MPICommsize(3OpenMPI) MPICommsize(3OpenMPI)

NAME
       MMPPIICCoommmmssiizzee  - Returns the size of the group associated with a commu-
       nicator.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPICommsize(MPIComm comm, int *size)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPICOMMSIZE(COMM, SIZE, IERROR)
            INTEGER   COMM, SIZE, IERROR


CC++++ SSyynnttaaxx
       #include 
       int Comm::Getsize() const


IINNPPUUTT PPAARRAAMMEETTEERR
       comm      Communicator (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       size      Number of processes in the group of comm (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       This function indicates the number of processes involved in a  communi-
       cator.  For  MPICOMMWORLD, it indicates the total number of processes
       available. This function is equivalent to accessing the  communicator's
       group with MPICommgroup, computing the size using MPIGroupsize, and
       then freeing the temporary group via MPIGroupfree. If the  communica-
       tor   is  an  intra-communicator  (enables  communication  between  two
       groups), this function returns the size of the local group.  To  return
       the size of the remote group, use the MPICommremotesize function.

       This  call  is often used with MPICommrank to determine the amount of
       concurrency available for a specific library or program.  MPICommrank
       indicates  the rank of the process that calls it in the range from  0 .
       . . size-1, where size is the return value of MPICommsize.


NNOOTTEE
       MPICOMMNULL is not considered a valid argument to this function.


EERRRROORRSS
       Almost all MPI routines return an error value; C routines as the  value
       of  the  function  and Fortran routines in the last argument. C++ func-
       tions do not return errors. If the default  error  handler  is  set  to
       MPI::ERRORSTHROWEXCEPTIONS, 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
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       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
       MPICommgroup
       MPICommrank
       MPICommcompare




Open MPI 1.2                    September 2006         MPICommsize(3OpenMPI)