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<div class="moz-cite-prefix">On 01/12/2015 05:58 PM, Matthew Knepley
wrote:<br>
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cite="mid:CAMYG4G=PiGjaRbiMZ-s2KOm_8Cd85Racv7oVtwz0=8w0JyXgoA@mail.gmail.com"
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<div class="gmail_quote">On Mon, Jan 12, 2015 at 10:57 AM,
Umut Tabak <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:u.tabak@tudelft.nl" target="_blank">u.tabak@tudelft.nl</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">On
01/12/2015 04:29 PM, Matthew Knepley wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
Fieldsplit block preconditioners can be used on this
type of matrix, but success obviously depends on the<br>
analytic character of the operators. In particular, if
we assume that we have great PCs for the diagonal,<br>
then B is the most important variable, and we need to
know what the Schur complement<br>
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Dear Matt,<br>
Thanks, I have a bit of difficult time understanding what
you mean by ¨great PCs¨ for the diagonal? Could you please
rephrase it?<br>
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<div>My impression was that you knew how to solve the
diagonal blocks, but not the full system.</div>
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Thx for the swift reply, well, you mean directly or iteratively? I
looked a bit more but I am not sure if that is possible iteratively
or not, I guess it is not since the character of the blocks on the
diagonal are not well suited to iterative solution techniques. Maybe
I should look into field split documentation once more.<br>
Thx,<br>
Umut<br>
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