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    Hello Aswin,<br>
    <br>
    maybe you could give us a bit more information, e.g.<br>
    <br>
    - problem size ? and overlap size<br>
    - seems to be an inexact subdomain solver?<br>
    - what machine did you use? How many cores/nodes ?<br>
    <br>
    Best,<br>
    <br>
    Peter<br>
    <br>
    <div class="moz-cite-prefix">Am 03.01.22 um 11:09 schrieb Aswin vs:<br>
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cite="mid:CADDEfOA-Ab16wuau+YS5jOY3oW8Qynwc1xZdqT1XF9Osnj+fng@mail.gmail.com">
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        <div>Hello, <br>
        </div>
        <div><br>
        </div>
        <div>Can somebody suggest me how to get good scalability while
          using the overlapping solvers in DUNE. I tried the following
          test example in DUNE PDELab, but not getting good scalability.
          <br>
        </div>
        <div>Thank you.<br>
        </div>
        <div><br>
        </div>
        <div>$  mpirun -np 1 ./test-heat-instationary-periodic</div>
        <div>.</div>
        <div>.</div>
        <div>.<br>
        </div>
        STAGE 2 time (to):   1.5000e-02.<br>
        === matrix setup skipped (matrix already allocated)<br>
        === matrix assembly (max) 0.9944 s<br>
        === residual assembly (max) 0.4861 s<br>
        === solving (reduction: 1e-10) === Dune::BiCGSTABSolver<br>
        === rate=0.8397, T=12.57, TIT=0.09524, IT=132<br>
        12.68 s<br>
        ::: timesteps           2 (2)<br>
        ::: nl iterations     565 (565)<br>
        ::: lin iterations    565 (565)<br>
        ::: assemble time    8.0477e+00 (8.0477e+00)<br>
        ::: lin solve time   5.3414e+01 (5.3414e+01)<br>
        <div>---------------------------------------------------------------------------------------<br>
        </div>
        <div>$ mpirun -np 2 ./testheat-instationary-periodic</div>
        <div>.</div>
        <div>.</div>
        <div>.</div>
        <div>STAGE 2 time (to):   1.5000e-02.<br>
          === matrix setup skipped (matrix already allocated)<br>
          === matrix assembly (max) 0.5053 s<br>
          === residual assembly (max) 0.2465 s<br>
          === solving (reduction: 1e-10) === Dune::BiCGSTABSolver<br>
          === rate=0.9268, T=26.95, TIT=0.08895, IT=303<br>
          27.05 s<br>
          ::: timesteps           2 (2)<br>
          ::: nl iterations    1254 (1254)<br>
          ::: lin iterations   1254 (1254)<br>
          ::: assemble time    4.0910e+00 (4.0910e+00)<br>
          ::: lin solve time   1.1201e+02 (1.1201e+02)</div>
        <div>
          <div>---------------------------------------------------------------------------------------<br>
          </div>
          <div>$ mpirun -np 4 ./testheat-instationary-periodic</div>
          <div>.</div>
          <div>.</div>
          <div>.</div>
          <div>STAGE 2 time (to):   1.5000e-02.<br>
            === matrix setup skipped (matrix already allocated)<br>
            === matrix assembly (max) 0.271 s<br>
            === residual assembly (max) 0.1318 s<br>
            === solving (reduction: 1e-10) === Dune::BiCGSTABSolver<br>
            === rate=0.9232, T=26.02, TIT=0.0894, IT=291<br>
            26.11 s<br>
            ::: timesteps           2 (2)<br>
            ::: nl iterations    1249 (1249)<br>
            ::: lin iterations   1249 (1249)<br>
            ::: assemble time    2.1746e+00 (2.1746e+00)<br>
            ::: lin solve time   1.1165e+02 (1.1165e+02)<br>
          </div>
          <div>
            <div>---------------------------------------------------------------------------------------<br>
            </div>
            <div>$ mpirun -np 8 ./testheat-instationary-periodic</div>
            <div>.</div>
            <div>.</div>
            <div>.</div>
            <div>STAGE 2 time (to):   1.5000e-02.<br>
              === matrix setup skipped (matrix already allocated)<br>
              === matrix assembly (max) 0.1772 s<br>
              === residual assembly (max) 0.08259 s<br>
              === solving (reduction: 1e-10) === Dune::BiCGSTABSolver<br>
              === rate=0.9288, T=30.81, TIT=0.09751, IT=316<br>
              30.89 s<br>
              ::: timesteps           2 (2)<br>
              ::: nl iterations    1329 (1329)<br>
              ::: lin iterations   1329 (1329)<br>
              ::: assemble time    1.3485e+00 (1.3485e+00)<br>
              ::: lin solve time   1.2796e+02 (1.2796e+02)</div>
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        <br clear="all">
        <br>
        -- <br>
        <div dir="ltr" class="gmail_signature"
          data-smartmail="gmail_signature">
          <div dir="ltr"><font color="#0b5394">Aswin V.S.</font>
            <div><font color="#6fa8dc">Research Associate-I</font></div>
            <div><font color="#6fa8dc">School of Mathematics</font></div>
            <div><font color="#8e7cc3"><b>Indian Institute of Science
                  Education and Research Thiruvananthapuram</b></font></div>
            <div>
              <div><span style="font-family:arial,sans-serif"><font
                    color="#351c75">Contact: +91 8089542946 / 7994312946</font></span></div>
              <div><span
                  style="font-family:arial,sans-serif;font-size:14px"><b><font
                      color="#351c75">_____________________________________</font></b></span></div>
              <div><span style="font-family:arial,sans-serif"><font
                    color="#666666">"The secret of life is not enjoyment
                    but education through experience."</font></span></div>
              <div><font color="#666666"><span
                    style="font-family:Merriweather,Georgia,serif;font-size:14px">― </span><span
                    style="font-family:Lato,"Helvetica
                    Neue",Helvetica,sans-serif;font-size:14px">Swami
                    Vivekananda</span></font></div>
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      <pre class="moz-quote-pre" wrap="">_______________________________________________
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