MPI_Group_range_incl(3) Open MPI MPI_Group_range_incl(3)
NAME
MPI_Group_range_incl - Creates a new group from ranges of ranks in an
existing group.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Group_range_incl(MPI_Group group, int n, int ranges[][3],
MPI_Group *newgroup)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GROUP_RANGE_INCL(GROUP, N, RANGES, NEWGROUP, IERROR)
INTEGER GROUP, N, RANGES(3,*), NEWGROUP, IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Group_range_incl(group, n, ranges, newgroup, ierror)
TYPE(MPI_Group), INTENT(IN) :: group
INTEGER, INTENT(IN) :: n, ranges(3,n)
TYPE(MPI_Group), INTENT(OUT) :: newgroup
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
#include <mpi.h>
Group Group::Range_incl(int n, const int ranges[][3]) const
INPUT PARAMETERS
group Group (handle).
n Number of triplets in array ranges (integer).
ranges A one-dimensional array of integer triplets, of the form
(first rank, last rank, stride) indicating ranks in group or
processes to be included in newgroup.
OUTPUT PARAMETERS
newgroup New group derived from above, in the order defined by ranges
(handle).
IERROR Fortran only: Error status (integer).
DESCRIPTION
If ranges consist of the triplets
(first1, last1, stride1), ..., (firstn, lastn, striden)
then newgroup consists of the sequence of processes in group with ranks
last(1)-first(1)
first(1), first(1) + stride(1),..., first(1) + ---------------- stride(1),...
stride(1)
last(n)-first(n)
first(n), first(n) + stride(n),..., first(n) + ---------------- stride(n).
stride(n)
Each computed rank must be a valid rank in group and all computed ranks
must be distinct, or else the program is erroneous. Note that we may
have first(i) > last(i), and stride(i) may be negative, but cannot be
zero.
The functionality of this routine is specified to be equivalent to ex-
panding the array of ranges to an array of the included ranks and pass-
ing the resulting array of ranks and other arguments to MPI_Group_incl.
A call to MPI_Group_incl is equivalent to a call to
MPI_Group_range_incl with each rank i in ranks replaced by the triplet
(i,i,1) in the argument ranges.
NOTE
This implementation does not currently check to see that the list of
ranges to include are valid ranks in the group.
ERRORS
Almost all MPI routines return an error value; C routines as the value
of the function and Fortran routines in the last argument. C++ func-
tions do not return errors. If the default error handler is set to
MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
will be used to throw an MPI::Exception object.
Before the error value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job, except for
I/O function errors. The error handler may be changed with
MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN
may be used to cause error values to be returned. Note that MPI does
not guarantee that an MPI program can continue past an error.
SEE ALSO
MPI_Group_incl
MPI_Group_free
4.1.2 Nov 24, 2021 MPI_Group_range_incl(3)
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