[mpich-discuss] A bit of clarification on Bcast - Send - Recv

[Rajeev Thakur]

No you cannot match a broadcast with a receive. Note that the text you
mention in Using MPI comes under the section "Common Errors and
Misunderstandings", one of which is "Matching MPI_Bcast with MPI_Recv."

Rajeev

> -----Original Message-----
> From: mpich-discuss-bounces at mcs.anl.gov 
> [mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of Hiatt, Dave M 
> Sent: Wednesday, August 26, 2009 4:19 PM
> To: mpich-discuss at mcs.anl.gov
> Subject: [mpich-discuss] A bit of clarification on Bcast - Send - Recv
> 
> First, I apologize for "if you node", if A node, sorry I 
> think a lot faster than I can type (thank goodness for that).
> 
> My question revolves around a statement on Pg 66 of Using 
> MPI, which led me to believe that I could use MPI::Recv to 
> receive MPI::Bcast messages.  "An MPI::Recv does not have to 
> check whether the message it has just received is part of a 
> broadcast .....".  But in every attempt I have made to us 
> MPI::Recv, it never responds to a MPI::Bcast.  I have assumed 
> that I am making some bonehead mistake, but am now totally 
> frustrated that I have failed to get this to work.  
> MPI::Bcast on the receiving node works fine as a receiver, 
> but MPI::Recv does not for broadcast messages.  I am on 1.0.7 
> of MPICH2 by the way.
> 
> Thanks again
> Dave
> 
> 
> "Premature optimization is the root of all evil" - Donald Knuth
> Dave Hiatt
> Manager, Market Risk Systems Integration
> CitiMortgage, Inc.
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> 
> 
> 
> 
>