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, andthen 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 valueof the function and Fortran routines in the last argument. C++ func-
tions do not return errors. If the default error handler is set toMPI::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 withMPICommseterrhandler; 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)