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My code performs broadcasting and transmission using bcast and isend simultaneously.
At the receiving end, how can I differentiate between bcast and isend messages? The program is multi-threaded with a receiving end for broadcast messages and received messages. I discover that if I incorrectly accepts an incoming data with ibcast function, the program would crash. How can I best resolved this?
Thanks for helping.
Kind Regards,
Jimmy
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MPI_Bcast is a collective operation. There's no mechanism for it to accept messages from apoint-to-point function like MPI_Isend.Are youdoing something like this?
[cpp]switch(rank) { case 0: MPI_Bcast(buf1, count, type, 0, comm); MPI_Send(buf2, count, type, 1, tag, comm); break; case 1: MPI_Recv(buf2, count, type, 0, tag, comm, status); MPI_Bcast(buf1, count, type, 0, comm); break; }[/cpp]
This code is incorrect because the MPI processes reverse theorder of point-to-point and collective communication. The MPI Forum shows several examples of erroneous collective operations: http://www.mpi-forum.org/docs/mpi-11-html/node86.html#Node86. Can you post some pseudocode illustrating what your program is doing?
Best regards,
Henry
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MPI_Bcast is a collective operation. There's no mechanism for it to accept messages from apoint-to-point function like MPI_Isend.Are youdoing something like this?
[cpp]switch(rank) {
case 0:
MPI_Bcast(buf1, count, type, 0, comm);
MPI_Send(buf2, count, type, 1, tag, comm);
break;
case 1:
MPI_Recv(buf2, count, type, 0, tag, comm, status);
MPI_Bcast(buf1, count, type, 0, comm);
break;
}[/cpp]
This code is incorrect because the MPI processes reverse theorder of point-to-point and collective communication. The MPI Forum shows several examples of erroneous collective operations: http://www.mpi-forum.org/docs/mpi-11-html/node86.html#Node86. Can you post some pseudocode illustrating what your program is doing?
Best regards,
Henry
I wanted to distribute out data as a broadcast to all the slave threads.
However, I require the slave threads to return different types of objects back to the master which perform the broadcast. A simple bcast operation is not sufficient because it does not different the types.
In addition, I may want to perform inter-process communications in between the slave threads. I feel riding on top of MPI infrusturture is the best.
Thanks.
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