openmpi/ompi/mpi/man/man3/MPI_Group_compare.md

Name

MPI_Group_compare - Compares two groups.

Syntax

C Syntax

#include <mpi.h>

int MPI_Group_compare(MPI_Group group1, MPI_Group group2,
    int *result)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'

MPI_GROUP_COMPARE(GROUP1, GROUP2, RESULT, IERROR)
    INTEGER	GROUP1, GROUP2, RESULT, IERROR

Fortran 2008 Syntax

USE mpi_f08

MPI_Group_compare(group1, group2, result, ierror)
    TYPE(MPI_Group), INTENT(IN) :: group1, group2
    INTEGER, INTENT(OUT) :: result
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

Input Parameters

• group1 : First group (handle).
• group2 : Second group (handle).

Output Parameters

• result : Integer which is MPI_IDENT if the order and members of the two groups are the same, MPI_SIMILAR if only the members are the same, and MPI_UNEQUAL otherwise.
• IERROR : Fortran only: Error status (integer).

Description

MPI_IDENT results if the group members and group order is exactly the same in both groups. This happens for instance if group1 and group2 are the same handle. MPI_SIMILAR results if the group members are the same but the order is different. MPI_UNEQUAL results otherwise.

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.