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Subject: Re: [OMPI users] 3D domain decomposition with MPI
From: Gus Correa (gus_at_[hidden])
Date: 2010-03-10 20:56:55


Eugene Loh wrote:
>
> I don't understand what "waste" or "redundant calculations" you're
> referring to here. Let's say each cell is updated based on itself and
> neighboring values. Each cell has a unique "owner" who computes the
> updated value. That value is shared with neighbors if the cell is near
> the subdomain surface. So, there is a communication cost, but typically
> each new value is computed by only one process.
>

You are right, the overhead is in communication.
Redundant information (on the overlap), not redundant calculation,
is the right way to put it.

Gus Correa