Index: src/coll/intra_fns_new.c
===================================================================
RCS file: /MPIhome/mpich/src/coll/intra_fns_new.c,v
retrieving revision 1.20
retrieving revision 1.21
diff -r1.20 -r1.21
2c2
<  *  $Id: intra_fns_new.c,v 1.20 2002/12/04 23:01:04 thakur Exp $
---
>  *  $Id: intra_fns_new.c,v 1.21 2003/02/10 21:32:37 thakur Exp $
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<   int nprocs_completed, tmp_mask, tree_root;
---
>   int nprocs_completed, tmp_mask, tree_root, received;
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<               
---
> 
>           received = 0;
> 
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>               received = 1;
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>                       received = 1;
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< 
<                       if ((op_ptr->commute) || (dst_tree_root <
<                                                 my_tree_root)) { 
<                           (*uop)(tmp_recvbuf, tmp_results, &blklens[0],
<                                  &datatype->self); 
<                           (*uop)(((char *)tmp_recvbuf + dis[1]*extent),
<                                  ((char *)tmp_results + dis[1]*extent),
<                                  &blklens[1], &datatype->self); 
<                       }
<                       else {
<                           (*uop)(tmp_results, tmp_recvbuf, &blklens[0],
<                                  &datatype->self); 
<                           (*uop)(((char *)tmp_results + dis[1]*extent),
<                                  ((char *)tmp_recvbuf + dis[1]*extent),
<                                  &blklens[1], &datatype->self); 
<                           /* copy result back into tmp_results */
<                           mpi_errno = MPI_Sendrecv(tmp_recvbuf, 1,
<                                                    recvtype, rank, 
<                                                    MPIR_REDUCE_SCATTER_TAG, 
<                                                    tmp_results, 1,
<                                                    recvtype, rank, 
<                                                    MPIR_REDUCE_SCATTER_TAG, 
<                                                    comm->self, &status);
<                           if (mpi_errno) return mpi_errno;
<                       }
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<           /* the following could have been done just after the
<              MPI_Sendrecv above in the (if dst < size) case . however, 
<              for a noncommutative op, we would need an extra temp buffer so
<              as not to overwrite temp_recvbuf, because temp_recvbuf may have
---
>           /* The following reduction is done here instead of after 
>              the MPI_Sendrecv or MPI_Recv above. This is
>              because to do it above, in the noncommutative 
>              case, we would need an extra temp buffer so as not to
>              overwrite temp_recvbuf, because temp_recvbuf may have
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<           dst = rank ^ mask;
<           if (dst < size) {
---
>           if (received) {

.