What if two processes Pi and Pj send message to each other at the same time ?
Will both block in your suggested code ?
if not then I can go for that. BTW, I have tried that before.
regards,
________________________________
From: Lukas Razik <li...@razik.name>
To: Mudassar Majeed <mudassar...@yahoo.com>; "us...@open-mpi.org"
<us...@open-mpi.org>
Sent: Sunday, November 20, 2011 3:22 PM
Subject: Re: [OMPI users] MPI_Irecv, MPI_Wait and MPI_Iprobe
Hello Mudassar!
>Dear people,
> I have a scenario as shown below, please tell me if it
>is possible or not
>
>
>------------------------------------------------------------------
>while(!IsDone)
>{
>
>// some code here
>
>MPI_Irecv( .......... );
>
>// some code here
>
>MPI_Iprobe( ........., &is_there_a_message);
>
>if(is_there_a_message)
> MPI_Wait( ....... );
>
>// move forward ... some other code here....
>
>}
>--------------------------------------------------------------------
>
>My scenario is an
asynchronous communication where some other process may or may not send a
message to this
> process, will MPI_Iprobe find out whether it is necessary to call MPI_Wait()
> or not ?
Sorry, but this conveys no sense to me...
1.You don't need to call MPI_Irecv() before MPI_Iprobe() to get the information
if there's a new message... :)
2. If MPI_Iprobe() returns that there's a message then you don't need to call
MPI_Wait() anymore.
Just receive it by MPI_Recv()... :)
> because if we do not do this the process may start waiting for a message that
> may not come and will block.
Wouldn't this fit?
---
while(!isDone) {
// some code here
MPI_Iprobe(...,there_is_a_message,...); // never blocks
if( there_is_a_message ) {
// doesn't block because there's a message:
MPI_Recv(message,...);
// here you can use your message:
process(message);
}
else
process(other_work); // we have no new message so we do another work
}
---
Here the process will receive the message if there's one.
It won't block if there's no message.
If I haven't understood your problem in the right way - please write more
systematically
- how receiver should react if there's a message (e.g. receive it or what else?)
- how receiver should react if there's no message (e.g. block or continue with
another work?)
Best regards,
Lukas
