17.2.195. MPI_Group_translate_ranks

MPI_Group_translate_ranks - Translates the ranks of processes in one group to those in another group.

17.2.195.1. SYNTAX

17.2.195.1.1. C Syntax

#include <mpi.h>

int MPI_Group_translate_ranks(MPI_Group group1, int n,
     const int ranks1[], MPI_Group group2, int ranks2[])

17.2.195.1.2. Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GROUP_TRANSLATE_RANKS(GROUP1, N, RANKS1, GROUP2, RANKS2,
             IERROR)
     INTEGER GROUP1, N, RANKS1(*), GROUP2, RANKS2(*), IERROR

17.2.195.1.3. Fortran 2008 Syntax

USE mpi_f08
MPI_Group_translate_ranks(group1, n, ranks1, group2, ranks2, ierror)
     TYPE(MPI_Group), INTENT(IN) :: group1, group2
     INTEGER, INTENT(IN) :: n, ranks1(n)
     INTEGER, INTENT(OUT) :: ranks2(n)
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

17.2.195.2. INPUT PARAMETERS

  • group1: First group (handle).

  • n: Number of ranks in ranks1 and ranks2 arrays (integer).

  • ranks1: Array of zero or more valid ranks in group1.

  • group2: Second group (handle).

17.2.195.3. OUTPUT PARAMETERS

  • ranks2: Array of corresponding ranks in group2, MPI_UNDEFINED when no correspondence exists.

  • IERROR: Fortran only: Error status (integer).

17.2.195.4. DESCRIPTION

This function is important for determining the relative numbering of the same processes in two different groups. For instance, if one knows the ranks of certain processes in the group of MPI_COMM_WORLD, one might want to know their ranks in a subset of that group.

17.2.195.5. ERRORS

Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.

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.