2: #include <petscsys.h>         /*I  "petscsys.h"  I*/

  4: /*
  5:     Allows sending/receiving larger messages then 2 gigabytes in a single call
  6: */

  8: PetscErrorCode MPIULong_Send(void *mess,PetscInt cnt, MPI_Datatype type,PetscMPIInt to, PetscMPIInt tag, MPI_Comm comm)
  9: {
 10:   PetscErrorCode  ierr;
 11:   static PetscInt CHUNKSIZE = 250000000; /* 250,000,000 */
 12:   PetscInt        i,numchunks;
 13:   PetscMPIInt     icnt;

 16:   numchunks = cnt/CHUNKSIZE + 1;
 17:   for (i=0; i<numchunks; i++) {
 18:     icnt = PetscMPIIntCast((i < numchunks-1) ? CHUNKSIZE : cnt - (numchunks-1)*CHUNKSIZE);
 19:     MPI_Send(mess,icnt,type,to,tag,comm);
 20:     if (type == MPIU_INT) {
 21:       mess = (void*) (((PetscInt*)mess) + CHUNKSIZE);
 22:     } else if (type == MPIU_SCALAR) {
 23:       mess = (void*) (((PetscScalar*)mess) + CHUNKSIZE);
 24:     } else SETERRQ(comm,PETSC_ERR_SUP,"No support for this datatype");
 25:   }
 26:   return(0);
 27: }

 29: PetscErrorCode MPIULong_Recv(void *mess,PetscInt cnt, MPI_Datatype type,PetscMPIInt from, PetscMPIInt tag, MPI_Comm comm)
 30: {
 31:   int             ierr;
 32:   static PetscInt CHUNKSIZE = 250000000; /* 250,000,000 */
 33:   MPI_Status      status;
 34:   PetscInt        i,numchunks;
 35:   PetscMPIInt     icnt;

 38:   numchunks = cnt/CHUNKSIZE + 1;
 39:   for (i=0; i<numchunks; i++) {
 40:     icnt = PetscMPIIntCast((i < numchunks-1) ? CHUNKSIZE : cnt - (numchunks-1)*CHUNKSIZE);
 41:     MPI_Recv(mess,icnt,type,from,tag,comm,&status);
 42:     if (type == MPIU_INT) {
 43:       mess = (void*) (((PetscInt*)mess) + CHUNKSIZE);
 44:     } else if (type == MPIU_SCALAR) {
 45:       mess = (void*) (((PetscScalar*)mess) + CHUNKSIZE);
 46:     } else SETERRQ(comm,PETSC_ERR_SUP,"No support for this datatype");
 47:   }
 48:   return(0);
 49: }