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<div class="moz-cite-prefix">Le 13/01/2014 22:15, Matthew Knepley a
écrit :<br>
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<blockquote
cite="mid:CAMYG4GnAY3Pk_ZW8w_Yjrj8fyaz_4AsbamEWO2T8Jb3CWo+s8w@mail.gmail.com"
type="cite">
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<div class="gmail_quote">On Mon, Jan 13, 2014 at 2:27 PM, Rémi
Lacroix <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:remi.lacroix@inria.fr" target="_blank">remi.lacroix@inria.fr</a>></span>
wrote:<br>
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<div>Le 13/01/2014 19:00, Matthew Knepley a écrit :<br>
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<div class="gmail_quote">On Mon, Jan 13, 2014 at
9:47 AM, Rémi Lacroix <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:remi.lacroix@inria.fr"
target="_blank">remi.lacroix@inria.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">Hello,<br>
<br>
I would like to permute an index set with
another index set, just like you can do for
vectors using VecScatter.<br>
<br>
I have two index sets IS1 and IS2 which share
the same size but have different parallel
layouts. I often need to permute
vectors/matrices using those two index sets
(as in first permute with IS1 then permute the
result with IS2). Since I don't use the
intermediate result, I would like to permute
IS1 with IS2 to get a new index set so that I
can permute directly my vectors/matrices with
it. Is that possible using Petsc?<br>
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<div>We do not have this particular composition
in our interface. However, you could
accomplish this using PetscSF.</div>
<div><br>
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<div> Thanks,
<div><br>
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<div> Matt</div>
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<br>
Thanks for the quick answer.<br>
<br>
So basically I need to have a look at the underlying
mechanism of VecScatter and implement something similar
for IS. How complex would it be in practice?</div>
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<div><br>
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<div>Using the PetscSF interface instead of VecScatter
should not be too hard.</div>
<div><br>
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<div> Matt</div>
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In fact this is quite easier than I expected it to be.<br>
<br>
I have a quick question though. Is it safe to access the row layout
of a matrix using "mat->rmap"? I wasn't able to find a function
to do this. This way I would be able to use "PetscSFSetGraphLayout"
directly.<br>
<br>
Rémi<br>
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