NAME

MPI_Op_commutative - Query of commutativity of reduction operation.

SYNTAX

C Syntax

#include <mpi.h>
int MPI_Op_commutative(MPI_Op op, int *commute)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_OP_COMMUTATIVE(OP, COMMUTE, IERROR)
	LOGICAL	COMMUTE
	INTEGER	OP, IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_Op_commutative(op, commute, ierror)
	TYPE(MPI_Op), INTENT(IN) :: op
	INTEGER, INTENT(OUT) :: commute
	INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

#include <mpi.h>
bool Op::Is_commutative()

INPUT PARAMETER

op: Operation (handle).

OUTPUT PARAMETERS

commute: True if op is commutative, false otherwise (logical).
IERROR: Fortran only: Error status (integer).

DESCRIPTION

Reduction operations can be queried for their commutativity.

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++ functions 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.