Allocate_shared(size[, │ Create an window object │
│disp_unit, info, comm]) │ for one-sided communica- │
│ │ tion │
├───────────────────────────┼────────────────────────────┤
│Attach(memory) │ Attach a local memory re- │
│ │ gion │
├───────────────────────────┼────────────────────────────┤
│Call_errhandler(errorcode) │ Call the error handler in- │
│ │ stalled on a window │
├───────────────────────────┼────────────────────────────┤
│Compare_and_swap(origin, │ Perform one-sided atomic │
│compare, result, ...) │ compare-and-swap │
├───────────────────────────┼────────────────────────────┤
│Complete() │ Completes an RMA opera- │
│ │ tions begun after an │
│ │ Win.Start() │
├───────────────────────────┼────────────────────────────┤
│Create(memory[, disp_unit, │ Create an window object │
│info, comm]) │ for one-sided communica- │
│ │ tion │
├───────────────────────────┼────────────────────────────┤
│Create_dynamic([info, │ Create an window object │
│comm]) │ for one-sided communica- │
│ │ tion │
├───────────────────────────┼────────────────────────────┤
│Create_keyval([copy_fn, │ Create a new attribute key │
│delete_fn, nopython]) │ for windows │
├───────────────────────────┼────────────────────────────┤
│Delete_attr(keyval) │ Delete attribute value as- │
│ │ sociated with a key │
├───────────────────────────┼────────────────────────────┤
│Detach(memory) │ Detach a local memory re- │
│ │ gion │
├───────────────────────────┼────────────────────────────┤
│Fence([assertion]) │ Perform an MPI fence syn- │
│ │ chronization on a window │
├───────────────────────────┼────────────────────────────┤
│Fetch_and_op(origin, re- │ Perform one-sided │
│sult, target_rank[, ...]) │ read-modify-write │
├───────────────────────────┼────────────────────────────┤
│Flush(rank) │ Complete all outstanding │
│ │ RMA operations at the │
│ │ given target │
├───────────────────────────┼────────────────────────────┤
│Flush_all() │ Complete all outstanding │
│ │ RMA operations at all tar- │
│ │ gets │
├───────────────────────────┼────────────────────────────┤
│Flush_local(rank) │ Complete locally all out- │
│ │ standing RMA operations at │
│ │ the given target │
├───────────────────────────┼────────────────────────────┤
│Flush_local_all() │ Complete locally all out- │
│ │ standing RMA opera- tions │
│ │ at all targets │
├───────────────────────────┼────────────────────────────┤
│Free() │ Free a window │
├───────────────────────────┼────────────────────────────┤
│Free_keyval(keyval) │ Free an attribute key for │
│ │ windows │
├───────────────────────────┼────────────────────────────┤
│Get(origin, target_rank[, │ Get data from a memory │
│target]) │ window on a remote │
│ │ process. │
├───────────────────────────┼────────────────────────────┤
│Get_accumulate(origin, re- │ Fetch-and-accumulate data │
│sult, target_rank) │ into the target process │
├───────────────────────────┼────────────────────────────┤
│Get_attr(keyval) │ Retrieve attribute value │
│ │ by key │
├───────────────────────────┼────────────────────────────┤
│Get_errhandler() │ Get the error handler for │
│ │ a window │
├───────────────────────────┼────────────────────────────┤
│Get_group() │ Return a duplicate of the │
│ │ group of the communicator │
│ │ used to create the window │
├───────────────────────────┼────────────────────────────┤
│Get_info() │ Return the hints for a │
│ │ windows that are currently │
│ │ in use │
└───────────────────────────┴────────────────────────────┘
│Get_name() │ Get the print name associ- │
│ │ ated with the window │
├───────────────────────────┼────────────────────────────┤
│Lock(rank[, lock_type, as- │ Begin an RMA access epoch │
│sertion]) │ at the target process │
├───────────────────────────┼────────────────────────────┤
│Lock_all([assertion]) │ Begin an RMA access epoch │
│ │ at all processes │
├───────────────────────────┼────────────────────────────┤
│Post(group[, assertion]) │ Start an RMA exposure │
│ │ epoch │
├───────────────────────────┼────────────────────────────┤
│Put(origin, target_rank[, │ Put data into a memory │
│target]) │ window on a remote │
│ │ process. │
├───────────────────────────┼────────────────────────────┤
│Raccumulate(origin, tar- │ Fetch-and-accumulate data │
│get_rank[, target, op]) │ into the target process │
├───────────────────────────┼────────────────────────────┤
│Rget(origin, target_rank[, │ Get data from a memory │
│target]) │ window on a remote │
│ │ process. │
├───────────────────────────┼────────────────────────────┤
│Rget_accumulate(origin, │ Accumulate data into the │
│result, target_rank) │ target process using re- │
│ │ mote memory access. │
├───────────────────────────┼────────────────────────────┤
│Rput(origin, target_rank[, │ Put data into a memory │
│target]) │ window on a remote │
│ │ process. │
├───────────────────────────┼────────────────────────────┤
│Set_attr(keyval, attrval) │ Store attribute value as- │
│ │ sociated with a key │
├───────────────────────────┼────────────────────────────┤
│Set_errhandler(errhandler) │ Set the error handler for │
│ │ a window │
├───────────────────────────┼────────────────────────────┤
│Set_info(info) │ Set new values for the │
│ │ hints associated with a │
│ │ window │
├───────────────────────────┼────────────────────────────┤
│Set_name(name) │ Set the print name associ- │
│ │ ated with the window │
├───────────────────────────┼────────────────────────────┤
│Shared_query(rank) │ Query the process-local │
│ │ address for remote memory │
│ │ segments created with │
│ │ Win.Allocate_shared() │
├───────────────────────────┼────────────────────────────┤
│Start(group[, assertion]) │ Start an RMA access epoch │
│ │ for MPI │
├───────────────────────────┼────────────────────────────┤
│Sync() │ Synchronize public and │
│ │ private copies of the │
│ │ given window │
├───────────────────────────┼────────────────────────────┤
│Test() │ Test whether an RMA expo- │
│ │ sure epoch has completed │
├───────────────────────────┼────────────────────────────┤
│Unlock(rank) │ Complete an RMA access │
│ │ epoch at the target │
│ │ process │
├───────────────────────────┼────────────────────────────┤
│Unlock_all() │ Complete an RMA access │
│ │ epoch at all processes │
├───────────────────────────┼────────────────────────────┤
│Wait() │ Complete an RMA exposure │
│ │ epoch begun with │
│ │ Win.Post() │
├───────────────────────────┼────────────────────────────┤
│f2py(arg) │ │
├───────────────────────────┼────────────────────────────┤
│py2f() │ │
├───────────────────────────┼────────────────────────────┤
│tomemory() │ Return window memory buf- │
│ │ fer │
└───────────────────────────┴────────────────────────────┘
Attributes Summary
┌───────┬──────────────────────┐
│attrs │ window attributes │
├───────┼──────────────────────┤
│flavor │ window create flavor │
├───────┼──────────────────────┤
│group │ window group │
├───────┼──────────────────────┤
│info │ window info │
├───────┼──────────────────────┤
│model │ window memory model │
├───────┼──────────────────────┤
│name │ window name │
└───────┴──────────────────────┘
Methods Documentation
Accumulate(origin, target_rank, target=None, op=SUM)
Accumulate data into the target process
Parameters
• origin (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
• op (Op) –
Return type
None
classmethod Allocate(size, disp_unit=1, info=INFO_NULL,
comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• size (int) –
• disp_unit (int) –
• info (Info) –
• comm (Intracomm) –
Return type
Win
classmethod Allocate_shared(size, disp_unit=1, info=INFO_NULL,
comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• size (int) –
• disp_unit (int) –
• info (Info) –
• comm (Intracomm) –
Return type
Win
Attach(memory)
Attach a local memory region
Parameters
memory (Buffer) –
Return type
None
Call_errhandler(errorcode)
Call the error handler installed on a window
Parameters
errorcode (int) –
Return type
None
Compare_and_swap(origin, compare, result, target_rank, tar-
get_disp=0)
Perform one-sided atomic compare-and-swap
Parameters
• origin (BufSpec) –
• compare (BufSpec) –
• result (BufSpec) –
• target_rank (int) –
• target_disp (int) –
Return type
None
Complete()
Completes an RMA operations begun after an Win.Start()
Return type
None
classmethod Create(memory, disp_unit=1, info=INFO_NULL,
comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• memory (Union[Buffer, Bottom, None]) –
• disp_unit (int) –
• info (Info) –
• comm (Intracomm) –
Return type
Win
classmethod Create_dynamic(info=INFO_NULL, comm=COMM_SELF)
Create an window object for one-sided communication
Parameters
• info (Info) –
• comm (Intracomm) –
Return type
Win
classmethod Create_keyval(copy_fn=None, delete_fn=None, nopy-
thon=False)
Create a new attribute key for windows
Parameters
• copy_fn (Optional[Callable[[Win, int, Any],
Any]]) –
• delete_fn (Optional[Callable[[Win, int, Any],
None]]) –
• nopython (bool) –
Return type
int
Delete_attr(keyval)
Delete attribute value associated with a key
Parameters
keyval (int) –
Return type
None
Detach(memory)
Detach a local memory region
Parameters
memory (Buffer) –
Return type
None
Fence(assertion=0)
Perform an MPI fence synchronization on a window
Parameters
assertion (int) –
Return type
None
Fetch_and_op(origin, result, target_rank, target_disp=0, op=SUM)
Perform one-sided read-modify-write
Parameters
• origin (BufSpec) –
• result (BufSpec) –
• target_rank (int) –
• target_disp (int) –
• op (Op) –
Return type
None
Flush(rank)
Complete all outstanding RMA operations at the given tar-
get
Parameters
rank (int) –
Return type
None
Flush_all()
Complete all outstanding RMA operations at all targets
Return type
None
Flush_local(rank)
Complete locally all outstanding RMA operations at the
given target
Parameters
rank (int) –
Return type
None
Flush_local_all()
Complete locally all outstanding RMA opera- tions at all
targets
Return type
None
Free() Free a window
Return type
None
classmethod Free_keyval(keyval)
Free an attribute key for windows
Parameters
keyval (int) –
Return type
int
Get(origin, target_rank, target=None)
Get data from a memory window on a remote process.
Parameters
• origin (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
Return type
None
Get_accumulate(origin, result, target_rank, target=None, op=SUM)
Fetch-and-accumulate data into the target process
Parameters
• origin (BufSpec) –
• result (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
• op (Op) –
Return type
None
Get_attr(keyval)
Retrieve attribute value by key
Parameters
keyval (int) –
Return type
Optional[Union[int, Any]]
Get_errhandler()
Get the error handler for a window
Return type
Errhandler
Get_group()
Return a duplicate of the group of the communicator used
to create the window
Return type
Group
Get_info()
Return the hints for a windows that are currently in use
Return type
Info
Get_name()
Get the print name associated with the window
Return type
str
Lock(rank, lock_type=LOCK_EXCLUSIVE, assertion=0)
Begin an RMA access epoch at the target process
Parameters
• rank (int) –
• lock_type (int) –
• assertion (int) –
Return type
None
Lock_all(assertion=0)
Begin an RMA access epoch at all processes
Parameters
assertion (int) –
Return type
None
Post(group, assertion=0)
Start an RMA exposure epoch
Parameters
• group (Group) –
• assertion (int) –
Return type
None
Put(origin, target_rank, target=None)
Put data into a memory window on a remote process.
Parameters
• origin (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
Return type
None
Raccumulate(origin, target_rank, target=None, op=SUM)
Fetch-and-accumulate data into the target process
Parameters
• origin (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
• op (Op) –
Return type
Request
Rget(origin, target_rank, target=None)
Get data from a memory window on a remote process.
Parameters
• origin (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
Return type
Request
Rget_accumulate(origin, result, target_rank, target=None,
op=SUM)
Accumulate data into the target process using remote mem-
ory access.
Parameters
• origin (BufSpec) –
• result (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
• op (Op) –
Return type
Request
Rput(origin, target_rank, target=None)
Put data into a memory window on a remote process.
Parameters
• origin (BufSpec) –
• target_rank (int) –
• target (Optional[TargetSpec]) –
Return type
Request
Set_attr(keyval, attrval)
Store attribute value associated with a key
Parameters
• keyval (int) –
• attrval (Any) –
Return type
None
Set_errhandler(errhandler)
Set the error handler for a window
Parameters
errhandler (Errhandler) –
Return type
None
Set_info(info)
Set new values for the hints associated with a window
Parameters
info (Info) –
Return type
None
Set_name(name)
Set the print name associated with the window
Parameters
name (str) –
Return type
None
Shared_query(rank)
Query the process-local address for remote memory seg-
ments created with Win.Allocate_shared()
Parameters
rank (int) –
Return type
Tuple[memory, int]
Start(group, assertion=0)
Start an RMA access epoch for MPI
Parameters
• group (Group) –
• assertion (int) –
Return type
None
Sync() Synchronize public and private copies of the given window
Return type
None
Test() Test whether an RMA exposure epoch has completed
Return type
bool
Unlock(rank)
Complete an RMA access epoch at the target process
Parameters
rank (int) –
Return type
None
Unlock_all()
Complete an RMA access epoch at all processes
Return type
None
Wait() Complete an RMA exposure epoch begun with Win.Post()
Return type
Literal[True]
classmethod f2py(arg)
Parameters
arg (int) –
Return type
Win
py2f()
Return type
int
tomemory()
Return window memory buffer
Return type
memory
Attributes Documentation
attrs window attributes
flavor window create flavor
group window group
info window info
model window memory model
name window name
mpi4py.MPI.memory
class mpi4py.MPI.memory(buf)
Bases: object
Memory buffer
Parameters
buf (Buffer) –
Return type
memory
static __new__(cls, buf)
Parameters
buf (Buffer) –
Return type
memory
Methods Summary
┌───────────────────────────┬────────────────────────────┐
│allocate(nbytes[, clear]) │ Memory allocation │
├───────────────────────────┼────────────────────────────┤
│fromaddress(address, │ Memory from address and │
│nbytes[, readonly]) │ size in bytes │
├───────────────────────────┼────────────────────────────┤
│frombuffer(obj[, read- │ Memory from buffer-like │
│only]) │ object │
├───────────────────────────┼────────────────────────────┤
│release() │ Release the underlying │
│ │ buffer exposed by the mem- │
│ │ ory object │
├───────────────────────────┼────────────────────────────┤
│tobytes([order]) │ Return the data in the │
│ │ buffer as a byte string │
├───────────────────────────┼────────────────────────────┤
│toreadonly() │ Return a readonly version │
│ │ of the memory object │
└───────────────────────────┴────────────────────────────┘
Attributes Summary
┌─────────┬────────────────────────────┐
│address │ Memory address │
├─────────┼────────────────────────────┤
│format │ A string with the format │
│ │ of each element │
├─────────┼────────────────────────────┤
│itemsize │ The size in bytes of each │
│ │ element │
├─────────┼────────────────────────────┤
│nbytes │ Memory size (in bytes) │
├─────────┼────────────────────────────┤
│obj │ The underlying object of │
│ │ the memory │
├─────────┼────────────────────────────┤
│readonly │ Boolean indicating whether │
│ │ the memory is read-only │
└─────────┴────────────────────────────┘
Methods Documentation
static allocate(nbytes, clear=False)
Memory allocation
Parameters
• nbytes (int) –
• clear (bool) –
Return type
memory
static fromaddress(address, nbytes, readonly=False)
Memory from address and size in bytes
Parameters
• address (int) –
• nbytes (int) –
• readonly (bool) –
Return type
memory
static frombuffer(obj, readonly=False)
Memory from buffer-like object
Parameters
• obj (Buffer) –
• readonly (bool) –
Return type
memory
release()
Release the underlying buffer exposed by the memory ob-
ject
Return type
None
tobytes(order=None)
Return the data in the buffer as a byte string
Parameters
order (Optional[str]) –
Return type
bytes
toreadonly()
Return a readonly version of the memory object
Return type
memory
Attributes Documentation
address
Memory address
format A string with the format of each element
itemsize
The size in bytes of each element
nbytes Memory size (in bytes)
obj The underlying object of the memory
readonly
Boolean indicating whether the memory is read-only
Exceptions
┌──────────────────┬─────────────────┐
│Exception([ierr]) │ Exception class │
└──────────────────┴─────────────────┘
mpi4py.MPI.Exception
exception mpi4py.MPI.Exception(ierr=SUCCESS)
Bases: RuntimeError
Exception class
Parameters
ierr (int) –
Return type
Exception
static __new__(cls, ierr=SUCCESS)
Parameters
ierr (int) –
Return type
Exception
Methods Summary
┌───────────────────┬──────────────┐
│Get_error_class() │ Error class │
├───────────────────┼──────────────┤
│Get_error_code() │ Error code │
├───────────────────┼──────────────┤
│Get_error_string() │ Error string │
└───────────────────┴──────────────┘
Attributes Summary
┌─────────────┬──────────────┐
│error_class │ error class │
├─────────────┼──────────────┤
│error_code │ error code │
├─────────────┼──────────────┤
│error_string │ error string │
└─────────────┴──────────────┘
Methods Documentation
Get_error_class()
Error class
Return type
int
Get_error_code()
Error code
Return type
int
Get_error_string()
Error string
Return type
str
Attributes Documentation
error_class
error class
error_code
error code
error_string
error string
Functions
┌───────────────────────────┬────────────────────────────┐
│Add_error_class() │ Add an error class to the │
│ │ known error classes │
├───────────────────────────┼────────────────────────────┤
│Add_error_code(errorclass) │ Add an error code to an │
│ │ error class │
├───────────────────────────┼────────────────────────────┤
│Add_error_string(error- │ Associate an error string │
│code, string) │ with an error class or er- │
│ │ rorcode │
├───────────────────────────┼────────────────────────────┤
│Aint_add(base, disp) │ Return the sum of base ad- │
│ │ dress and displacement │
├───────────────────────────┼────────────────────────────┤
│Aint_diff(addr1, addr2) │ Return the difference be- │
│ │ tween absolute addresses │
├───────────────────────────┼────────────────────────────┤
│Alloc_mem(size[, info]) │ Allocate memory for mes- │
│ │ sage passing and RMA │
├───────────────────────────┼────────────────────────────┤
│Attach_buffer(buf) │ Attach a user-provided │
│ │ buffer for sending in │
│ │ buffered mode │
├───────────────────────────┼────────────────────────────┤
│Close_port(port_name) │ Close a port │
├───────────────────────────┼────────────────────────────┤
│Compute_dims(nnodes, dims) │ Return a balanced distri- │
│ │ bution of processes per │
│ │ coordinate direction │
├───────────────────────────┼────────────────────────────┤
│Detach_buffer() │ Remove an existing at- │
│ │ tached buffer │
├───────────────────────────┼────────────────────────────┤
│Finalize() │ Terminate the MPI execu- │
│ │ tion environment │
├───────────────────────────┼────────────────────────────┤
│Free_mem(mem) │ Free memory allocated with │
│ │ Alloc_mem() │
├───────────────────────────┼────────────────────────────┤
│Get_address(location) │ Get the address of a loca- │
│ │ tion in memory │
├───────────────────────────┼────────────────────────────┤
│Get_error_class(errorcode) │ Convert an error code into │
│ │ an error class │
├───────────────────────────┼────────────────────────────┤
│Get_error_string(error- │ Return the error string │
│code) │ for a given error class or │
│ │ error code │
├───────────────────────────┼────────────────────────────┤
│Get_library_version() │ Obtain the version string │
│ │ of the MPI library │
├───────────────────────────┼────────────────────────────┤
│Get_processor_name() │ Obtain the name of the │
│ │ calling processor │
├───────────────────────────┼────────────────────────────┤
│Get_version() │ Obtain the version number │
│ │ of the MPI standard sup- │
│ │ ported by the implementa- │
│ │ tion as a tuple (version, │
│ │ subversion) │
└───────────────────────────┴────────────────────────────┘
│Init() │ Initialize the MPI execu- │
│ │ tion environment │
├───────────────────────────┼────────────────────────────┤
│Init_thread([required]) │ Initialize the MPI execu- │
│ │ tion environment │
├───────────────────────────┼────────────────────────────┤
│Is_finalized() │ Indicates whether Finalize │
│ │ has completed │
├───────────────────────────┼────────────────────────────┤
│Is_initialized() │ Indicates whether Init has │
│ │ been called │
├───────────────────────────┼────────────────────────────┤
│Is_thread_main() │ Indicate whether this │
│ │ thread called Init or │
│ │ Init_thread │
├───────────────────────────┼────────────────────────────┤
│Lookup_name(service_name[, │ Lookup a port name given a │
│info]) │ service name │
├───────────────────────────┼────────────────────────────┤
│Open_port([info]) │ Return an address that can │
│ │ be used to establish con- │
│ │ nections between groups of │
│ │ MPI processes │
├───────────────────────────┼────────────────────────────┤
│Pcontrol(level) │ Control profiling │
├───────────────────────────┼────────────────────────────┤
│Publish_name(service_name, │ Publish a service name │
│port_name[, info]) │ │
├───────────────────────────┼────────────────────────────┤
│Query_thread() │ Return the level of thread │
│ │ support provided by the │
│ │ MPI library │
├───────────────────────────┼────────────────────────────┤
│Register_datarep(datarep, │ Register user-defined data │
│read_fn, write_fn, ...) │ representations │
├───────────────────────────┼────────────────────────────┤
│Unpublish_name(ser- │ Unpublish a service name │
│vice_name, port_name[, │ │
│info]) │ │
├───────────────────────────┼────────────────────────────┤
│Wtick() │ Return the resolution of │
│ │ Wtime │
├───────────────────────────┼────────────────────────────┤
│Wtime() │ Return an elapsed time on │
│ │ the calling processor │
├───────────────────────────┼────────────────────────────┤
│get_vendor() │ Infomation about the un- │
│ │ derlying MPI implementa- │
│ │ tion │
└───────────────────────────┴────────────────────────────┘
mpi4py.MPI.Add_error_class
mpi4py.MPI.Add_error_class()
Add an error class to the known error classes
Return type
int
mpi4py.MPI.Add_error_code
mpi4py.MPI.Add_error_code(errorclass)
Add an error code to an error class
Parameters
errorclass (int) –
Return type
int
mpi4py.MPI.Add_error_string
mpi4py.MPI.Add_error_string(errorcode, string)
Associate an error string with an error class or errorcode
Parameters
• errorcode (int) –
• string (str) –
Return type
None
mpi4py.MPI.Aint_add
mpi4py.MPI.Aint_add(base, disp)
Return the sum of base address and displacement
Parameters
• base (int) –
• disp (int) –
Return type
int
mpi4py.MPI.Aint_diff
mpi4py.MPI.Aint_diff(addr1, addr2)
Return the difference between absolute addresses
Parameters
• addr1 (int) –
• addr2 (int) –
Return type
int
mpi4py.MPI.Alloc_mem
mpi4py.MPI.Alloc_mem(size, info=INFO_NULL)
Allocate memory for message passing and RMA
Parameters
• size (int) –
• info (Info) –
Return type
memory
mpi4py.MPI.Attach_buffer
mpi4py.MPI.Attach_buffer(buf)
Attach a user-provided buffer for sending in buffered mode
Parameters
buf (Buffer) –
Return type
None
mpi4py.MPI.Close_port
mpi4py.MPI.Close_port(port_name)
Close a port
Parameters
port_name (str) –
Return type
None
mpi4py.MPI.Compute_dims
mpi4py.MPI.Compute_dims(nnodes, dims)
Return a balanced distribution of processes per coordinate di-
rection
Parameters
• nnodes (int) –
• dims (Union[int, Sequence[int]]) –
Return type
List[int]
mpi4py.MPI.Detach_buffer
mpi4py.MPI.Detach_buffer()
Remove an existing attached buffer
Return type
Buffer
mpi4py.MPI.Finalize
mpi4py.MPI.Finalize()
Terminate the MPI execution environment
Return type
None
mpi4py.MPI.Free_mem
mpi4py.MPI.Free_mem(mem)
Free memory allocated with Alloc_mem()
Parameters
mem (memory) –
Return type
None
mpi4py.MPI.Get_address
mpi4py.MPI.Get_address(location)
Get the address of a location in memory
Parameters
location (Union[Buffer, Bottom]) –
Return type
int
mpi4py.MPI.Get_error_class
mpi4py.MPI.Get_error_class(errorcode)
Convert an error code into an error class
Parameters
errorcode (int) –
Return type
int
mpi4py.MPI.Get_error_string
mpi4py.MPI.Get_error_string(errorcode)
Return the error string for a given error class or error code
Parameters
errorcode (int) –
Return type
str
mpi4py.MPI.Get_library_version
mpi4py.MPI.Get_library_version()
Obtain the version string of the MPI library
Return type
str
mpi4py.MPI.Get_processor_name
mpi4py.MPI.Get_processor_name()
Obtain the name of the calling processor
Return type
str
mpi4py.MPI.Get_version
mpi4py.MPI.Get_version()
Obtain the version number of the MPI standard supported by the
implementation as a tuple (version, subversion)
Return type
Tuple[int, int]
mpi4py.MPI.Init
mpi4py.MPI.Init()
Initialize the MPI execution environment
Return type
None
mpi4py.MPI.Init_thread
mpi4py.MPI.Init_thread(required=THREAD_MULTIPLE)
Initialize the MPI execution environment
Parameters
required (int) –
Return type
int
mpi4py.MPI.Is_finalized
mpi4py.MPI.Is_finalized()
Indicates whether Finalize has completed
Return type
bool
mpi4py.MPI.Is_initialized
mpi4py.MPI.Is_initialized()
Indicates whether Init has been called
Return type
bool
mpi4py.MPI.Is_thread_main
mpi4py.MPI.Is_thread_main()
Indicate whether this thread called Init or Init_thread
Return type
bool
mpi4py.MPI.Lookup_name
mpi4py.MPI.Lookup_name(service_name, info=INFO_NULL)
Lookup a port name given a service name
Parameters
• service_name (str) –
• info (Info) –
Return type
str
mpi4py.MPI.Open_port
mpi4py.MPI.Open_port(info=INFO_NULL)
Return an address that can be used to establish connections be-
tween groups of MPI processes
Parameters
info (Info) –
Return type
str
mpi4py.MPI.Pcontrol
mpi4py.MPI.Pcontrol(level)
Control profiling
Parameters
level (int) –
Return type
None
mpi4py.MPI.Publish_name
mpi4py.MPI.Publish_name(service_name, port_name, info=INFO_NULL)
Publish a service name
Parameters
• service_name (str) –
• port_name (str) –
• info (Info) –
Return type
None
mpi4py.MPI.Query_thread
mpi4py.MPI.Query_thread()
Return the level of thread support provided by the MPI library
Return type
int
mpi4py.MPI.Register_datarep
mpi4py.MPI.Register_datarep(datarep, read_fn, write_fn, extent_fn)
Register user-defined data representations
Parameters
• datarep (str) –
• read_fn (Callable[[Buffer, Datatype, int, Buffer, int],
None]) –
• write_fn (Callable[[Buffer, Datatype, int, Buffer,
int], None]) –
• extent_fn (Callable[[Datatype], int]) –
Return type
None
mpi4py.MPI.Unpublish_name
mpi4py.MPI.Unpublish_name(service_name, port_name, info=INFO_NULL)
Unpublish a service name
Parameters
• service_name (str) –
• port_name (str) –
• info (Info) –
Return type
None
mpi4py.MPI.Wtick
mpi4py.MPI.Wtick()
Return the resolution of Wtime
Return type
float
mpi4py.MPI.Wtime
mpi4py.MPI.Wtime()
Return an elapsed time on the calling processor
Return type
float
mpi4py.MPI.get_vendor
mpi4py.MPI.get_vendor()
Infomation about the underlying MPI implementation
Returns
• a string with the name of the MPI implementation
• an integer 3-tuple version (major, minor, micro)
Return type
Tuple[str, Tuple[int, int, int]]
Attributes
┌───────────────────────────┬────────────────────────────┐
│UNDEFINED │ int UNDEFINED │
├───────────────────────────┼────────────────────────────┤
│ANY_SOURCE │ int ANY_SOURCE │
├───────────────────────────┼────────────────────────────┤
│ANY_TAG │ int ANY_TAG │
├───────────────────────────┼────────────────────────────┤
│PROC_NULL │ int PROC_NULL │
├───────────────────────────┼────────────────────────────┤
│ROOT │ int ROOT │
├───────────────────────────┼────────────────────────────┤
│BOTTOM │ Bottom BOTTOM │
└───────────────────────────┴────────────────────────────┘
│IN_PLACE │ InPlace IN_PLACE │
├───────────────────────────┼────────────────────────────┤
│KEYVAL_INVALID │ int KEYVAL_INVALID │
├───────────────────────────┼────────────────────────────┤
│TAG_UB │ int TAG_UB │
├───────────────────────────┼────────────────────────────┤
│HOST │ int HOST │
├───────────────────────────┼────────────────────────────┤
│IO │ int IO │
├───────────────────────────┼────────────────────────────┤
│WTIME_IS_GLOBAL │ int WTIME_IS_GLOBAL │
├───────────────────────────┼────────────────────────────┤
│UNIVERSE_SIZE │ int UNIVERSE_SIZE │
├───────────────────────────┼────────────────────────────┤
│APPNUM │ int APPNUM │
├───────────────────────────┼────────────────────────────┤
│LASTUSEDCODE │ int LASTUSEDCODE │
├───────────────────────────┼────────────────────────────┤
│WIN_BASE │ int WIN_BASE │
├───────────────────────────┼────────────────────────────┤
│WIN_SIZE │ int WIN_SIZE │
├───────────────────────────┼────────────────────────────┤
│WIN_DISP_UNIT │ int WIN_DISP_UNIT │
├───────────────────────────┼────────────────────────────┤
│WIN_CREATE_FLAVOR │ int WIN_CREATE_FLAVOR │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR │ int WIN_FLAVOR │
├───────────────────────────┼────────────────────────────┤
│WIN_MODEL │ int WIN_MODEL │
├───────────────────────────┼────────────────────────────┤
│SUCCESS │ int SUCCESS │
├───────────────────────────┼────────────────────────────┤
│ERR_LASTCODE │ int ERR_LASTCODE │
├───────────────────────────┼────────────────────────────┤
│ERR_COMM │ int ERR_COMM │
├───────────────────────────┼────────────────────────────┤
│ERR_GROUP │ int ERR_GROUP │
├───────────────────────────┼────────────────────────────┤
│ERR_TYPE │ int ERR_TYPE │
├───────────────────────────┼────────────────────────────┤
│ERR_REQUEST │ int ERR_REQUEST │
├───────────────────────────┼────────────────────────────┤
│ERR_OP │ int ERR_OP │
├───────────────────────────┼────────────────────────────┤
│ERR_BUFFER │ int ERR_BUFFER │
├───────────────────────────┼────────────────────────────┤
│ERR_COUNT │ int ERR_COUNT │
├───────────────────────────┼────────────────────────────┤
│ERR_TAG │ int ERR_TAG │
├───────────────────────────┼────────────────────────────┤
│ERR_RANK │ int ERR_RANK │
├───────────────────────────┼────────────────────────────┤
│ERR_ROOT │ int ERR_ROOT │
├───────────────────────────┼────────────────────────────┤
│ERR_TRUNCATE │ int ERR_TRUNCATE │
├───────────────────────────┼────────────────────────────┤
│ERR_IN_STATUS │ int ERR_IN_STATUS │
├───────────────────────────┼────────────────────────────┤
│ERR_PENDING │ int ERR_PENDING │
├───────────────────────────┼────────────────────────────┤
│ERR_TOPOLOGY │ int ERR_TOPOLOGY │
├───────────────────────────┼────────────────────────────┤
│ERR_DIMS │ int ERR_DIMS │
├───────────────────────────┼────────────────────────────┤
│ERR_ARG │ int ERR_ARG │
├───────────────────────────┼────────────────────────────┤
│ERR_OTHER │ int ERR_OTHER │
├───────────────────────────┼────────────────────────────┤
│ERR_UNKNOWN │ int ERR_UNKNOWN │
├───────────────────────────┼────────────────────────────┤
│ERR_INTERN │ int ERR_INTERN │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO │ int ERR_INFO │
├───────────────────────────┼────────────────────────────┤
│ERR_FILE │ int ERR_FILE │
├───────────────────────────┼────────────────────────────┤
│ERR_WIN │ int ERR_WIN │
├───────────────────────────┼────────────────────────────┤
│ERR_KEYVAL │ int ERR_KEYVAL │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO_KEY │ int ERR_INFO_KEY │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO_VALUE │ int ERR_INFO_VALUE │
├───────────────────────────┼────────────────────────────┤
│ERR_INFO_NOKEY │ int ERR_INFO_NOKEY │
├───────────────────────────┼────────────────────────────┤
│ERR_ACCESS │ int ERR_ACCESS │
├───────────────────────────┼────────────────────────────┤
│ERR_AMODE │ int ERR_AMODE │
├───────────────────────────┼────────────────────────────┤
│ERR_BAD_FILE │ int ERR_BAD_FILE │
├───────────────────────────┼────────────────────────────┤
│ERR_FILE_EXISTS │ int ERR_FILE_EXISTS │
├───────────────────────────┼────────────────────────────┤
│ERR_FILE_IN_USE │ int ERR_FILE_IN_USE │
├───────────────────────────┼────────────────────────────┤
│ERR_NO_SPACE │ int ERR_NO_SPACE │
├───────────────────────────┼────────────────────────────┤
│ERR_NO_SUCH_FILE │ int ERR_NO_SUCH_FILE │
├───────────────────────────┼────────────────────────────┤
│ERR_IO │ int ERR_IO │
├───────────────────────────┼────────────────────────────┤
│ERR_READ_ONLY │ int ERR_READ_ONLY │
├───────────────────────────┼────────────────────────────┤
│ERR_CONVERSION │ int ERR_CONVERSION │
├───────────────────────────┼────────────────────────────┤
│ERR_DUP_DATAREP │ int ERR_DUP_DATAREP │
├───────────────────────────┼────────────────────────────┤
│ERR_UNSUPPORTED_DATAREP │ int ERR_UNSUP- │
│ │ PORTED_DATAREP │
├───────────────────────────┼────────────────────────────┤
│ERR_UNSUPPORTED_OPERATION │ int ERR_UNSUPPORTED_OPERA- │
│ │ TION │
├───────────────────────────┼────────────────────────────┤
│ERR_NAME │ int ERR_NAME │
├───────────────────────────┼────────────────────────────┤
│ERR_NO_MEM │ int ERR_NO_MEM │
├───────────────────────────┼────────────────────────────┤
│ERR_NOT_SAME │ int ERR_NOT_SAME │
├───────────────────────────┼────────────────────────────┤
│ERR_PORT │ int ERR_PORT │
├───────────────────────────┼────────────────────────────┤
│ERR_QUOTA │ int ERR_QUOTA │
├───────────────────────────┼────────────────────────────┤
│ERR_SERVICE │ int ERR_SERVICE │
├───────────────────────────┼────────────────────────────┤
│ERR_SPAWN │ int ERR_SPAWN │
├───────────────────────────┼────────────────────────────┤
│ERR_BASE │ int ERR_BASE │
├───────────────────────────┼────────────────────────────┤
│ERR_SIZE │ int ERR_SIZE │
└───────────────────────────┴────────────────────────────┘
│ERR_DISP │ int ERR_DISP │
├───────────────────────────┼────────────────────────────┤
│ERR_ASSERT │ int ERR_ASSERT │
├───────────────────────────┼────────────────────────────┤
│ERR_LOCKTYPE │ int ERR_LOCKTYPE │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_CONFLICT │ int ERR_RMA_CONFLICT │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_SYNC │ int ERR_RMA_SYNC │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_RANGE │ int ERR_RMA_RANGE │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_ATTACH │ int ERR_RMA_ATTACH │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_SHARED │ int ERR_RMA_SHARED │
├───────────────────────────┼────────────────────────────┤
│ERR_RMA_FLAVOR │ int ERR_RMA_FLAVOR │
├───────────────────────────┼────────────────────────────┤
│ORDER_C │ int ORDER_C │
├───────────────────────────┼────────────────────────────┤
│ORDER_FORTRAN │ int ORDER_FORTRAN │
├───────────────────────────┼────────────────────────────┤
│ORDER_F │ int ORDER_F │
├───────────────────────────┼────────────────────────────┤
│TYPECLASS_INTEGER │ int TYPECLASS_INTEGER │
├───────────────────────────┼────────────────────────────┤
│TYPECLASS_REAL │ int TYPECLASS_REAL │
├───────────────────────────┼────────────────────────────┤
│TYPECLASS_COMPLEX │ int TYPECLASS_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_NONE │ int DISTRIBUTE_NONE │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_BLOCK │ int DISTRIBUTE_BLOCK │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_CYCLIC │ int DISTRIBUTE_CYCLIC │
├───────────────────────────┼────────────────────────────┤
│DISTRIBUTE_DFLT_DARG │ int DISTRIBUTE_DFLT_DARG │
├───────────────────────────┼────────────────────────────┤
│COMBINER_NAMED │ int COMBINER_NAMED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_DUP │ int COMBINER_DUP │
├───────────────────────────┼────────────────────────────┤
│COMBINER_CONTIGUOUS │ int COMBINER_CONTIGUOUS │
├───────────────────────────┼────────────────────────────┤
│COMBINER_VECTOR │ int COMBINER_VECTOR │
├───────────────────────────┼────────────────────────────┤
│COMBINER_HVECTOR │ int COMBINER_HVECTOR │
├───────────────────────────┼────────────────────────────┤
│COMBINER_INDEXED │ int COMBINER_INDEXED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_HINDEXED │ int COMBINER_HINDEXED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_INDEXED_BLOCK │ int COMBINER_INDEXED_BLOCK │
├───────────────────────────┼────────────────────────────┤
│COMBINER_HINDEXED_BLOCK │ int COMBINER_HIN- │
│ │ DEXED_BLOCK │
├───────────────────────────┼────────────────────────────┤
│COMBINER_STRUCT │ int COMBINER_STRUCT │
├───────────────────────────┼────────────────────────────┤
│COMBINER_SUBARRAY │ int COMBINER_SUBARRAY │
├───────────────────────────┼────────────────────────────┤
│COMBINER_DARRAY │ int COMBINER_DARRAY │
├───────────────────────────┼────────────────────────────┤
│COMBINER_RESIZED │ int COMBINER_RESIZED │
├───────────────────────────┼────────────────────────────┤
│COMBINER_F90_REAL │ int COMBINER_F90_REAL │
├───────────────────────────┼────────────────────────────┤
│COMBINER_F90_COMPLEX │ int COMBINER_F90_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│COMBINER_F90_INTEGER │ int COMBINER_F90_INTEGER │
├───────────────────────────┼────────────────────────────┤
│IDENT │ int IDENT │
├───────────────────────────┼────────────────────────────┤
│CONGRUENT │ int CONGRUENT │
├───────────────────────────┼────────────────────────────┤
│SIMILAR │ int SIMILAR │
├───────────────────────────┼────────────────────────────┤
│UNEQUAL │ int UNEQUAL │
├───────────────────────────┼────────────────────────────┤
│CART │ int CART │
├───────────────────────────┼────────────────────────────┤
│GRAPH │ int GRAPH │
├───────────────────────────┼────────────────────────────┤
│DIST_GRAPH │ int DIST_GRAPH │
├───────────────────────────┼────────────────────────────┤
│UNWEIGHTED │ int UNWEIGHTED │
├───────────────────────────┼────────────────────────────┤
│WEIGHTS_EMPTY │ int WEIGHTS_EMPTY │
├───────────────────────────┼────────────────────────────┤
│COMM_TYPE_SHARED │ int COMM_TYPE_SHARED │
├───────────────────────────┼────────────────────────────┤
│BSEND_OVERHEAD │ int BSEND_OVERHEAD │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR_CREATE │ int WIN_FLAVOR_CREATE │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR_ALLOCATE │ int WIN_FLAVOR_ALLOCATE │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR_DYNAMIC │ int WIN_FLAVOR_DYNAMIC │
├───────────────────────────┼────────────────────────────┤
│WIN_FLAVOR_SHARED │ int WIN_FLAVOR_SHARED │
├───────────────────────────┼────────────────────────────┤
│WIN_SEPARATE │ int WIN_SEPARATE │
├───────────────────────────┼────────────────────────────┤
│WIN_UNIFIED │ int WIN_UNIFIED │
├───────────────────────────┼────────────────────────────┤
│MODE_NOCHECK │ int MODE_NOCHECK │
├───────────────────────────┼────────────────────────────┤
│MODE_NOSTORE │ int MODE_NOSTORE │
├───────────────────────────┼────────────────────────────┤
│MODE_NOPUT │ int MODE_NOPUT │
├───────────────────────────┼────────────────────────────┤
│MODE_NOPRECEDE │ int MODE_NOPRECEDE │
├───────────────────────────┼────────────────────────────┤
│MODE_NOSUCCEED │ int MODE_NOSUCCEED │
├───────────────────────────┼────────────────────────────┤
│LOCK_EXCLUSIVE │ int LOCK_EXCLUSIVE │
├───────────────────────────┼────────────────────────────┤
│LOCK_SHARED │ int LOCK_SHARED │
├───────────────────────────┼────────────────────────────┤
│MODE_RDONLY │ int MODE_RDONLY │
├───────────────────────────┼────────────────────────────┤
│MODE_WRONLY │ int MODE_WRONLY │
├───────────────────────────┼────────────────────────────┤
│MODE_RDWR │ int MODE_RDWR │
├───────────────────────────┼────────────────────────────┤
│MODE_CREATE │ int MODE_CREATE │
├───────────────────────────┼────────────────────────────┤
│MODE_EXCL │ int MODE_EXCL │
├───────────────────────────┼────────────────────────────┤
│MODE_DELETE_ON_CLOSE │ int MODE_DELETE_ON_CLOSE │
├───────────────────────────┼────────────────────────────┤
│MODE_UNIQUE_OPEN │ int MODE_UNIQUE_OPEN │
└───────────────────────────┴────────────────────────────┘
│MODE_SEQUENTIAL │ int MODE_SEQUENTIAL │
├───────────────────────────┼────────────────────────────┤
│MODE_APPEND │ int MODE_APPEND │
├───────────────────────────┼────────────────────────────┤
│SEEK_SET │ int SEEK_SET │
├───────────────────────────┼────────────────────────────┤
│SEEK_CUR │ int SEEK_CUR │
├───────────────────────────┼────────────────────────────┤
│SEEK_END │ int SEEK_END │
├───────────────────────────┼────────────────────────────┤
│DISPLACEMENT_CURRENT │ int DISPLACEMENT_CURRENT │
├───────────────────────────┼────────────────────────────┤
│DISP_CUR │ int DISP_CUR │
├───────────────────────────┼────────────────────────────┤
│THREAD_SINGLE │ int THREAD_SINGLE │
├───────────────────────────┼────────────────────────────┤
│THREAD_FUNNELED │ int THREAD_FUNNELED │
├───────────────────────────┼────────────────────────────┤
│THREAD_SERIALIZED │ int THREAD_SERIALIZED │
├───────────────────────────┼────────────────────────────┤
│THREAD_MULTIPLE │ int THREAD_MULTIPLE │
├───────────────────────────┼────────────────────────────┤
│VERSION │ int VERSION │
├───────────────────────────┼────────────────────────────┤
│SUBVERSION │ int SUBVERSION │
├───────────────────────────┼────────────────────────────┤
│MAX_PROCESSOR_NAME │ int MAX_PROCESSOR_NAME │
├───────────────────────────┼────────────────────────────┤
│MAX_ERROR_STRING │ int MAX_ERROR_STRING │
├───────────────────────────┼────────────────────────────┤
│MAX_PORT_NAME │ int MAX_PORT_NAME │
├───────────────────────────┼────────────────────────────┤
│MAX_INFO_KEY │ int MAX_INFO_KEY │
├───────────────────────────┼────────────────────────────┤
│MAX_INFO_VAL │ int MAX_INFO_VAL │
├───────────────────────────┼────────────────────────────┤
│MAX_OBJECT_NAME │ int MAX_OBJECT_NAME │
├───────────────────────────┼────────────────────────────┤
│MAX_DATAREP_STRING │ int MAX_DATAREP_STRING │
├───────────────────────────┼────────────────────────────┤
│MAX_LIBRARY_VERSION_STRING │ int MAX_LIBRARY_VER- │
│ │ SION_STRING │
├───────────────────────────┼────────────────────────────┤
│DATATYPE_NULL │ Datatype DATATYPE_NULL │
├───────────────────────────┼────────────────────────────┤
│UB │ Datatype UB │
├───────────────────────────┼────────────────────────────┤
│LB │ Datatype LB │
├───────────────────────────┼────────────────────────────┤
│PACKED │ Datatype PACKED │
├───────────────────────────┼────────────────────────────┤
│BYTE │ Datatype BYTE │
├───────────────────────────┼────────────────────────────┤
│AINT │ Datatype AINT │
├───────────────────────────┼────────────────────────────┤
│OFFSET │ Datatype OFFSET │
├───────────────────────────┼────────────────────────────┤
│COUNT │ Datatype COUNT │
├───────────────────────────┼────────────────────────────┤
│CHAR │ Datatype CHAR │
├───────────────────────────┼────────────────────────────┤
│WCHAR │ Datatype WCHAR │
├───────────────────────────┼────────────────────────────┤
│SIGNED_CHAR │ Datatype SIGNED_CHAR │
├───────────────────────────┼────────────────────────────┤
│SHORT │ Datatype SHORT │
├───────────────────────────┼────────────────────────────┤
│INT │ Datatype INT │
├───────────────────────────┼────────────────────────────┤
│LONG │ Datatype LONG │
├───────────────────────────┼────────────────────────────┤
│LONG_LONG │ Datatype LONG_LONG │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_CHAR │ Datatype UNSIGNED_CHAR │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_SHORT │ Datatype UNSIGNED_SHORT │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED │ Datatype UNSIGNED │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_LONG │ Datatype UNSIGNED_LONG │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_LONG_LONG │ Datatype UN- │
│ │ SIGNED_LONG_LONG │
├───────────────────────────┼────────────────────────────┤
│FLOAT │ Datatype FLOAT │
├───────────────────────────┼────────────────────────────┤
│DOUBLE │ Datatype DOUBLE │
├───────────────────────────┼────────────────────────────┤
│LONG_DOUBLE │ Datatype LONG_DOUBLE │
├───────────────────────────┼────────────────────────────┤
│C_BOOL │ Datatype C_BOOL │
├───────────────────────────┼────────────────────────────┤
│INT8_T │ Datatype INT8_T │
├───────────────────────────┼────────────────────────────┤
│INT16_T │ Datatype INT16_T │
├───────────────────────────┼────────────────────────────┤
│INT32_T │ Datatype INT32_T │
├───────────────────────────┼────────────────────────────┤
│INT64_T │ Datatype INT64_T │
├───────────────────────────┼────────────────────────────┤
│UINT8_T │ Datatype UINT8_T │
├───────────────────────────┼────────────────────────────┤
│UINT16_T │ Datatype UINT16_T │
├───────────────────────────┼────────────────────────────┤
│UINT32_T │ Datatype UINT32_T │
├───────────────────────────┼────────────────────────────┤
│UINT64_T │ Datatype UINT64_T │
├───────────────────────────┼────────────────────────────┤
│C_COMPLEX │ Datatype C_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│C_FLOAT_COMPLEX │ Datatype C_FLOAT_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│C_DOUBLE_COMPLEX │ Datatype C_DOUBLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│C_LONG_DOUBLE_COMPLEX │ Datatype C_LONG_DOU- │
│ │ BLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│CXX_BOOL │ Datatype CXX_BOOL │
├───────────────────────────┼────────────────────────────┤
│CXX_FLOAT_COMPLEX │ Datatype CXX_FLOAT_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│CXX_DOUBLE_COMPLEX │ Datatype CXX_DOUBLE_COM- │
│ │ PLEX │
├───────────────────────────┼────────────────────────────┤
│CXX_LONG_DOUBLE_COMPLEX │ Datatype CXX_LONG_DOU- │
│ │ BLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│SHORT_INT │ Datatype SHORT_INT │
├───────────────────────────┼────────────────────────────┤
│INT_INT │ Datatype INT_INT │
├───────────────────────────┼────────────────────────────┤
│TWOINT │ Datatype TWOINT │
└───────────────────────────┴────────────────────────────┘
│LONG_INT │ Datatype LONG_INT │
├───────────────────────────┼────────────────────────────┤
│FLOAT_INT │ Datatype FLOAT_INT │
├───────────────────────────┼────────────────────────────┤
│DOUBLE_INT │ Datatype DOUBLE_INT │
├───────────────────────────┼────────────────────────────┤
│LONG_DOUBLE_INT │ Datatype LONG_DOUBLE_INT │
├───────────────────────────┼────────────────────────────┤
│CHARACTER │ Datatype CHARACTER │
├───────────────────────────┼────────────────────────────┤
│LOGICAL │ Datatype LOGICAL │
├───────────────────────────┼────────────────────────────┤
│INTEGER │ Datatype INTEGER │
├───────────────────────────┼────────────────────────────┤
│REAL │ Datatype REAL │
├───────────────────────────┼────────────────────────────┤
│DOUBLE_PRECISION │ Datatype DOUBLE_PRECISION │
├───────────────────────────┼────────────────────────────┤
│COMPLEX │ Datatype COMPLEX │
├───────────────────────────┼────────────────────────────┤
│DOUBLE_COMPLEX │ Datatype DOUBLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│LOGICAL1 │ Datatype LOGICAL1 │
├───────────────────────────┼────────────────────────────┤
│LOGICAL2 │ Datatype LOGICAL2 │
├───────────────────────────┼────────────────────────────┤
│LOGICAL4 │ Datatype LOGICAL4 │
├───────────────────────────┼────────────────────────────┤
│LOGICAL8 │ Datatype LOGICAL8 │
├───────────────────────────┼────────────────────────────┤
│INTEGER1 │ Datatype INTEGER1 │
├───────────────────────────┼────────────────────────────┤
│INTEGER2 │ Datatype INTEGER2 │
├───────────────────────────┼────────────────────────────┤
│INTEGER4 │ Datatype INTEGER4 │
├───────────────────────────┼────────────────────────────┤
│INTEGER8 │ Datatype INTEGER8 │
├───────────────────────────┼────────────────────────────┤
│INTEGER16 │ Datatype INTEGER16 │
├───────────────────────────┼────────────────────────────┤
│REAL2 │ Datatype REAL2 │
├───────────────────────────┼────────────────────────────┤
│REAL4 │ Datatype REAL4 │
├───────────────────────────┼────────────────────────────┤
│REAL8 │ Datatype REAL8 │
├───────────────────────────┼────────────────────────────┤
│REAL16 │ Datatype REAL16 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX4 │ Datatype COMPLEX4 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX8 │ Datatype COMPLEX8 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX16 │ Datatype COMPLEX16 │
├───────────────────────────┼────────────────────────────┤
│COMPLEX32 │ Datatype COMPLEX32 │
├───────────────────────────┼────────────────────────────┤
│UNSIGNED_INT │ Datatype UNSIGNED_INT │
├───────────────────────────┼────────────────────────────┤
│SIGNED_SHORT │ Datatype SIGNED_SHORT │
├───────────────────────────┼────────────────────────────┤
│SIGNED_INT │ Datatype SIGNED_INT │
├───────────────────────────┼────────────────────────────┤
│SIGNED_LONG │ Datatype SIGNED_LONG │
├───────────────────────────┼────────────────────────────┤
│SIGNED_LONG_LONG │ Datatype SIGNED_LONG_LONG │
├───────────────────────────┼────────────────────────────┤
│BOOL │ Datatype BOOL │
├───────────────────────────┼────────────────────────────┤
│SINT8_T │ Datatype SINT8_T │
├───────────────────────────┼────────────────────────────┤
│SINT16_T │ Datatype SINT16_T │
├───────────────────────────┼────────────────────────────┤
│SINT32_T │ Datatype SINT32_T │
├───────────────────────────┼────────────────────────────┤
│SINT64_T │ Datatype SINT64_T │
├───────────────────────────┼────────────────────────────┤
│F_BOOL │ Datatype F_BOOL │
├───────────────────────────┼────────────────────────────┤
│F_INT │ Datatype F_INT │
├───────────────────────────┼────────────────────────────┤
│F_FLOAT │ Datatype F_FLOAT │
├───────────────────────────┼────────────────────────────┤
│F_DOUBLE │ Datatype F_DOUBLE │
├───────────────────────────┼────────────────────────────┤
│F_COMPLEX │ Datatype F_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│F_FLOAT_COMPLEX │ Datatype F_FLOAT_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│F_DOUBLE_COMPLEX │ Datatype F_DOUBLE_COMPLEX │
├───────────────────────────┼────────────────────────────┤
│REQUEST_NULL │ Request REQUEST_NULL │
├───────────────────────────┼────────────────────────────┤
│MESSAGE_NULL │ Message MESSAGE_NULL │
├───────────────────────────┼────────────────────────────┤
│MESSAGE_NO_PROC │ Message MESSAGE_NO_PROC │
├───────────────────────────┼────────────────────────────┤
│OP_NULL │ Op OP_NULL │
├───────────────────────────┼────────────────────────────┤
│MAX │ Op MAX │
├───────────────────────────┼────────────────────────────┤
│MIN │ Op MIN │
├───────────────────────────┼────────────────────────────┤
│SUM │ Op SUM │
├───────────────────────────┼────────────────────────────┤
│PROD │ Op PROD │
├───────────────────────────┼────────────────────────────┤
│LAND │ Op LAND │
├───────────────────────────┼────────────────────────────┤
│BAND │ Op BAND │
├───────────────────────────┼────────────────────────────┤
│LOR │ Op LOR │
├───────────────────────────┼────────────────────────────┤
│BOR │ Op BOR │
├───────────────────────────┼────────────────────────────┤
│LXOR │ Op LXOR │
├───────────────────────────┼────────────────────────────┤
│BXOR │ Op BXOR │
├───────────────────────────┼────────────────────────────┤
│MAXLOC │ Op MAXLOC │
├───────────────────────────┼────────────────────────────┤
│MINLOC │ Op MINLOC │
├───────────────────────────┼────────────────────────────┤
│REPLACE │ Op REPLACE │
├───────────────────────────┼────────────────────────────┤
│NO_OP │ Op NO_OP │
├───────────────────────────┼────────────────────────────┤
│GROUP_NULL │ Group GROUP_NULL │
├───────────────────────────┼────────────────────────────┤
│GROUP_EMPTY │ Group GROUP_EMPTY │
├───────────────────────────┼────────────────────────────┤
│INFO_NULL │ Info INFO_NULL │
└───────────────────────────┴────────────────────────────┘
│INFO_ENV │ Info INFO_ENV │
├───────────────────────────┼────────────────────────────┤
│ERRHANDLER_NULL │ Errhandler ERRHANDLER_NULL │
├───────────────────────────┼────────────────────────────┤
│ERRORS_RETURN │ Errhandler ERRORS_RETURN │
├───────────────────────────┼────────────────────────────┤
│ERRORS_ARE_FATAL │ Errhandler ERRORS_ARE_FA- │
│ │ TAL │
├───────────────────────────┼────────────────────────────┤
│COMM_NULL │ Comm COMM_NULL │
├───────────────────────────┼────────────────────────────┤
│COMM_SELF │ Intracomm COMM_SELF │
├───────────────────────────┼────────────────────────────┤
│COMM_WORLD │ Intracomm COMM_WORLD │
├───────────────────────────┼────────────────────────────┤
│WIN_NULL │ Win WIN_NULL │
├───────────────────────────┼────────────────────────────┤
│FILE_NULL │ File FILE_NULL │
├───────────────────────────┼────────────────────────────┤
│pickle │ Pickle pickle │
└───────────────────────────┴────────────────────────────┘
mpi4py.MPI.UNDEFINED
mpi4py.MPI.UNDEFINED: int = UNDEFINED
int UNDEFINED
mpi4py.MPI.ANY_SOURCE
mpi4py.MPI.ANY_SOURCE: int = ANY_SOURCE
int ANY_SOURCE
mpi4py.MPI.ANY_TAG
mpi4py.MPI.ANY_TAG: int = ANY_TAG
int ANY_TAG
mpi4py.MPI.PROC_NULL
mpi4py.MPI.PROC_NULL: int = PROC_NULL
int PROC_NULL
mpi4py.MPI.ROOT
mpi4py.MPI.ROOT: int = ROOT
int ROOT
mpi4py.MPI.BOTTOM
mpi4py.MPI.BOTTOM: Bottom = BOTTOM
Bottom BOTTOM
mpi4py.MPI.IN_PLACE
mpi4py.MPI.IN_PLACE: InPlace = IN_PLACE
InPlace IN_PLACE
mpi4py.MPI.KEYVAL_INVALID
mpi4py.MPI.KEYVAL_INVALID: int = KEYVAL_INVALID
int KEYVAL_INVALID
mpi4py.MPI.TAG_UB
mpi4py.MPI.TAG_UB: int = TAG_UB
int TAG_UB
mpi4py.MPI.HOST
mpi4py.MPI.HOST: int = HOST
int HOST
mpi4py.MPI.IO
mpi4py.MPI.IO: int = IO
int IO
mpi4py.MPI.WTIME_IS_GLOBAL
mpi4py.MPI.WTIME_IS_GLOBAL: int = WTIME_IS_GLOBAL
int WTIME_IS_GLOBAL
mpi4py.MPI.UNIVERSE_SIZE
mpi4py.MPI.UNIVERSE_SIZE: int = UNIVERSE_SIZE
int UNIVERSE_SIZE
mpi4py.MPI.APPNUM
mpi4py.MPI.APPNUM: int = APPNUM
int APPNUM
mpi4py.MPI.LASTUSEDCODE
mpi4py.MPI.LASTUSEDCODE: int = LASTUSEDCODE
int LASTUSEDCODE
mpi4py.MPI.WIN_BASE
mpi4py.MPI.WIN_BASE: int = WIN_BASE
int WIN_BASE
mpi4py.MPI.WIN_SIZE
mpi4py.MPI.WIN_SIZE: int = WIN_SIZE
int WIN_SIZE
mpi4py.MPI.WIN_DISP_UNIT
mpi4py.MPI.WIN_DISP_UNIT: int = WIN_DISP_UNIT
int WIN_DISP_UNIT
mpi4py.MPI.WIN_CREATE_FLAVOR
mpi4py.MPI.WIN_CREATE_FLAVOR: int = WIN_CREATE_FLAVOR
int WIN_CREATE_FLAVOR
mpi4py.MPI.WIN_FLAVOR
mpi4py.MPI.WIN_FLAVOR: int = WIN_FLAVOR
int WIN_FLAVOR
mpi4py.MPI.WIN_MODEL
mpi4py.MPI.WIN_MODEL: int = WIN_MODEL
int WIN_MODEL
mpi4py.MPI.SUCCESS
mpi4py.MPI.SUCCESS: int = SUCCESS
int SUCCESS
mpi4py.MPI.ERR_LASTCODE
mpi4py.MPI.ERR_LASTCODE: int = ERR_LASTCODE
int ERR_LASTCODE
mpi4py.MPI.ERR_COMM
mpi4py.MPI.ERR_COMM: int = ERR_COMM
int ERR_COMM
mpi4py.MPI.ERR_GROUP
mpi4py.MPI.ERR_GROUP: int = ERR_GROUP
int ERR_GROUP
mpi4py.MPI.ERR_TYPE
mpi4py.MPI.ERR_TYPE: int = ERR_TYPE
int ERR_TYPE
mpi4py.MPI.ERR_REQUEST
mpi4py.MPI.ERR_REQUEST: int = ERR_REQUEST
int ERR_REQUEST
mpi4py.MPI.ERR_OP
mpi4py.MPI.ERR_OP: int = ERR_OP
int ERR_OP
mpi4py.MPI.ERR_BUFFER
mpi4py.MPI.ERR_BUFFER: int = ERR_BUFFER
int ERR_BUFFER
mpi4py.MPI.ERR_COUNT
mpi4py.MPI.ERR_COUNT: int = ERR_COUNT
int ERR_COUNT
mpi4py.MPI.ERR_TAG
mpi4py.MPI.ERR_TAG: int = ERR_TAG
int ERR_TAG
mpi4py.MPI.ERR_RANK
mpi4py.MPI.ERR_RANK: int = ERR_RANK
int ERR_RANK
mpi4py.MPI.ERR_ROOT
mpi4py.MPI.ERR_ROOT: int = ERR_ROOT
int ERR_ROOT
mpi4py.MPI.ERR_TRUNCATE
mpi4py.MPI.ERR_TRUNCATE: int = ERR_TRUNCATE
int ERR_TRUNCATE
mpi4py.MPI.ERR_IN_STATUS
mpi4py.MPI.ERR_IN_STATUS: int = ERR_IN_STATUS
int ERR_IN_STATUS
mpi4py.MPI.ERR_PENDING
mpi4py.MPI.ERR_PENDING: int = ERR_PENDING
int ERR_PENDING
mpi4py.MPI.ERR_TOPOLOGY
mpi4py.MPI.ERR_TOPOLOGY: int = ERR_TOPOLOGY
int ERR_TOPOLOGY
mpi4py.MPI.ERR_DIMS
mpi4py.MPI.ERR_DIMS: int = ERR_DIMS
int ERR_DIMS
mpi4py.MPI.ERR_ARG
mpi4py.MPI.ERR_ARG: int = ERR_ARG
int ERR_ARG
mpi4py.MPI.ERR_OTHER
mpi4py.MPI.ERR_OTHER: int = ERR_OTHER
int ERR_OTHER
mpi4py.MPI.ERR_UNKNOWN
mpi4py.MPI.ERR_UNKNOWN: int = ERR_UNKNOWN
int ERR_UNKNOWN
mpi4py.MPI.ERR_INTERN
mpi4py.MPI.ERR_INTERN: int = ERR_INTERN
int ERR_INTERN
mpi4py.MPI.ERR_INFO
mpi4py.MPI.ERR_INFO: int = ERR_INFO
int ERR_INFO
mpi4py.MPI.ERR_FILE
mpi4py.MPI.ERR_FILE: int = ERR_FILE
int ERR_FILE
mpi4py.MPI.ERR_WIN
mpi4py.MPI.ERR_WIN: int = ERR_WIN
int ERR_WIN
mpi4py.MPI.ERR_KEYVAL
mpi4py.MPI.ERR_KEYVAL: int = ERR_KEYVAL
int ERR_KEYVAL
mpi4py.MPI.ERR_INFO_KEY
mpi4py.MPI.ERR_INFO_KEY: int = ERR_INFO_KEY
int ERR_INFO_KEY
mpi4py.MPI.ERR_INFO_VALUE
mpi4py.MPI.ERR_INFO_VALUE: int = ERR_INFO_VALUE
int ERR_INFO_VALUE
mpi4py.MPI.ERR_INFO_NOKEY
mpi4py.MPI.ERR_INFO_NOKEY: int = ERR_INFO_NOKEY
int ERR_INFO_NOKEY
mpi4py.MPI.ERR_ACCESS
mpi4py.MPI.ERR_ACCESS: int = ERR_ACCESS
int ERR_ACCESS
mpi4py.MPI.ERR_AMODE
mpi4py.MPI.ERR_AMODE: int = ERR_AMODE
int ERR_AMODE
mpi4py.MPI.ERR_BAD_FILE
mpi4py.MPI.ERR_BAD_FILE: int = ERR_BAD_FILE
int ERR_BAD_FILE
mpi4py.MPI.ERR_FILE_EXISTS
mpi4py.MPI.ERR_FILE_EXISTS: int = ERR_FILE_EXISTS
int ERR_FILE_EXISTS
mpi4py.MPI.ERR_FILE_IN_USE
mpi4py.MPI.ERR_FILE_IN_USE: int = ERR_FILE_IN_USE
int ERR_FILE_IN_USE
mpi4py.MPI.ERR_NO_SPACE
mpi4py.MPI.ERR_NO_SPACE: int = ERR_NO_SPACE
int ERR_NO_SPACE
mpi4py.MPI.ERR_NO_SUCH_FILE
mpi4py.MPI.ERR_NO_SUCH_FILE: int = ERR_NO_SUCH_FILE
int ERR_NO_SUCH_FILE
mpi4py.MPI.ERR_IO
mpi4py.MPI.ERR_IO: int = ERR_IO
int ERR_IO
mpi4py.MPI.ERR_READ_ONLY
mpi4py.MPI.ERR_READ_ONLY: int = ERR_READ_ONLY
int ERR_READ_ONLY
mpi4py.MPI.ERR_CONVERSION
mpi4py.MPI.ERR_CONVERSION: int = ERR_CONVERSION
int ERR_CONVERSION
mpi4py.MPI.ERR_DUP_DATAREP
mpi4py.MPI.ERR_DUP_DATAREP: int = ERR_DUP_DATAREP
int ERR_DUP_DATAREP
mpi4py.MPI.ERR_UNSUPPORTED_DATAREP
mpi4py.MPI.ERR_UNSUPPORTED_DATAREP: int = ERR_UNSUPPORTED_DATAREP
int ERR_UNSUPPORTED_DATAREP
mpi4py.MPI.ERR_UNSUPPORTED_OPERATION
mpi4py.MPI.ERR_UNSUPPORTED_OPERATION: int = ERR_UNSUPPORTED_OPERATION
int ERR_UNSUPPORTED_OPERATION
mpi4py.MPI.ERR_NAME
mpi4py.MPI.ERR_NAME: int = ERR_NAME
int ERR_NAME
mpi4py.MPI.ERR_NO_MEM
mpi4py.MPI.ERR_NO_MEM: int = ERR_NO_MEM
int ERR_NO_MEM
mpi4py.MPI.ERR_NOT_SAME
mpi4py.MPI.ERR_NOT_SAME: int = ERR_NOT_SAME
int ERR_NOT_SAME
mpi4py.MPI.ERR_PORT
mpi4py.MPI.ERR_PORT: int = ERR_PORT
int ERR_PORT
mpi4py.MPI.ERR_QUOTA
mpi4py.MPI.ERR_QUOTA: int = ERR_QUOTA
int ERR_QUOTA
mpi4py.MPI.ERR_SERVICE
mpi4py.MPI.ERR_SERVICE: int = ERR_SERVICE
int ERR_SERVICE
mpi4py.MPI.ERR_SPAWN
mpi4py.MPI.ERR_SPAWN: int = ERR_SPAWN
int ERR_SPAWN
mpi4py.MPI.ERR_BASE
mpi4py.MPI.ERR_BASE: int = ERR_BASE
int ERR_BASE
mpi4py.MPI.ERR_SIZE
mpi4py.MPI.ERR_SIZE: int = ERR_SIZE
int ERR_SIZE
mpi4py.MPI.ERR_DISP
mpi4py.MPI.ERR_DISP: int = ERR_DISP
int ERR_DISP
mpi4py.MPI.ERR_ASSERT
mpi4py.MPI.ERR_ASSERT: int = ERR_ASSERT
int ERR_ASSERT
mpi4py.MPI.ERR_LOCKTYPE
mpi4py.MPI.ERR_LOCKTYPE: int = ERR_LOCKTYPE
int ERR_LOCKTYPE
mpi4py.MPI.ERR_RMA_CONFLICT
mpi4py.MPI.ERR_RMA_CONFLICT: int = ERR_RMA_CONFLICT
int ERR_RMA_CONFLICT
mpi4py.MPI.ERR_RMA_SYNC
mpi4py.MPI.ERR_RMA_SYNC: int = ERR_RMA_SYNC
int ERR_RMA_SYNC
mpi4py.MPI.ERR_RMA_RANGE
mpi4py.MPI.ERR_RMA_RANGE: int = ERR_RMA_RANGE
int ERR_RMA_RANGE
mpi4py.MPI.ERR_RMA_ATTACH
mpi4py.MPI.ERR_RMA_ATTACH: int = ERR_RMA_ATTACH
int ERR_RMA_ATTACH
mpi4py.MPI.ERR_RMA_SHARED
mpi4py.MPI.ERR_RMA_SHARED: int = ERR_RMA_SHARED
int ERR_RMA_SHARED
mpi4py.MPI.ERR_RMA_FLAVOR
mpi4py.MPI.ERR_RMA_FLAVOR: int = ERR_RMA_FLAVOR
int ERR_RMA_FLAVOR
mpi4py.MPI.ORDER_C
mpi4py.MPI.ORDER_C: int = ORDER_C
int ORDER_C
mpi4py.MPI.ORDER_FORTRAN
mpi4py.MPI.ORDER_FORTRAN: int = ORDER_FORTRAN
int ORDER_FORTRAN
mpi4py.MPI.ORDER_F
mpi4py.MPI.ORDER_F: int = ORDER_F
int ORDER_F
mpi4py.MPI.TYPECLASS_INTEGER
mpi4py.MPI.TYPECLASS_INTEGER: int = TYPECLASS_INTEGER
int TYPECLASS_INTEGER
mpi4py.MPI.TYPECLASS_REAL
mpi4py.MPI.TYPECLASS_REAL: int = TYPECLASS_REAL
int TYPECLASS_REAL
mpi4py.MPI.TYPECLASS_COMPLEX
mpi4py.MPI.TYPECLASS_COMPLEX: int = TYPECLASS_COMPLEX
int TYPECLASS_COMPLEX
mpi4py.MPI.DISTRIBUTE_NONE
mpi4py.MPI.DISTRIBUTE_NONE: int = DISTRIBUTE_NONE
int DISTRIBUTE_NONE
mpi4py.MPI.DISTRIBUTE_BLOCK
mpi4py.MPI.DISTRIBUTE_BLOCK: int = DISTRIBUTE_BLOCK
int DISTRIBUTE_BLOCK
mpi4py.MPI.DISTRIBUTE_CYCLIC
mpi4py.MPI.DISTRIBUTE_CYCLIC: int = DISTRIBUTE_CYCLIC
int DISTRIBUTE_CYCLIC
mpi4py.MPI.DISTRIBUTE_DFLT_DARG
mpi4py.MPI.DISTRIBUTE_DFLT_DARG: int = DISTRIBUTE_DFLT_DARG
int DISTRIBUTE_DFLT_DARG
mpi4py.MPI.COMBINER_NAMED
mpi4py.MPI.COMBINER_NAMED: int = COMBINER_NAMED
int COMBINER_NAMED
mpi4py.MPI.COMBINER_DUP
mpi4py.MPI.COMBINER_DUP: int = COMBINER_DUP
int COMBINER_DUP
mpi4py.MPI.COMBINER_CONTIGUOUS
mpi4py.MPI.COMBINER_CONTIGUOUS: int = COMBINER_CONTIGUOUS
int COMBINER_CONTIGUOUS
mpi4py.MPI.COMBINER_VECTOR
mpi4py.MPI.COMBINER_VECTOR: int = COMBINER_VECTOR
int COMBINER_VECTOR
mpi4py.MPI.COMBINER_HVECTOR
mpi4py.MPI.COMBINER_HVECTOR: int = COMBINER_HVECTOR
int COMBINER_HVECTOR
mpi4py.MPI.COMBINER_INDEXED
mpi4py.MPI.COMBINER_INDEXED: int = COMBINER_INDEXED
int COMBINER_INDEXED
mpi4py.MPI.COMBINER_HINDEXED
mpi4py.MPI.COMBINER_HINDEXED: int = COMBINER_HINDEXED
int COMBINER_HINDEXED
mpi4py.MPI.COMBINER_INDEXED_BLOCK
mpi4py.MPI.COMBINER_INDEXED_BLOCK: int = COMBINER_INDEXED_BLOCK
int COMBINER_INDEXED_BLOCK
mpi4py.MPI.COMBINER_HINDEXED_BLOCK
mpi4py.MPI.COMBINER_HINDEXED_BLOCK: int = COMBINER_HINDEXED_BLOCK
int COMBINER_HINDEXED_BLOCK
mpi4py.MPI.COMBINER_STRUCT
mpi4py.MPI.COMBINER_STRUCT: int = COMBINER_STRUCT
int COMBINER_STRUCT
mpi4py.MPI.COMBINER_SUBARRAY
mpi4py.MPI.COMBINER_SUBARRAY: int = COMBINER_SUBARRAY
int COMBINER_SUBARRAY
mpi4py.MPI.COMBINER_DARRAY
mpi4py.MPI.COMBINER_DARRAY: int = COMBINER_DARRAY
int COMBINER_DARRAY
mpi4py.MPI.COMBINER_RESIZED
mpi4py.MPI.COMBINER_RESIZED: int = COMBINER_RESIZED
int COMBINER_RESIZED
mpi4py.MPI.COMBINER_F90_REAL
mpi4py.MPI.COMBINER_F90_REAL: int = COMBINER_F90_REAL
int COMBINER_F90_REAL
mpi4py.MPI.COMBINER_F90_COMPLEX
mpi4py.MPI.COMBINER_F90_COMPLEX: int = COMBINER_F90_COMPLEX
int COMBINER_F90_COMPLEX
mpi4py.MPI.COMBINER_F90_INTEGER
mpi4py.MPI.COMBINER_F90_INTEGER: int = COMBINER_F90_INTEGER
int COMBINER_F90_INTEGER
mpi4py.MPI.IDENT
mpi4py.MPI.IDENT: int = IDENT
int IDENT
mpi4py.MPI.CONGRUENT
mpi4py.MPI.CONGRUENT: int = CONGRUENT
int CONGRUENT
mpi4py.MPI.SIMILAR
mpi4py.MPI.SIMILAR: int = SIMILAR
int SIMILAR
mpi4py.MPI.UNEQUAL
mpi4py.MPI.UNEQUAL: int = UNEQUAL
int UNEQUAL
mpi4py.MPI.CART
mpi4py.MPI.CART: int = CART
int CART
mpi4py.MPI.GRAPH
mpi4py.MPI.GRAPH: int = GRAPH
int GRAPH
mpi4py.MPI.DIST_GRAPH
mpi4py.MPI.DIST_GRAPH: int = DIST_GRAPH
int DIST_GRAPH
mpi4py.MPI.UNWEIGHTED
mpi4py.MPI.UNWEIGHTED: int = UNWEIGHTED
int UNWEIGHTED
mpi4py.MPI.WEIGHTS_EMPTY
mpi4py.MPI.WEIGHTS_EMPTY: int = WEIGHTS_EMPTY
int WEIGHTS_EMPTY
mpi4py.MPI.COMM_TYPE_SHARED
mpi4py.MPI.COMM_TYPE_SHARED: int = COMM_TYPE_SHARED
int COMM_TYPE_SHARED
mpi4py.MPI.BSEND_OVERHEAD
mpi4py.MPI.BSEND_OVERHEAD: int = BSEND_OVERHEAD
int BSEND_OVERHEAD
mpi4py.MPI.WIN_FLAVOR_CREATE
mpi4py.MPI.WIN_FLAVOR_CREATE: int = WIN_FLAVOR_CREATE
int WIN_FLAVOR_CREATE
mpi4py.MPI.WIN_FLAVOR_ALLOCATE
mpi4py.MPI.WIN_FLAVOR_ALLOCATE: int = WIN_FLAVOR_ALLOCATE
int WIN_FLAVOR_ALLOCATE
mpi4py.MPI.WIN_FLAVOR_DYNAMIC
mpi4py.MPI.WIN_FLAVOR_DYNAMIC: int = WIN_FLAVOR_DYNAMIC
int WIN_FLAVOR_DYNAMIC
mpi4py.MPI.WIN_FLAVOR_SHARED
mpi4py.MPI.WIN_FLAVOR_SHARED: int = WIN_FLAVOR_SHARED
int WIN_FLAVOR_SHARED
mpi4py.MPI.WIN_SEPARATE
mpi4py.MPI.WIN_SEPARATE: int = WIN_SEPARATE
int WIN_SEPARATE
mpi4py.MPI.WIN_UNIFIED
mpi4py.MPI.WIN_UNIFIED: int = WIN_UNIFIED
int WIN_UNIFIED
mpi4py.MPI.MODE_NOCHECK
mpi4py.MPI.MODE_NOCHECK: int = MODE_NOCHECK
int MODE_NOCHECK
mpi4py.MPI.MODE_NOSTORE
mpi4py.MPI.MODE_NOSTORE: int = MODE_NOSTORE
int MODE_NOSTORE
mpi4py.MPI.MODE_NOPUT
mpi4py.MPI.MODE_NOPUT: int = MODE_NOPUT
int MODE_NOPUT
mpi4py.MPI.MODE_NOPRECEDE
mpi4py.MPI.MODE_NOPRECEDE: int = MODE_NOPRECEDE
int MODE_NOPRECEDE
mpi4py.MPI.MODE_NOSUCCEED
mpi4py.MPI.MODE_NOSUCCEED: int = MODE_NOSUCCEED
int MODE_NOSUCCEED
mpi4py.MPI.LOCK_EXCLUSIVE
mpi4py.MPI.LOCK_EXCLUSIVE: int = LOCK_EXCLUSIVE
int LOCK_EXCLUSIVE
mpi4py.MPI.LOCK_SHARED
mpi4py.MPI.LOCK_SHARED: int = LOCK_SHARED
int LOCK_SHARED
mpi4py.MPI.MODE_RDONLY
mpi4py.MPI.MODE_RDONLY: int = MODE_RDONLY
int MODE_RDONLY
mpi4py.MPI.MODE_WRONLY
mpi4py.MPI.MODE_WRONLY: int = MODE_WRONLY
int MODE_WRONLY
mpi4py.MPI.MODE_RDWR
mpi4py.MPI.MODE_RDWR: int = MODE_RDWR
int MODE_RDWR
mpi4py.MPI.MODE_CREATE
mpi4py.MPI.MODE_CREATE: int = MODE_CREATE
int MODE_CREATE
mpi4py.MPI.MODE_EXCL
mpi4py.MPI.MODE_EXCL: int = MODE_EXCL
int MODE_EXCL
mpi4py.MPI.MODE_DELETE_ON_CLOSE
mpi4py.MPI.MODE_DELETE_ON_CLOSE: int = MODE_DELETE_ON_CLOSE
int MODE_DELETE_ON_CLOSE
mpi4py.MPI.MODE_UNIQUE_OPEN
mpi4py.MPI.MODE_UNIQUE_OPEN: int = MODE_UNIQUE_OPEN
int MODE_UNIQUE_OPEN
mpi4py.MPI.MODE_SEQUENTIAL
mpi4py.MPI.MODE_SEQUENTIAL: int = MODE_SEQUENTIAL
int MODE_SEQUENTIAL
mpi4py.MPI.MODE_APPEND
mpi4py.MPI.MODE_APPEND: int = MODE_APPEND
int MODE_APPEND
mpi4py.MPI.SEEK_SET
mpi4py.MPI.SEEK_SET: int = SEEK_SET
int SEEK_SET
mpi4py.MPI.SEEK_CUR
mpi4py.MPI.SEEK_CUR: int = SEEK_CUR
int SEEK_CUR
mpi4py.MPI.SEEK_END
mpi4py.MPI.SEEK_END: int = SEEK_END
int SEEK_END
mpi4py.MPI.DISPLACEMENT_CURRENT
mpi4py.MPI.DISPLACEMENT_CURRENT: int = DISPLACEMENT_CURRENT
int DISPLACEMENT_CURRENT
mpi4py.MPI.DISP_CUR
mpi4py.MPI.DISP_CUR: int = DISP_CUR
int DISP_CUR
mpi4py.MPI.THREAD_SINGLE
mpi4py.MPI.THREAD_SINGLE: int = THREAD_SINGLE
int THREAD_SINGLE
mpi4py.MPI.THREAD_FUNNELED
mpi4py.MPI.THREAD_FUNNELED: int = THREAD_FUNNELED
int THREAD_FUNNELED
mpi4py.MPI.THREAD_SERIALIZED
mpi4py.MPI.THREAD_SERIALIZED: int = THREAD_SERIALIZED
int THREAD_SERIALIZED
mpi4py.MPI.THREAD_MULTIPLE
mpi4py.MPI.THREAD_MULTIPLE: int = THREAD_MULTIPLE
int THREAD_MULTIPLE
mpi4py.MPI.VERSION
mpi4py.MPI.VERSION: int = VERSION
int VERSION
mpi4py.MPI.SUBVERSION
mpi4py.MPI.SUBVERSION: int = SUBVERSION
int SUBVERSION
mpi4py.MPI.MAX_PROCESSOR_NAME
mpi4py.MPI.MAX_PROCESSOR_NAME: int = MAX_PROCESSOR_NAME
int MAX_PROCESSOR_NAME
mpi4py.MPI.MAX_ERROR_STRING
mpi4py.MPI.MAX_ERROR_STRING: int = MAX_ERROR_STRING
int MAX_ERROR_STRING
mpi4py.MPI.MAX_PORT_NAME
mpi4py.MPI.MAX_PORT_NAME: int = MAX_PORT_NAME
int MAX_PORT_NAME
mpi4py.MPI.MAX_INFO_KEY
mpi4py.MPI.MAX_INFO_KEY: int = MAX_INFO_KEY
int MAX_INFO_KEY
mpi4py.MPI.MAX_INFO_VAL
mpi4py.MPI.MAX_INFO_VAL: int = MAX_INFO_VAL
int MAX_INFO_VAL
mpi4py.MPI.MAX_OBJECT_NAME
mpi4py.MPI.MAX_OBJECT_NAME: int = MAX_OBJECT_NAME
int MAX_OBJECT_NAME
mpi4py.MPI.MAX_DATAREP_STRING
mpi4py.MPI.MAX_DATAREP_STRING: int = MAX_DATAREP_STRING
int MAX_DATAREP_STRING
mpi4py.MPI.MAX_LIBRARY_VERSION_STRING
mpi4py.MPI.MAX_LIBRARY_VERSION_STRING: int = MAX_LIBRARY_VERSION_STRING
int MAX_LIBRARY_VERSION_STRING
mpi4py.MPI.DATATYPE_NULL
mpi4py.MPI.DATATYPE_NULL: Datatype = DATATYPE_NULL
Datatype DATATYPE_NULL
mpi4py.MPI.UB
mpi4py.MPI.UB: Datatype = UB
Datatype UB
mpi4py.MPI.LB
mpi4py.MPI.LB: Datatype = LB
Datatype LB
mpi4py.MPI.PACKED
mpi4py.MPI.PACKED: Datatype = PACKED
Datatype PACKED
mpi4py.MPI.BYTE
mpi4py.MPI.BYTE: Datatype = BYTE
Datatype BYTE
mpi4py.MPI.AINT
mpi4py.MPI.AINT: Datatype = AINT
Datatype AINT
mpi4py.MPI.OFFSET
mpi4py.MPI.OFFSET: Datatype = OFFSET
Datatype OFFSET
mpi4py.MPI.COUNT
mpi4py.MPI.COUNT: Datatype = COUNT
Datatype COUNT
mpi4py.MPI.CHAR
mpi4py.MPI.CHAR: Datatype = CHAR
Datatype CHAR
mpi4py.MPI.WCHAR
mpi4py.MPI.WCHAR: Datatype = WCHAR
Datatype WCHAR
mpi4py.MPI.SIGNED_CHAR
mpi4py.MPI.SIGNED_CHAR: Datatype = SIGNED_CHAR
Datatype SIGNED_CHAR
mpi4py.MPI.SHORT
mpi4py.MPI.SHORT: Datatype = SHORT
Datatype SHORT
mpi4py.MPI.INT
mpi4py.MPI.INT: Datatype = INT
Datatype INT
mpi4py.MPI.LONG
mpi4py.MPI.LONG: Datatype = LONG
Datatype LONG
mpi4py.MPI.LONG_LONG
mpi4py.MPI.LONG_LONG: Datatype = LONG_LONG
Datatype LONG_LONG
mpi4py.MPI.UNSIGNED_CHAR
mpi4py.MPI.UNSIGNED_CHAR: Datatype = UNSIGNED_CHAR
Datatype UNSIGNED_CHAR
mpi4py.MPI.UNSIGNED_SHORT
mpi4py.MPI.UNSIGNED_SHORT: Datatype = UNSIGNED_SHORT
Datatype UNSIGNED_SHORT
mpi4py.MPI.UNSIGNED
mpi4py.MPI.UNSIGNED: Datatype = UNSIGNED
Datatype UNSIGNED
mpi4py.MPI.UNSIGNED_LONG
mpi4py.MPI.UNSIGNED_LONG: Datatype = UNSIGNED_LONG
Datatype UNSIGNED_LONG
mpi4py.MPI.UNSIGNED_LONG_LONG
mpi4py.MPI.UNSIGNED_LONG_LONG: Datatype = UNSIGNED_LONG_LONG
Datatype UNSIGNED_LONG_LONG
mpi4py.MPI.FLOAT
mpi4py.MPI.FLOAT: Datatype = FLOAT
Datatype FLOAT
mpi4py.MPI.DOUBLE
mpi4py.MPI.DOUBLE: Datatype = DOUBLE
Datatype DOUBLE
mpi4py.MPI.LONG_DOUBLE
mpi4py.MPI.LONG_DOUBLE: Datatype = LONG_DOUBLE
Datatype LONG_DOUBLE
mpi4py.MPI.C_BOOL
mpi4py.MPI.C_BOOL: Datatype = C_BOOL
Datatype C_BOOL
mpi4py.MPI.INT8_T
mpi4py.MPI.INT8_T: Datatype = INT8_T
Datatype INT8_T
mpi4py.MPI.INT16_T
mpi4py.MPI.INT16_T: Datatype = INT16_T
Datatype INT16_T
mpi4py.MPI.INT32_T
mpi4py.MPI.INT32_T: Datatype = INT32_T
Datatype INT32_T
mpi4py.MPI.INT64_T
mpi4py.MPI.INT64_T: Datatype = INT64_T
Datatype INT64_T
mpi4py.MPI.UINT8_T
mpi4py.MPI.UINT8_T: Datatype = UINT8_T
Datatype UINT8_T
mpi4py.MPI.UINT16_T
mpi4py.MPI.UINT16_T: Datatype = UINT16_T
Datatype UINT16_T
mpi4py.MPI.UINT32_T
mpi4py.MPI.UINT32_T: Datatype = UINT32_T
Datatype UINT32_T
mpi4py.MPI.UINT64_T
mpi4py.MPI.UINT64_T: Datatype = UINT64_T
Datatype UINT64_T
mpi4py.MPI.C_COMPLEX
mpi4py.MPI.C_COMPLEX: Datatype = C_COMPLEX
Datatype C_COMPLEX
mpi4py.MPI.C_FLOAT_COMPLEX
mpi4py.MPI.C_FLOAT_COMPLEX: Datatype = C_FLOAT_COMPLEX
Datatype C_FLOAT_COMPLEX
mpi4py.MPI.C_DOUBLE_COMPLEX
mpi4py.MPI.C_DOUBLE_COMPLEX: Datatype = C_DOUBLE_COMPLEX
Datatype C_DOUBLE_COMPLEX
mpi4py.MPI.C_LONG_DOUBLE_COMPLEX
mpi4py.MPI.C_LONG_DOUBLE_COMPLEX: Datatype = C_LONG_DOUBLE_COMPLEX
Datatype C_LONG_DOUBLE_COMPLEX
mpi4py.MPI.CXX_BOOL
mpi4py.MPI.CXX_BOOL: Datatype = CXX_BOOL
Datatype CXX_BOOL
mpi4py.MPI.CXX_FLOAT_COMPLEX
mpi4py.MPI.CXX_FLOAT_COMPLEX: Datatype = CXX_FLOAT_COMPLEX
Datatype CXX_FLOAT_COMPLEX
mpi4py.MPI.CXX_DOUBLE_COMPLEX
mpi4py.MPI.CXX_DOUBLE_COMPLEX: Datatype = CXX_DOUBLE_COMPLEX
Datatype CXX_DOUBLE_COMPLEX
mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX
mpi4py.MPI.CXX_LONG_DOUBLE_COMPLEX: Datatype = CXX_LONG_DOUBLE_COMPLEX
Datatype CXX_LONG_DOUBLE_COMPLEX
mpi4py.MPI.SHORT_INT
mpi4py.MPI.SHORT_INT: Datatype = SHORT_INT
Datatype SHORT_INT
mpi4py.MPI.INT_INT
mpi4py.MPI.INT_INT: Datatype = INT_INT
Datatype INT_INT
mpi4py.MPI.TWOINT
mpi4py.MPI.TWOINT: Datatype = TWOINT
Datatype TWOINT
mpi4py.MPI.LONG_INT
mpi4py.MPI.LONG_INT: Datatype = LONG_INT
Datatype LONG_INT
mpi4py.MPI.FLOAT_INT
mpi4py.MPI.FLOAT_INT: Datatype = FLOAT_INT
Datatype FLOAT_INT
mpi4py.MPI.DOUBLE_INT
mpi4py.MPI.DOUBLE_INT: Datatype = DOUBLE_INT
Datatype DOUBLE_INT
mpi4py.MPI.LONG_DOUBLE_INT
mpi4py.MPI.LONG_DOUBLE_INT: Datatype = LONG_DOUBLE_INT
Datatype LONG_DOUBLE_INT
mpi4py.MPI.CHARACTER
mpi4py.MPI.CHARACTER: Datatype = CHARACTER
Datatype CHARACTER
mpi4py.MPI.LOGICAL
mpi4py.MPI.LOGICAL: Datatype = LOGICAL
Datatype LOGICAL
mpi4py.MPI.INTEGER
mpi4py.MPI.INTEGER: Datatype = INTEGER
Datatype INTEGER
mpi4py.MPI.REAL
mpi4py.MPI.REAL: Datatype = REAL
Datatype REAL
mpi4py.MPI.DOUBLE_PRECISION
mpi4py.MPI.DOUBLE_PRECISION: Datatype = DOUBLE_PRECISION
Datatype DOUBLE_PRECISION
mpi4py.MPI.COMPLEX
mpi4py.MPI.COMPLEX: Datatype = COMPLEX
Datatype COMPLEX
mpi4py.MPI.DOUBLE_COMPLEX
mpi4py.MPI.DOUBLE_COMPLEX: Datatype = DOUBLE_COMPLEX
Datatype DOUBLE_COMPLEX
mpi4py.MPI.LOGICAL1
mpi4py.MPI.LOGICAL1: Datatype = LOGICAL1
Datatype LOGICAL1
mpi4py.MPI.LOGICAL2
mpi4py.MPI.LOGICAL2: Datatype = LOGICAL2
Datatype LOGICAL2
mpi4py.MPI.LOGICAL4
mpi4py.MPI.LOGICAL4: Datatype = LOGICAL4
Datatype LOGICAL4
mpi4py.MPI.LOGICAL8
mpi4py.MPI.LOGICAL8: Datatype = LOGICAL8
Datatype LOGICAL8
mpi4py.MPI.INTEGER1
mpi4py.MPI.INTEGER1: Datatype = INTEGER1
Datatype INTEGER1
mpi4py.MPI.INTEGER2
mpi4py.MPI.INTEGER2: Datatype = INTEGER2
Datatype INTEGER2
mpi4py.MPI.INTEGER4
mpi4py.MPI.INTEGER4: Datatype = INTEGER4
Datatype INTEGER4
mpi4py.MPI.INTEGER8
mpi4py.MPI.INTEGER8: Datatype = INTEGER8
Datatype INTEGER8
mpi4py.MPI.INTEGER16
mpi4py.MPI.INTEGER16: Datatype = INTEGER16
Datatype INTEGER16
mpi4py.MPI.REAL2
mpi4py.MPI.REAL2: Datatype = REAL2
Datatype REAL2
mpi4py.MPI.REAL4
mpi4py.MPI.REAL4: Datatype = REAL4
Datatype REAL4
mpi4py.MPI.REAL8
mpi4py.MPI.REAL8: Datatype = REAL8
Datatype REAL8
mpi4py.MPI.REAL16
mpi4py.MPI.REAL16: Datatype = REAL16
Datatype REAL16
mpi4py.MPI.COMPLEX4
mpi4py.MPI.COMPLEX4: Datatype = COMPLEX4
Datatype COMPLEX4
mpi4py.MPI.COMPLEX8
mpi4py.MPI.COMPLEX8: Datatype = COMPLEX8
Datatype COMPLEX8
mpi4py.MPI.COMPLEX16
mpi4py.MPI.COMPLEX16: Datatype = COMPLEX16
Datatype COMPLEX16
mpi4py.MPI.COMPLEX32
mpi4py.MPI.COMPLEX32: Datatype = COMPLEX32
Datatype COMPLEX32
mpi4py.MPI.UNSIGNED_INT
mpi4py.MPI.UNSIGNED_INT: Datatype = UNSIGNED_INT
Datatype UNSIGNED_INT
mpi4py.MPI.SIGNED_SHORT
mpi4py.MPI.SIGNED_SHORT: Datatype = SIGNED_SHORT
Datatype SIGNED_SHORT
mpi4py.MPI.SIGNED_INT
mpi4py.MPI.SIGNED_INT: Datatype = SIGNED_INT
Datatype SIGNED_INT
mpi4py.MPI.SIGNED_LONG
mpi4py.MPI.SIGNED_LONG: Datatype = SIGNED_LONG
Datatype SIGNED_LONG
mpi4py.MPI.SIGNED_LONG_LONG
mpi4py.MPI.SIGNED_LONG_LONG: Datatype = SIGNED_LONG_LONG
Datatype SIGNED_LONG_LONG
mpi4py.MPI.BOOL
mpi4py.MPI.BOOL: Datatype = BOOL
Datatype BOOL
mpi4py.MPI.SINT8_T
mpi4py.MPI.SINT8_T: Datatype = SINT8_T
Datatype SINT8_T
mpi4py.MPI.SINT16_T
mpi4py.MPI.SINT16_T: Datatype = SINT16_T
Datatype SINT16_T
mpi4py.MPI.SINT32_T
mpi4py.MPI.SINT32_T: Datatype = SINT32_T
Datatype SINT32_T
mpi4py.MPI.SINT64_T
mpi4py.MPI.SINT64_T: Datatype = SINT64_T
Datatype SINT64_T
mpi4py.MPI.F_BOOL
mpi4py.MPI.F_BOOL: Datatype = F_BOOL
Datatype F_BOOL
mpi4py.MPI.F_INT
mpi4py.MPI.F_INT: Datatype = F_INT
Datatype F_INT
mpi4py.MPI.F_FLOAT
mpi4py.MPI.F_FLOAT: Datatype = F_FLOAT
Datatype F_FLOAT
mpi4py.MPI.F_DOUBLE
mpi4py.MPI.F_DOUBLE: Datatype = F_DOUBLE
Datatype F_DOUBLE
mpi4py.MPI.F_COMPLEX
mpi4py.MPI.F_COMPLEX: Datatype = F_COMPLEX
Datatype F_COMPLEX
mpi4py.MPI.F_FLOAT_COMPLEX
mpi4py.MPI.F_FLOAT_COMPLEX: Datatype = F_FLOAT_COMPLEX
Datatype F_FLOAT_COMPLEX
mpi4py.MPI.F_DOUBLE_COMPLEX
mpi4py.MPI.F_DOUBLE_COMPLEX: Datatype = F_DOUBLE_COMPLEX
Datatype F_DOUBLE_COMPLEX
mpi4py.MPI.REQUEST_NULL
mpi4py.MPI.REQUEST_NULL: Request = REQUEST_NULL
Request REQUEST_NULL
mpi4py.MPI.MESSAGE_NULL
mpi4py.MPI.MESSAGE_NULL: Message = MESSAGE_NULL
Message MESSAGE_NULL
mpi4py.MPI.MESSAGE_NO_PROC
mpi4py.MPI.MESSAGE_NO_PROC: Message = MESSAGE_NO_PROC
Message MESSAGE_NO_PROC
mpi4py.MPI.OP_NULL
mpi4py.MPI.OP_NULL: Op = OP_NULL
Op OP_NULL
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.MAX
mpi4py.MPI.MAX: Op = MAX
Op MAX
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.MIN
mpi4py.MPI.MIN: Op = MIN
Op MIN
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.SUM
mpi4py.MPI.SUM: Op = SUM
Op SUM
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.PROD
mpi4py.MPI.PROD: Op = PROD
Op PROD
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.LAND
mpi4py.MPI.LAND: Op = LAND
Op LAND
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.BAND
mpi4py.MPI.BAND: Op = BAND
Op BAND
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.LOR
mpi4py.MPI.LOR: Op = LOR
Op LOR
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.BOR
mpi4py.MPI.BOR: Op = BOR
Op BOR
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.LXOR
mpi4py.MPI.LXOR: Op = LXOR
Op LXOR
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.BXOR
mpi4py.MPI.BXOR: Op = BXOR
Op BXOR
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.MAXLOC
mpi4py.MPI.MAXLOC: Op = MAXLOC
Op MAXLOC
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.MINLOC
mpi4py.MPI.MINLOC: Op = MINLOC
Op MINLOC
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.REPLACE
mpi4py.MPI.REPLACE: Op = REPLACE
Op REPLACE
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.NO_OP
mpi4py.MPI.NO_OP: Op = NO_OP
Op NO_OP
Parameters
• x (Any) –
• y (Any) –
Return type
Any
mpi4py.MPI.GROUP_NULL
mpi4py.MPI.GROUP_NULL: Group = GROUP_NULL
Group GROUP_NULL
mpi4py.MPI.GROUP_EMPTY
mpi4py.MPI.GROUP_EMPTY: Group = GROUP_EMPTY
Group GROUP_EMPTY
mpi4py.MPI.INFO_NULL
mpi4py.MPI.INFO_NULL: Info = INFO_NULL
Info INFO_NULL
mpi4py.MPI.INFO_ENV
mpi4py.MPI.INFO_ENV: Info = INFO_ENV
Info INFO_ENV
mpi4py.MPI.ERRHANDLER_NULL
mpi4py.MPI.ERRHANDLER_NULL: Errhandler = ERRHANDLER_NULL
Errhandler ERRHANDLER_NULL
mpi4py.MPI.ERRORS_RETURN
mpi4py.MPI.ERRORS_RETURN: Errhandler = ERRORS_RETURN
Errhandler ERRORS_RETURN
mpi4py.MPI.ERRORS_ARE_FATAL
mpi4py.MPI.ERRORS_ARE_FATAL: Errhandler = ERRORS_ARE_FATAL
Errhandler ERRORS_ARE_FATAL
mpi4py.MPI.COMM_NULL
mpi4py.MPI.COMM_NULL: Comm = COMM_NULL
Comm COMM_NULL
mpi4py.MPI.COMM_SELF
mpi4py.MPI.COMM_SELF: Intracomm = COMM_SELF
Intracomm COMM_SELF
mpi4py.MPI.COMM_WORLD
mpi4py.MPI.COMM_WORLD: Intracomm = COMM_WORLD
Intracomm COMM_WORLD
mpi4py.MPI.WIN_NULL
mpi4py.MPI.WIN_NULL: Win = WIN_NULL
Win WIN_NULL
mpi4py.MPI.FILE_NULL
mpi4py.MPI.FILE_NULL: File = FILE_NULL
File FILE_NULL
mpi4py.MPI.pickle
mpi4py.MPI.pickle: Pickle = <mpi4py.MPI.Pickle object>
Pickle pickle
CITATION
If MPI for Python been significant to a project that leads to an aca-
demic publication, please acknowledge that fact by citing the project.
• L. Dalcin and Y.-L. L. Fang, mpi4py: Status Update After 12 Years of
Development, Computing in Science & Engineering, 23(4):47-54, 2021.
https://doi.org/10.1109/MCSE.2021.3083216
• L. Dalcin, P. Kler, R. Paz, and A. Cosimo, Parallel Distributed Com-
puting using Python, Advances in Water Resources, 34(9):1124-1139,
2011. https://doi.org/10.1016/j.advwatres.2011.04.013
• L. Dalcin, R. Paz, M. Storti, and J. D’Elia, MPI for Python: perfor-
mance improvements and MPI-2 extensions, Journal of Parallel and Dis-
tributed Computing, 68(5):655-662, 2008.
https://doi.org/10.1016/j.jpdc.2007.09.005
• L. Dalcin, R. Paz, and M. Storti, MPI for Python, Journal of Parallel
and Distributed Computing, 65(9):1108-1115, 2005.
https://doi.org/10.1016/j.jpdc.2005.03.010
INSTALLATION
Requirements
You need to have the following software properly installed in order to
build MPI for Python:
• A working MPI implementation, preferably supporting MPI-3 and built
with shared/dynamic libraries.
NOTE:
If you want to build some MPI implementation from sources, check
the instructions at building-mpi in the appendix.
• Python 2.7, 3.5 or above.
NOTE:
Some MPI-1 implementations do require the actual command line ar-
guments to be passed in MPI_Init(). In this case, you will need to
use a rebuilt, MPI-enabled, Python interpreter executable. MPI for
Python has some support for alleviating you from this task. Check
the instructions at python-mpi in the appendix.
Using pip
If you already have a working MPI (either if you installed it from
sources or by using a pre-built package from your favourite GNU/Linux
distribution) and the mpicc compiler wrapper is on your search path,
you can use pip:
$ python -m pip install mpi4py
NOTE:
If the mpicc compiler wrapper is not on your search path (or if it
has a different name) you can use env to pass the environment vari-
able MPICC providing the full path to the MPI compiler wrapper exe-
cutable:
$ env MPICC=/path/to/mpicc python -m pip install mpi4py
WARNING:
pip keeps previouly built wheel files on its cache for future reuse.
If you want to reinstall the mpi4py package using a different or up-
dated MPI implementation, you have to either first remove the cached
wheel file with:
$ python -m pip cache remove mpi4py
or ask pip to disable the cache:
$ python -m pip install --no-cache-dir mpi4py
Using distutils
The MPI for Python package is available for download at the project
website generously hosted by GitHub. You can use curl or wget to get a
release tarball.
• Using curl:
$ curl -O https://github.com/mpi4py/mpi4py/releases/download/X.Y.Z/mpi4py-X.Y.Z.tar.gz
• Using wget:
$ wget https://github.com/mpi4py/mpi4py/releases/download/X.Y.Z/mpi4py-X.Y.Z.tar.gz
After unpacking the release tarball:
$ tar -zxf mpi4py-X.Y.Z.tar.gz
$ cd mpi4py-X.Y.Z
the package is ready for building.
MPI for Python uses a standard distutils-based build system. However,
some distutils commands (like build) have additional options:
--mpicc=
Lets you specify a special location or name for the mpicc com-
piler wrapper.
--mpi= Lets you pass a section with MPI configuration within a special
configuration file.
--configure
Runs exhaustive tests for checking about missing MPI types, con-
stants, and functions. This option should be passed in order to
build MPI for Python against old MPI-1 or MPI-2 implementations,
possibly providing a subset of MPI-3.
If you use a MPI implementation providing a mpicc compiler wrapper
(e.g., MPICH, Open MPI), it will be used for compilation and linking.
This is the preferred and easiest way of building MPI for Python.
If mpicc is located somewhere in your search path, simply run the build
command:
$ python setup.py build
If mpicc is not in your search path or the compiler wrapper has a dif-
ferent name, you can run the build command specifying its location:
$ python setup.py build --mpicc=/where/you/have/mpicc
Alternatively, you can provide all the relevant information about your
MPI implementation by editing the file called mpi.cfg. You can use the
default section [mpi] or add a new, custom section, for example
[other_mpi] (see the examples provided in the mpi.cfg file as a start-
ing point to write your own section):
[mpi]
include_dirs = /usr/local/mpi/include
libraries = mpi
library_dirs = /usr/local/mpi/lib
runtime_library_dirs = /usr/local/mpi/lib
[other_mpi]
include_dirs = /opt/mpi/include ...
libraries = mpi ...
library_dirs = /opt/mpi/lib ...
runtime_library_dirs = /op/mpi/lib ...
...
and then run the build command, perhaps specifying you custom configu-
ration section:
$ python setup.py build --mpi=other_mpi
After building, the package is ready for install.
If you have root privileges (either by log-in as the root user of by
using sudo) and you want to install MPI for Python in your system for
all users, just do:
$ python setup.py install
The previous steps will install the mpi4py package at standard location
prefix/lib/pythonX.X/site-packages.
If you do not have root privileges or you want to install MPI for
Python for your private use, just do:
$ python setup.py install --user
Testing
To quickly test the installation:
$ mpiexec -n 5 python -m mpi4py.bench helloworld
Hello, World! I am process 0 of 5 on localhost.
Hello, World! I am process 1 of 5 on localhost.
Hello, World! I am process 2 of 5 on localhost.
Hello, World! I am process 3 of 5 on localhost.
Hello, World! I am process 4 of 5 on localhost.
If you installed from source, issuing at the command line:
$ mpiexec -n 5 python demo/helloworld.py
or (in the case of ancient MPI-1 implementations):
$ mpirun -np 5 python `pwd`/demo/helloworld.py
will launch a five-process run of the Python interpreter and run the
test script demo/helloworld.py from the source distribution.
You can also run all the unittest scripts:
$ mpiexec -n 5 python test/runtests.py
or, if you have nose unit testing framework installed:
$ mpiexec -n 5 nosetests -w test
or, if you have py.test unit testing framework installed:
$ mpiexec -n 5 py.test test/
APPENDIX
MPI-enabled Python interpreter
WARNING:
These days it is no longer required to use the MPI-enabled
Python interpreter in most cases, and, therefore, it is not
built by default anymore because it is too difficult to reliably
build a Python interpreter across different distributions. If
you know that you still really need it, see below on how to use
the build_exe and install_exe commands.
Some MPI-1 implementations (notably, MPICH 1) do require the actual
command line arguments to be passed at the time MPI_Init() is called.
In this case, you will need to use a re-built, MPI-enabled, Python in-
terpreter binary executable. A basic implementation (targeting Python
2.X) of what is required is shown below:
#include <Python.h>
#include <mpi.h>
int main(int argc, char *argv[])
{
int status, flag;
MPI_Init(&argc, &argv);
status = Py_Main(argc, argv);
MPI_Finalized(&flag);
if (!flag) MPI_Finalize();
return status;
}
The source code above is straightforward; compiling it should also be.
However, the linking step is more tricky: special flags have to be
passed to the linker depending on your platform. In order to alleviate
you for such low-level details, MPI for Python provides some pure-dis-
tutils based support to build and install an MPI-enabled Python inter-
preter executable:
$ cd mpi4py-X.X.X
$ python setup.py build_exe [--mpi=<name>|--mpicc=/path/to/mpicc]
$ [sudo] python setup.py install_exe [--install-dir=$HOME/bin]
After the above steps you should have the MPI-enabled interpreter in-
stalled as prefix/bin/pythonX.X-mpi (or $HOME/bin/pythonX.X-mpi). As-
suming that prefix/bin (or $HOME/bin) is listed on your PATH, you
should be able to enter your MPI-enabled Python interactively, for ex-
ample:
$ python2.7-mpi
Python 2.7.8 (default, Nov 10 2014, 08:19:18)
[GCC 4.9.2 20141101 (Red Hat 4.9.2-1)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.executable
'/usr/bin/python2.7-mpi'
>>>
Building MPI from sources
In the list below you have some executive instructions for building
some of the open-source MPI implementations out there with support for
shared/dynamic libraries on POSIX environments.
• MPICH
$ tar -zxf mpich-X.X.X.tar.gz
$ cd mpich-X.X.X
$ ./configure --enable-shared --prefix=/usr/local/mpich
$ make
$ make install
• Open MPI
$ tar -zxf openmpi-X.X.X tar.gz
$ cd openmpi-X.X.X
$ ./configure --prefix=/usr/local/openmpi
$ make all
$ make install
• MPICH 1
$ tar -zxf mpich-X.X.X.tar.gz
$ cd mpich-X.X.X
$ ./configure --enable-sharedlib --prefix=/usr/local/mpich1
$ make
$ make install
Perhaps you will need to set the LD_LIBRARY_PATH environment variable
(using export, setenv or what applies to your system) pointing to the
directory containing the MPI libraries . In case of getting runtime
linking errors when running MPI programs, the following lines can be
added to the user login shell script (.profile, .bashrc, etc.).
• MPICH
MPI_DIR=/usr/local/mpich
export LD_LIBRARY_PATH=$MPI_DIR/lib:$LD_LIBRARY_PATH
• Open MPI
MPI_DIR=/usr/local/openmpi
export LD_LIBRARY_PATH=$MPI_DIR/lib:$LD_LIBRARY_PATH
• MPICH 1
MPI_DIR=/usr/local/mpich1
export LD_LIBRARY_PATH=$MPI_DIR/lib/shared:$LD_LIBRARY_PATH:
export MPICH_USE_SHLIB=yes
WARNING:
MPICH 1 support for dynamic libraries is not completely transpar-
ent. Users should set the environment variable MPICH_USE_SHLIB to
yes in order to avoid link problems when using the mpicc compiler
wrapper.
AUTHOR
Lisandro Dalcin
COPYRIGHT
2022, Lisandro Dalcin
3.1 March 16, 2022 MPI4PY(1)
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