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Well I don't bother to much about which PC is use. I just wanted to
look what's possible. One can of course come up with some kind of
augmented Lagrange formulation, but then you end up with a saddle
point problem.<br>
<br>
<div class="moz-cite-prefix">On 19.05.2016 14:41, Matthew Knepley
wrote:<br>
</div>
<blockquote
cite="mid:CAMYG4G=xkxTX1A=-JsQGWAmcoxrBPXt9PwC4E5p7wW7FUKzvBA@mail.gmail.com"
type="cite">
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<div class="gmail_quote">On Thu, May 19, 2016 at 7:39 AM,
Elias Karabelas <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:elias.karabelas@medunigraz.at"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:elias.karabelas@medunigraz.at">elias.karabelas@medunigraz.at</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote">
<div> Ok maybe I should go a little bit more into detail.
I have some stokes problem in a bifurcating Y-tube. Now
I would like to enforce some prescribed flux splits at
the outlets. After some literature research i found a
Nitsche method to do that. And if you consider the
additional billinear forms you end up with some nonlocal
coupling terms at the outlets (which are those vectors I
talked earlier)<br>
</div>
</blockquote>
<div><br>
</div>
<div>Keep the Cc.</div>
<div><br>
</div>
<div>I can see that you might have that formulation, but how
you would incorporate that into AMG, I have no idea.</div>
<div><br>
</div>
<div> Matt</div>
<div> </div>
<blockquote class="gmail_quote">
<div> <br>
<div>On 19.05.2016 14:31, Matthew Knepley wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">On Thu, May 19, 2016 at
7:29 AM, Elias Karabelas <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:elias.karabelas@medunigraz.at"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:elias.karabelas@medunigraz.at">elias.karabelas@medunigraz.at</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote">
<div> maybe something with PCSHELL?</div>
</blockquote>
<div><br>
</div>
<div>No, I mean that I do not understand what
algorithm you might use (apart from the
implementation).</div>
<div><br>
</div>
<div> Matt</div>
<div> </div>
<blockquote class="gmail_quote">
<div>
<div>
<div> <br>
<div>On 19.05.2016 14:28, Matthew
Knepley wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">On Thu,
May 19, 2016 at 2:48 AM, Elias
Karabelas <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:elias.karabelas@medunigraz.at"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:elias.karabelas@medunigraz.at">elias.karabelas@medunigraz.at</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote">Dear
all,<br>
<br>
I have a question about
preconditioned solvers. So, I
have a Sparsematrix, say A,
and now for some reason I
would like to add some
rank-one term u v^T to that
matrix.<br>
As far as I know about Petsc,
I can define the action of
this matrix with MatShell. But
is it possible to adapt the
preconditioner (like a AMG) of
my KSP to handle that kind of
MatShell?<br>
</blockquote>
<div><br>
</div>
<div>I do not know how you would
do that. Its possible other
people have ideas.</div>
<div><br>
</div>
<div> Thanks,</div>
<div><br>
</div>
<div> Matt</div>
<div> </div>
<blockquote class="gmail_quote">
Kind Regards<span><br>
Elias<br>
<br>
-- <br>
Dr Elias Karabelas<br>
<br>
Medical University of Graz<br>
Institute of Biophysics<br>
Harrachgasse 21/IV<br>
8010 Graz, Austria<br>
<br>
Phone: <a
moz-do-not-send="true"
href="tel:%2B43%20316%20380%207759"
value="+433163807759"
target="_blank">+43 316
380 7759</a><br>
Email: <a
moz-do-not-send="true"
href="mailto:elias.karabelas@medunigraz.at"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:elias.karabelas@medunigraz.at">elias.karabelas@medunigraz.at</a></a><br>
Web : <a
moz-do-not-send="true"
href="http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas"
rel="noreferrer"
target="_blank"><a class="moz-txt-link-freetext" href="http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas">http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas</a></a><br>
<br>
</span></blockquote>
</div>
<br>
<br>
<div><br>
</div>
-- <br>
<div>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>
</div>
</div>
</blockquote>
<br>
<pre cols="72">--
Dr Elias Karabelas
Medical University of Graz
Institute of Biophysics
Harrachgasse 21/IV
8010 Graz, Austria
Phone: <a moz-do-not-send="true" href="tel:%2B43%20316%20380%207759" value="+433163807759" target="_blank">+43 316 380 7759</a>
Email: <a moz-do-not-send="true" href="mailto:elias.karabelas@medunigraz.at" target="_blank">elias.karabelas@medunigraz.at</a>
Web : <a moz-do-not-send="true" href="http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas" target="_blank">http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas</a> </pre>
</div>
</div>
</div>
</blockquote>
</div>
<br>
<br>
<span class="HOEnZb">
<div><br>
</div>
-- <br>
<div>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>
</span></div>
<span class="HOEnZb"> </span></div>
<span class="HOEnZb"> </span></blockquote>
<span class="HOEnZb"> <br>
<pre cols="72">--
Dr Elias Karabelas
Medical University of Graz
Institute of Biophysics
Harrachgasse 21/IV
8010 Graz, Austria
Phone: <a moz-do-not-send="true" href="tel:%2B43%20316%20380%207759" value="+433163807759" target="_blank">+43 316 380 7759</a>
Email: <a moz-do-not-send="true" href="mailto:elias.karabelas@medunigraz.at" target="_blank">elias.karabelas@medunigraz.at</a>
Web : <a moz-do-not-send="true" href="http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas" target="_blank">http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas</a> </pre>
</span></div>
</blockquote>
</div>
<br>
<br>
<div><br>
</div>
-- <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>
</div>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Dr Elias Karabelas
Medical University of Graz
Institute of Biophysics
Harrachgasse 21/IV
8010 Graz, Austria
Phone: +43 316 380 7759
Email: <a class="moz-txt-link-abbreviated" href="mailto:elias.karabelas@medunigraz.at">elias.karabelas@medunigraz.at</a>
Web : <a class="moz-txt-link-freetext" href="http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas">http://forschung.medunigraz.at/fodok/staff?name=EliasKarabelas</a> </pre>
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