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.

SEE ALSO

       MPI_Op_create