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MPI_Group_size - Returns the size of a group.
 
 
#include <mpi.h>
int MPI_Group_size(MPI_Group group, int *size)
 
 
USE MPI
! or the older form: INCLUDE ’mpif.h’
MPI_GROUP_SIZE(GROUP, SIZE, IERROR)
    INTEGER    GROUP, SIZE, IERROR
 
 
USE mpi_f08
MPI_Group_size(group, size, ierror)
    TYPE(MPI_Group), INTENT(IN) :: group
    INTEGER, INTENT(OUT) :: size
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror
 
- group 
 
- Group (handle).
   
 
- size 
 
- Number of processes
in the group (integer). 
 
- IERROR 
 
- Fortran only: Error status (integer).
   
 
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.
 
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.
   
 
 
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