I know this, but when I compare status.MPI_SOURCE with myid, they are different. I guess you need to reconsider my question. The MPI_Recv function seems to capture message from the queue with some search parameters like source, tag etc. So in case the receiver does not know the sender and wants to receive only that message which was sent for this receiver. But when it captures with source as MPI_ANY_SOURCE and MPI_ANY_TAG, the receiver will capture any message (even not targetted for it).

regards,
Mudassar



From: Jeff Squyres <jsquyres@cisco.com>
To: Mudassar Majeed <mudassarm30@yahoo.com>; Open MPI Users <users@open-mpi.org>
Sent: Friday, July 15, 2011 1:58 AM
Subject: Re: [OMPI users] Urgent Question regarding, MPI_ANY_SOURCE.

When you use MPI_ANY_SOURCE in a receive, the rank of the actual sender is passed back to you in the status.MPI_SOURCE.

On Jul 14, 2011, at 7:55 PM, Mudassar Majeed wrote:

> Hello people,
>                        I am trapped in the following problem plz help me. Suppose a process A sends a message to process B. The process B will receive the message with MPI_Recv with MPI_ANY_SOURCE in the source argument. Let say process B does not know that A is the sender. But I want B to receive message from process A (the one who actually sends the message to process B). But if I use MPI_ANY_SOURCE, then any message from any source is captured by process B (let say there are other processes sending messages). Instead of MPI_ANY_SOURCE I cannot use A in the source argument as B does not know about the sender. What should I do in this situation ?
>
> regards,
> Mudassar Majeed
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> users mailing list
> users@open-mpi.org
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