I have a problem here.

My program runs perfectly in MPI version 1.6 series, but it would run into some problem in MPI version 1.4x series. Does MPI 1.4x version have a bug related in MPI_Recv.

The log in Node[1] says that "MPI_Recv in node[1] can not probe tag [11] from source[0]". But in node [0], the log says it Isend message with Tag [11] to dest [1].

int provided;

MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);
if (provided != MPI_THREAD_MULTIPLE)
{
   printf("Sorry, your MPI library does not provide MPI_THREAD_MULTIPLE\n");
   MPI_Abort(MPI_COMM_WORLD, 0);
}

Both of my 1.6x and 1.4x library do not support MPI_THREAD_MULTIPLE. Is this the reason? But why it runs perfect with 1.6x version. 

Thanks very much for your help.

Esaon