Mudassar,
You can do what you are asking. The receiver uses MPI_ANY_SOURCE for
the source rank value and when you receive a message the
status.MPI_SOURCE will contain the rank of the actual sender not the
receiver's rank. If you are not seeing that then there is a bug somewhere.
--td
On 7/14/2011 9:54 PM, Mudassar Majeed wrote:
Friend,
I can not specify the rank of the sender. Because only
the sender knows to which receiver the message is to be sent. The
receiver does not know from which sender the message will come. I am
trying to do a research work on load balancing in MPI application
where load is redistributed, so in that I require a receiver to
receive a load value from a sender that it does not know. On the other
hand, the sender actually calculates, to which receiver this load
value should be sent. So for this, I want sender to send a message
containing the load to a receiver, but receiver does not know from
which sender the message will come. See, it is like send receiver in
DATAGRAM sockets. The receiver, receives the message on the IP and
port, the message which was directed for it. I want to have same
behavior. But it seems that it is not possible in MPI. Isn't it?
regards,
Mudassar
------------------------------------------------------------------------
*From:* Jeff Squyres <jsquy...@cisco.com>
*To:* Mudassar Majeed <mudassar...@yahoo.com>
*Cc:* Open MPI Users <us...@open-mpi.org>
*Sent:* Friday, July 15, 2011 3:30 AM
*Subject:* Re: [OMPI users] Urgent Question regarding, MPI_ANY_SOURCE.
Right. I thought you were asking about receiving *another* message
from whomever you just received from via ANY_SOURCE.
If you want to receive from a specific sender, you just specify the
rank you want to receive from -- not ANY_SOURCE.
You will always only receive messages that were sent to *you*.
There's no MPI_SEND_TO_ANYONE_WHO_IS_LISTENING functionality, for
example. So your last statement: "But when it captures with ..
MPI_ANY_SOURCE and MPI_ANY_TAG, the receiver will capture any message
(even not targetted for it)" is incorrect.
I guess I still don't understand your question...?
On Jul 14, 2011, at 9:17 PM, Mudassar Majeed wrote:
>
> 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 <jsquy...@cisco.com <mailto:jsquy...@cisco.com>>
> To: Mudassar Majeed <mudassar...@yahoo.com
<mailto:mudassar...@yahoo.com>>; Open MPI Users <us...@open-mpi.org
<mailto:us...@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
> > _______________________________________________
> > users mailing list
> > us...@open-mpi.org <mailto:us...@open-mpi.org>
> > http://www.open-mpi.org/mailman/listinfo.cgi/users
>
>
> --
> Jeff Squyres
> jsquy...@cisco.com <mailto:jsquy...@cisco.com>
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
>
>
>
--
Jeff Squyres
jsquy...@cisco.com <mailto:jsquy...@cisco.com>
For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/
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Oracle
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Developer Tools Engineering | +1.781.442.2631
Oracle *- Performance Technologies*
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Email terry.don...@oracle.com <mailto:terry.don...@oracle.com>
