1: /*$Id: pcomm.c,v 1.24 2001/03/23 23:20:38 balay Exp $*/

 3:  #include petsc.h

  5: #undef __FUNCT__  
  7: /*@C 
  8:    PetscSetCommWorld - Sets a communicator to be PETSc world communicator
  9:    (default is MPI_COMM_WORLD).  Must call BEFORE PetscInitialize().

 11:    Collective on MPI_Comm

 13:    Input Parameter:
 14: .  comm - the communicator

 16:    Note:
 17:    This routine is intended for users who need to initialize PETSc on a
 18:    subset of processors within a larger job.  Thus, most users need not
 19:    call this routine.

 21:    Level: advanced

 23:    Concepts: communicator^setting for PETSc
 24:    Concepts: MPI communicator^setting for PETSc
 25:    Concepts: PETSC_COMM_WORLD^setting

 27: @*/
 28: int PetscSetCommWorld(MPI_Comm comm)
 29: {
 31:   if (PetscInitializeCalled) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Must call before PetscInitialize()");
 32:   PETSC_COMM_WORLD = comm;
 33:   return(0);
 34: }