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    <p>Hi Pierre,</p>
    <p>ok, that's a nice trick!  <br>
    </p>
    <p>Thanks for this great hint! :)</p>
    <p>Eric</p>
    <p><br>
    </p>
    <div class="moz-cite-prefix">On 2021-12-14 3:58 p.m., Pierre Jolivet
      wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:31BA04FD-18EF-4E16-92C0-3EA53EF81F1F@joliv.et">
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      Hello Eric,
      <div class="">Why do you want to use a MATIS?</div>
      <div class="">This solution that Barry suggested to me some time
        ago is perfectly functioning: <a
href="https://lists.mcs.anl.gov/pipermail/petsc-dev/2020-January/025491.html"
          class="" moz-do-not-send="true">https://lists.mcs.anl.gov/pipermail/petsc-dev/2020-January/025491.html</a></div>
      <div class="">That’s what I do for optimized (restricted) additive
        Schwarz.</div>
      <div class="">You can see also how to use this “trick” from Barry
        here: <a
href="https://gitlab.com/petsc/petsc/-/commit/ba409789b0c94205af794ad85bdac232504f2b3f#2c7d367ac831f3b0c5fb767c0eb16c1ea7ae7fe0_821_821"
          class="" moz-do-not-send="true">https://gitlab.com/petsc/petsc/-/commit/ba409789b0c94205af794ad85bdac232504f2b3f#2c7d367ac831f3b0c5fb767c0eb16c1ea7ae7fe0_821_821</a> (it’s
        in a WIP branch, and for the fine-level PCASM smoother used in
        PCHPDDM, but at least it’s actual code, in case you do not
        follow what Barry and I are saying in the old thread).</div>
      <div class=""><br class="">
      </div>
      <div class="">Thanks,</div>
      <div class="">Pierre</div>
      <div class=""><br class="">
      </div>
      <div class="">
        <div>
          <blockquote type="cite" class="">
            <div class="">On 14 Dec 2021, at 9:37 PM, Eric Chamberland
              <<a href="mailto:Eric.Chamberland@giref.ulaval.ca"
                class="" moz-do-not-send="true">Eric.Chamberland@giref.ulaval.ca</a>>
              wrote:</div>
            <br class="Apple-interchange-newline">
            <div class="">
              <div class="">Hi,<br class="">
                <br class="">
                We want to use an Additive Schwarz preconditioner (like
                PCASM) combined with overlapping meshes *and* specific
                boundary conditions to local (MATIS) matrices.<br
                  class="">
                <br class="">
                At first sight, MATIS is only supported for BDDC and
                FETI-DP and is not working with PCASM.<br class="">
                <br class="">
                Do we have to write a new PC from scratch to combine the
                use of mesh overlap, MATIS and customized local
                matrices?<br class="">
                <br class="">
                ...or is there any working example we should look at to
                start from? :)<br class="">
                <br class="">
                Thanks a lot!<br class="">
                <br class="">
                Eric<br class="">
                <br class="">
                -- <br class="">
                Eric Chamberland, ing., M. Ing<br class="">
                Professionnel de recherche<br class="">
                GIREF/Université Laval<br class="">
                (418) 656-2131 poste 41 22 42<br class="">
                <br class="">
              </div>
            </div>
          </blockquote>
        </div>
        <br class="">
      </div>
    </blockquote>
    <pre class="moz-signature" cols="72">-- 
Eric Chamberland, ing., M. Ing
Professionnel de recherche
GIREF/Université Laval
(418) 656-2131 poste 41 22 42</pre>
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