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MPI_Group_size(3OpenMPI)                                                            MPI_Group_size(3OpenMPI)



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.




Open MPI 1.2                                   September 2006                       MPI_Group_size(3OpenMPI)