Due to the last post in this thread this copy I suggested seems not to be
possible, but I also want to test whether this post goes through to the list
now.
-- Reuti
===
Hi,
> Am 19.04.2017 um 19:53 schrieb Jim Edwards <jedwa...@ucar.edu>:
>
> Hi,
>
> I have openmpi-2.0.2 builds on two different machines and I have a test code
> which works on one machine and does not on the other machine. I'm struggling
> to understand why and I hope that by posting here someone may have some
> insight.
>
> The test is using mpi derived data types and mpi_alltoallw on 4 tasks. On
> the machine that fails it appears to ignore the displacement in the derived
> datatype defined on task 0 and just send 0-3 to all tasks. The failing
> machine is built against gcc 5.4.0, the working machine has both intel 16.0.3
> and gcc 6.3.0 builds.
And what happens when you copy one compilation from one node to the other
(including all addressed shared libraries)?
-- Reuti
> #include "mpi.h"
>
> #include <stdio.h>
>
>
>
> int main(int argc, char *argv[])
>
> {
>
> int rank, size;
>
> MPI_Datatype type[4], type2[4];
>
> int displacement[1];
>
> int sbuffer[16];
>
> int rbuffer[4];
>
> MPI_Status status;
>
> int scnts[4], sdispls[4], rcnts[4], rdispls[4];
>
>
> MPI_Init(&argc, &argv);
>
> MPI_Comm_size(MPI_COMM_WORLD, &size);
>
> if (size < 4)
>
> {
>
> printf("Please run with 4 processes.\n");
>
> MPI_Finalize();
>
> return 1;
>
> }
>
> MPI_Comm_rank(MPI_COMM_WORLD, &rank);
>
>
>
> /* task 0 has sbuffer of size 16 and we are going to send 4 values to each
> of tasks 0-3, offsetting in each
>
> case so that the expected result is
>
> task[0] 0-3
>
> task[1] 4-7
>
> task[2] 8-11
>
> task[3] 12-15
>
> */
>
>
>
>
>
> for( int i=0; i<size; i++){
>
> if (rank == 0){
>
> scnts[i] = 1;
>
> }else{
>
> scnts[i] = 0;
>
> }
>
> sdispls[i] = 0;
>
> rcnts[i] = 0;
>
> rdispls[i] = 0;
>
> }
>
> rcnts[0] = 1;
>
>
> for (int i=0; i<size; i++){
>
> type[i] = MPI_INT;
>
> type2[i] = MPI_INT;
>
> rbuffer[i] = -1;
>
> }
>
> /* on the recv side we create a data type which is a single block of 4
> integers for the recv from 0
>
> otherwise we use MPI_INT as a placeholder for the type
>
> (openmpi does not want us to use MPI_DATATYPE_NULL a stupid misinterpretation
> of the standard imho )*/
>
>
>
> displacement[0] = 0;
>
> MPI_Type_create_indexed_block(1, 4, displacement, MPI_INT, type2);
>
> MPI_Type_commit(type2);
>
>
>
> if (rank == 0)
>
> {
>
> for( int i=0; i<size; i++){
>
> displacement[0] = i*4;
>
> /* we create a datatype which is a single block of 4 integers with offset 4
> from the start of sbuffer */
>
> MPI_Type_create_indexed_block(1, 4, displacement, MPI_INT, type + i);
>
> MPI_Type_commit(type+i);
>
> }
>
> for (int i=0; i<16; i++)
>
> sbuffer[i] = i;
>
> }
>
>
>
> for (int i=0; i<size; i++)
>
> printf("rank %d i=%d: scnts %d sdispls %d stype %d rcnts %d rdispls %d
> rtype %d\n", rank, i, scnts[i], sdispls[i], type[i], rcnts[i], rdispls[i],
> type2[i]);
>
>
> MPI_Alltoallw(sbuffer, scnts, sdispls, type, rbuffer, rcnts, rdispls, type2,
> MPI_COMM_WORLD);
>
>
>
> for (int i=0; i<4; i++)
>
> printf("rbuffer[%d] = %d\n", i, rbuffer[i]);
>
> fflush(stdout);
>
>
>
> MPI_Finalize();
>
> return 0;
>
> }
>
>
> --
> Jim Edwards
>
> CESM Software Engineer
> National Center for Atmospheric Research
> Boulder, CO
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