Dear mpi users and developers,
I am having some trouble with MPI_Allreduce. I am using MinGW (gcc 4.6.2) with OpenMPI 1.6.1. The MPI_Allreduce in c version works fine, but the fortran version failed with error. Here is the simple fortran code to reproduce the error: program main implicit none include 'mpif.h' character * (MPI_MAX_PROCESSOR_NAME) processor_name integer myid, numprocs, namelen, rc, ierr integer, allocatable :: mat1(:, :, :) call MPI_INIT( ierr ) call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr ) call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr ) allocate(mat1(-36:36, -36:36, -36:36)) mat1(:,:,:) = 111 print *, "Going to call MPI_Allreduce." call MPI_Allreduce(MPI_IN_PLACE, mat1(-36, -36, -36), 389017, MPI_INTEGER, MPI_BOR, MPI_COMM_WORLD, ierr) print *, "MPI_Allreduce done!!!" call MPI_FINALIZE(rc) endprogram The command that I used to compile: gfortran Allreduce.f90 -IC:\OpenMPI-win32\include C:\OpenMPI-win32\lib\libmpi_f77.lib The MPI_Allreduce fail. [xxxxxxx:02112] [[17193,0],0]-[[17193,1],0] mca_oob_tcp_msg_recv: readv failed: Unknown error (108). I am not sure why this happens. But I think it is the windows build MPI problem. Since the simple code works on a Linux system with gfortran. Any ideas? I appreciate any response! Yonghui