Skip to content

Latest commit

 

History

History
111 lines (72 loc) · 2.78 KB

MPI_Group_range_incl.3.rst

File metadata and controls

111 lines (72 loc) · 2.78 KB
Raw

MPI_Group_range_incl

:ref:`MPI_Group_range_incl` |mdash| 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

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 expanding the array of ranges to an array of the included ranks and passing the resulting array of ranks and other arguments to :ref:`MPI_Group_incl`. A call to :ref:`MPI_Group_incl` is equivalent to a call to :ref:`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

.. seealso::
   * :ref:`MPI_Group_incl`
   * :ref:`MPI_Group_free`