MPI_Group_size(3)                  Open MPI                  MPI_Group_size(3)



NAME
       MPI_Group_size - Returns the size of a group.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Group_size(MPI_Group group, int *size)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_GROUP_SIZE(GROUP, SIZE, IERROR)
            INTEGER   GROUP, SIZE, IERROR


C++ Syntax
       #include <mpi.h>
       int Group::Get_size() const


INPUT PARAMETERS
       group     Group (handle).


OUTPUT PARAMETERS
       size      Number of processes in the group (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPI_Group_size returns in size the number of processes in the group.
       Thus, if group = MPI_GROUP_EMPTY, then the call will return size = 0.
       On the other hand, a call with group = MPI_GROUP_NULL is erroneous.


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.




1.4.1                            Jan 14, 2010                MPI_Group_size(3)
