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Subject: Re: [OMPI users] Intercommunicators Collective Communciation
From: Spenser Gilliland (spenser_at_[hidden])
Date: 2014-05-09 20:34:02


Thanks for the quick response. I'm having alot of fun learning MPI and
this mailing list has been invaluable.

So, If I do a scatter on an inter communicator will this use all left
process to scatter on all right processes?

Where the left processes define MPI_ROOT and the right processes define
rank.

Thanks,
Spenser
On May 9, 2014 7:22 PM, "Jeff Squyres (jsquyres)" <jsquyres_at_[hidden]>
wrote:

> On May 9, 2014, at 7:56 PM, Spenser Gilliland <spenser_at_[hidden]>
> wrote:
>
> > I'm having some trouble understanding Intercommunicators with
> > Collective Communication. Is there a collective routine to express a
> > transfer from all left process to all right processes? or vice versa?
>
> The intercomm collectives are all basically defined as data movement from
> one group to the other (*and* vice versa), with the obvious exception of
> Barrier, which has no data movement -- just synchronization.
>
> The key to understand is (aside from barrier):
>
> - collectives with intracomms are data movement in the *same* group
> - collectives with intercomms are data movement to the *other* group
>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
>
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