On 07/02/2013 05:18 PM, Sufeng Niu wrote:

Thanks a lot, that is most confusing part for me in MPI. I would like to clear this type of problems.

So the blocking begins to send message to itself, but there is no receive posted. Thus, the MPI block it. Am I right here?

Correct.

Thus, I need a nonblocking receive to wait the message here. Can I use blocking receive?

If you use blocking receive, you'll block in the receive; how will you reach the send? -- Pavan -- Pavan Balaji http://www.mcs.anl.gov/~balaji