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