mpido_allgatherv.c

fortran并行计算包

                          dt_null,
                          recv_true_lb);


   if (sendbuf != MPI_IN_PLACE)
      MPIDI_Datatype_get_info(sendcount,
                              sendtype,
                              config.send_contig,
                              send_size,
                              dt_null,
                              send_true_lb);

   int buffer_sum = 0;
   {
      int i = 0;
      if (0 != displs[0])
         config.recv_continuous = 0;
      for (i = 1; i < comm_ptr->local_size; ++i)
      {
         buffer_sum += recvcounts[i - 1];
         if (buffer_sum != displs[i])
            config.recv_continuous = 0;
         if (!config.recv_continuous)
            break;
      }
      buffer_sum += recvcounts[comm_ptr->local_size - 1];
   }
   buffer_sum *= recv_size;

   MPIDO_Allreduce(MPI_IN_PLACE,
                   &config,
                   3,
                   MPI_INT,
                   MPI_BAND,
                   comm_ptr);

   /* determine which protocol to use */
   /* 1) Tree allreduce
   *     a) Need tree allreduce for this communicator
   *     b) User must be ok with allgatherv via allreduce
   *     c) Datatypes must be continguous
   *     d) Count must be a multiple of 4 since tree doesn't support
   *     chars right now
   */
   int treereduce = comm_ptr->dcmf.allreducetree &&
                    MPIDI_CollectiveProtocols.allgatherv.useallreduce &&
                    config.recv_contig && config.send_contig &&
                    config.recv_continuous && buffer_sum % 4 ==0;
   /* 2) Tree bcast
   *     a) Need tree bcast for this communicator
   *     b) User must be ok with allgatherv via bcast
   */     
   int treebcast = comm_ptr->dcmf.bcasttree &&
                   MPIDI_CollectiveProtocols.allgatherv.usebcast;

   /* 3) Alltoall
   *     a) Need torus alltoall for this communicator
   *     b) User must be ok with allgatherv via alltoall
   *     c) Need contiguous datatypes
   */
   int usealltoall = comm_ptr->dcmf.alltoalls &&
                     MPIDI_CollectiveProtocols.allgatherv.usealltoallv &&
                     config.recv_contig && config.send_contig;

#warning assume same cutoff for allgather
   if(treereduce && treebcast && sendcount > 65536)
   {
//      if(comm_ptr->rank ==0 )fprintf(stderr,"sendcount: %d, calling bcast\n", sendcount);
         result = MPIDO_Allgatherv_Bcast(sendbuf,
                                         sendcount,
                                         sendtype,
                                         recvbuf,
                                         recvcounts,
                                         displs,
                                         recvtype,
                                         comm_ptr);
                                         }
   else if(treereduce && treebcast && sendcount <= 65536)
   {
//      if(comm_ptr->rank ==0 )fprintf(stderr,"sendcount: %d, calling allreduce\n", sendcount);
         result = MPIDO_Allgatherv_Allreduce(sendbuf,
                                             sendcount,
                                             sendtype,
                                             recvbuf,
                                             recvcounts,
                                             displs,
                                             recvtype,
                                             comm_ptr,
                                             send_true_lb,
                                             recv_true_lb,
                                             send_size,
                                             recv_size,
                                             buffer_sum);
                                             }
   else if(treereduce)
   {
//      if(comm_ptr->rank ==0 )fprintf(stderr,"sendcount: %d, only tree allreduce\n", sendcount);

         result = MPIDO_Allgatherv_Allreduce(sendbuf,
                                             sendcount,
                                             sendtype,
                                             recvbuf,
                                             recvcounts,
                                             displs,
                                             recvtype,
                                             comm_ptr,
                                             send_true_lb,
                                             recv_true_lb,
                                             send_size,
                                             recv_size,
                                             buffer_sum);
                                             }
   else if(treebcast)
   {
//      if(comm_ptr->rank ==0 )fprintf(stderr,"sendcount: %d, only tree bcast\n", sendcount);
         result = MPIDO_Allgatherv_Bcast(sendbuf,
                                         sendcount,
                                         sendtype,
                                         recvbuf,
                                         recvcounts,
                                         displs,
                                         recvtype,
                                         comm_ptr);
                                       }
   else if(usealltoall)
         result = MPIDO_Allgatherv_Alltoall(sendbuf,
                                            sendcount,
                                            sendtype,
                                            recvbuf,
                                            recvcounts,
                                            displs,
                                            recvtype,
                                            comm_ptr,
                                            send_true_lb,
                                            recv_true_lb,
                                            recv_size);
   else
         return MPIR_Allgatherv(sendbuf,
                                sendcount,
                                sendtype,
                                recvbuf,
                                recvcounts,
                                displs,
                                recvtype,
                                comm_ptr);
   return result;
}

#if 0



   /* not worth doing on the torus */
   if (MPIDI_CollectiveProtocols.allgatherv.useallreduce &&
         comm_ptr->dcmf.allreducetree &&
         config.recv_contig &&
         config.send_contig &&
         config.recv_continuous &&
         buffer_sum % 4 == 0)
    {
      //if (0==comm_ptr->rank) puts("allreduce allgatherv");
      result = MPIDO_Allgatherv_Allreduce(sendbuf,
                                          sendcount,
                                          sendtype,
                                          recvbuf,
                                          recvcounts,
                                          displs,
                                          recvtype,
                                          comm_ptr,
                                          send_true_lb,
                                          recv_true_lb,
                                          send_size,
                                          recv_size,
                                          buffer_sum);
    }
    /* again, too slow if we only have a rectangle bcast */
   else if (MPIDI_CollectiveProtocols.allgatherv.usebcast &&
               comm_ptr->dcmf.bcasttree)
   {
      //if (0==comm_ptr->rank) puts("bcast allgatherv");
      result = MPIDO_Allgatherv_Bcast(sendbuf,
                                      sendcount,
                                      sendtype,
                                      recvbuf,
                                      recvcounts,
                                      displs,
                                      recvtype,
                                      comm_ptr);
   }
   else if (MPIDI_CollectiveProtocols.allgatherv.usealltoallv &&
               comm_ptr->dcmf.alltoalls &&
               config.recv_contig &&
               config.send_contig)
   {
      //if (0==comm_ptr->rank) puts("all2all allgatherv");
      result = MPIDO_Allgatherv_Alltoall(sendbuf,
                                         sendcount,
                                         sendtype,
                                         recvbuf,
                                         recvcounts,
                                         displs,
                                         recvtype,
                                         comm_ptr,
                                         send_true_lb,
                                         recv_true_lb,
                                         recv_size);
   }
   else
   {
      //if (0==comm_ptr->rank) puts("mpich2 allgatherv");
      return MPIR_Allgatherv(sendbuf,
                             sendcount,
                             sendtype,
                             recvbuf,
                             recvcounts,
                             displs,
                             recvtype,
                             comm_ptr);
   }

   return result;
}
#endif