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Subject: Re: [OMPI users] MPI_Bcast issue
From: Randolph Pullen (randolph_pullen_at_[hidden])
Date: 2010-08-11 00:10:18


Sure, but broadcasts are faster - less reliable apparently, but much faster for large clusters.  Jeff says that all OpenMPI calls are implemented with point to point B-tree style communications of log N transmissions
So I guess that altoall would be N log N

--- On Wed, 11/8/10, Terry Frankcombe <terry_at_[hidden]> wrote:

From: Terry Frankcombe <terry_at_[hidden]>
Subject: Re: [OMPI users] MPI_Bcast issue
To: "Open MPI Users" <users_at_[hidden]>
Received: Wednesday, 11 August, 2010, 1:57 PM

On Tue, 2010-08-10 at 19:09 -0700, Randolph Pullen wrote:
> Jeff thanks for the clarification,
> What I am trying to do is run N concurrent copies of a 1 to N data
> movement program to affect an N to N solution.

I'm no MPI guru, nor do I completely understand what you are doing, but
isn't this an allgather (or possibly an alltoall)?

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