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<div class="moz-cite-prefix">On 04/23/2015 01:36 PM, Matthew Knepley
wrote:<br>
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<div class="gmail_quote">On Thu, Apr 23, 2015 at 6:28 AM,
anton <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:popov@uni-mainz.de" target="_blank">popov@uni-mainz.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
I'm currently calling DMDAVecGet(Restore)Array on a subset
of processors. It seems to work correctly. So why does
documentation say they are collective on Vec? Are they
really? Unlike VecNorm, for example, it's not really clear
why DMDAVecGetArray should be collective.<br>
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<div>The documentation should be fixed. Its "logically
collective" just like VecGetArray(), and unlike
VecGetArrayRead().</div>
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Am I still on a safe side, or I'm seriously violating
something that's not immediately obvious.<br>
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<div>You are violating something that is not obvious.
GetArray() will increment the status marker on the Vec
since you</div>
<div>could have changed something, but then you will get
inconsistency across processes in this marker, so you
could</div>
<div>make different decisions about whether to recompute
norms, etc. Hard to debug errors.</div>
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OK, thanks Matt, I'll simply add dummy calls on those processes
where I don't need the data.<br>
<br>
Anton<br>
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<div> Thanks,</div>
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<div> Matt</div>
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Thanks,<br>
Anton<br>
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-- <br>
<div class="gmail_signature">What most experimenters take for
granted before they begin their experiments is infinitely
more interesting than any results to which their experiments
lead.<br>
-- Norbert Wiener</div>
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