<div dir="ltr"><div>Hi Adam, </div><div>Thanks for your reply.</div><div><br></div><div><br></div><div> 0.100000E-09 p021 DIVERGENCE</div><div>  0.100000E-09 p022 HELMHOLTZ</div><div>  0.100000E-09 p024 TOLREL</div><div>  0.100000E-04 p025 TOLABS</div><div>  1.00000E-06 p113 : ARNOLDI: arpack tolerance<br></div><div>Number of mesh element for entire domain is 1200.</div><div>

<span style="font-size:12.8px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><span> T</span>he resolution in cylinder vicinity</span>

<br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jul 12, 2018 at 9:41 PM,  <span dir="ltr"><<a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    <div>Hi;<br>
      What is your tolerance for eigenvalue convergence? I'm unable to
      answer your question directly, as there can be number of problems.
      One of the obvious ones could be mesh resolution. You have pretty
      big mesh. What is the resolution in cylinder vicinity? What is the
      polynomial order? You have number of eigenvalues converged to
      machine accuracy and a few of the order 10**-4 in between. Those
      could be some spurious modes related to insufficient resolution. 
      What is your Reynolds number?<br>
      Regards<br>
      Adam<div><div class="h5"><br>
      <br>
      On 12/07/18 10:07, <a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.<wbr>gov</a> wrote:<br>
    </div></div></div>
    <blockquote type="cite"><div><div class="h5">
      <div dir="ltr">
        <div style="font-size:12.8px">Hi
          Neks</div>
        <div style="font-size:12.8px"><br>
        </div>
        <div style="font-size:12.8px">   
          I am running a 3D simulation for a flow over a cylinder. My
          domain size for simulation is 100Dx100D. where D is the
          diameter of a cylinder. We have obtained the base flow through
          SFD. The base flow is used to calculate the stability analysis
          through NEK5000 with the ARPACK library (Implemented by A. 
          Peplinski).</div>
        <div style="font-size:12.8px"><br>
        </div>
        <div style="font-size:12.8px">we
          have used the following parameters.....</div>
        <div style="font-size:12.8px"><br>
        </div>
        <div>
          <div style="font-size:12.8px">  90.0000     p111 : ARNOLDI:
            size of Krylov space</div>
          <div style="font-size:12.8px">   30.0000     p112 : ARNOLDI:
            number of eigenvectors</div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px">We have run the Arnoldi with
            restart but we are not able to get the output file
            (eigenvalues.txt and egvext_cyl0.f0..) even after almost 20
            restarts.</div>
          <div style="font-size:12.8px">Also, we tried to run with
            increasing the <span style="background-color:rgb(255,255,255);float:none;display:inline">size
              of Krylov space but the eigenvalues are not converging.</span></div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px">The log file shows no changes in
            converged ritz values after around 20-22 values.</div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px">The part of the log file is
            shown below...........</div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px">Kindly,  help me out and let me
            know where I am going wrong.....</div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px">Alok Mishra</div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px"><br>
          </div>
          <div style="font-size:12.8px">------------------------------<wbr>------------------------------<wbr>------------------------------<wbr>---------------------</div>
          <div style="font-size:12.8px"><br>
          </div>
          <div>
            <div><span style="font-size:12.8px">ARNOLDI: after  520
                stepper phase</span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"> _naup2: Corresponding
                B-norm of the residual</span></div>
            <div><span style="font-size:12.8px"> -----------------------------<wbr>---------------</span></div>
            <div><span style="font-size:12.8px">    1 -    1: 
                 6.623D-01</span></div>
            <div><span style="font-size:12.8px">  </span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"> _naup2: no. of
                "converged" Ritz values at this iter.</span></div>
            <div><span style="font-size:12.8px"> -----------------------------<wbr>-----------------------</span></div>
            <div><span style="font-size:12.8px">    1 -    1:    22</span></div>
            <div><span style="font-size:12.8px">  </span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"> _naup2: NEV and NP are</span></div>
            <div><span style="font-size:12.8px"> ----------------------</span></div>
            <div><span style="font-size:12.8px">    1 -    2:    52 
                 128</span></div>
            <div><span style="font-size:12.8px">  </span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"> _naup2: "wanted" Ritz
                values -- real part</span></div>
            <div><span style="font-size:12.8px"> -----------------------------<wbr>------------</span></div>
            <div><span style="font-size:12.8px">    1 -    5: 
                 9.905D-01   9.905D-01   9.854D-01   9.854D-01 
                 9.855D-01</span></div>
            <div><span style="font-size:12.8px">    6 -   10: 
                 9.855D-01   9.897D-01   9.897D-01   9.924D-01 
                 9.930D-01</span></div>
            <div><span style="font-size:12.8px">   11 -   15: 
                 9.930D-01   9.905D-01   9.905D-01   9.943D-01 
                 9.943D-01</span></div>
            <div><span style="font-size:12.8px">   16 -   20: 
                 9.938D-01   9.938D-01   9.948D-01   9.948D-01 
                 9.949D-01</span></div>
            <div><span style="font-size:12.8px">   21 -   25: 
                 9.949D-01   9.951D-01   9.958D-01   9.960D-01 
                 9.962D-01</span></div>
            <div><span style="font-size:12.8px">   26 -   30: 
                 9.962D-01   9.966D-01   9.970D-01   9.970D-01 
                 9.969D-01</span></div>
            <div><span style="font-size:12.8px">   31 -   35: 
                 9.969D-01   9.973D-01   9.974D-01   9.975D-01 
                 9.976D-01</span></div>
            <div><span style="font-size:12.8px">   36 -   40: 
                 9.976D-01   9.971D-01   9.971D-01   9.978D-01 
                 9.979D-01</span></div>
            <div><span style="font-size:12.8px">   41 -   45: 
                 9.979D-01   9.982D-01   9.982D-01   1.000D+00 
                 9.908D-01</span></div>
            <div><span style="font-size:12.8px">   46 -   50: 
                 9.908D-01   1.004D+00   1.004D+00   1.005D+00 
                 1.005D+00</span></div>
            <div><span style="font-size:12.8px">   51 -   52: 
                 1.006D+00   1.006D+00</span></div>
            <div><span style="font-size:12.8px">  </span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"> _naup2: "wanted" Ritz
                values -- imag part</span></div>
            <div><span style="font-size:12.8px"> -----------------------------<wbr>------------</span></div>
            <div><span style="font-size:12.8px">    1 -    5: 
                 5.038D-02  -5.038D-02  -1.127D-01   1.127D-01 
                -1.119D-01</span></div>
            <div><span style="font-size:12.8px">    6 -   10: 
                 1.119D-01   6.954D-02  -6.954D-02   0.000D+00 
                 3.705D-03</span></div>
            <div><span style="font-size:12.8px">   11 -   15: 
                -3.705D-03  -7.103D-02   7.103D-02  -9.233D-04 
                 9.233D-04</span></div>
            <div><span style="font-size:12.8px">   16 -   20: 
                 4.345D-02  -4.345D-02   6.799D-04  -6.799D-04 
                -1.821D-02</span></div>
            <div><span style="font-size:12.8px">   21 -   25: 
                 1.821D-02   0.000D+00   0.000D+00   0.000D+00 
                -2.047D-03</span></div>
            <div><span style="font-size:12.8px">   26 -   30: 
                 2.047D-03   0.000D+00   7.200D-05  -7.200D-05 
                 2.386D-02</span></div>
            <div><span style="font-size:12.8px">   31 -   35: 
                -2.386D-02   0.000D+00   0.000D+00   0.000D+00 
                -1.140D-04</span></div>
            <div><span style="font-size:12.8px">   36 -   40: 
                 1.140D-04   3.125D-02  -3.125D-02   0.000D+00 
                -1.248D-04</span></div>
            <div><span style="font-size:12.8px">   41 -   45: 
                 1.248D-04  -1.673D-03   1.673D-03   0.000D+00 
                -1.508D-01</span></div>
            <div><span style="font-size:12.8px">   46 -   50: 
                 1.508D-01  -1.863D-02   1.863D-02  -2.109D-02 
                 2.109D-02</span></div>
            <div><span style="font-size:12.8px">   51 -   52: 
                -1.152D-02   1.152D-02</span></div>
            <div><span style="font-size:12.8px">  </span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"> _naup2: Ritz estimates
                of the "wanted" values </span></div>
            <div><span style="font-size:12.8px"> -----------------------------<wbr>-----------------</span></div>
            <div><span style="font-size:12.8px">    1 -    5: 
                 3.315D-02   3.315D-02   3.244D-05   3.244D-05 
                 7.035D-05</span></div>
            <div><span style="font-size:12.8px">    6 -   10: 
                 7.035D-05   6.072D-11   6.072D-11   1.314D-02 
                 2.772D-06</span></div>
            <div><span style="font-size:12.8px">   11 -   15: 
                 2.772D-06   6.796D-15   6.796D-15   9.719D-04 
                 9.719D-04</span></div>
            <div><span style="font-size:12.8px">   16 -   20: 
                 7.467D-17   7.467D-17   5.506D-04   5.506D-04 
                 2.437D-16</span></div>
            <div><span style="font-size:12.8px">   21 -   25: 
                 2.437D-16   2.977D-03   7.238D-04   6.054D-04 
                 3.914D-11</span></div>
            <div><span style="font-size:12.8px">   26 -   30: 
                 3.914D-11   1.827D-04   1.138D-04   1.138D-04 
                 1.048D-16</span></div>
            <div><span style="font-size:12.8px">   31 -   35: 
                 1.048D-16   1.198D-04   6.358D-05   3.013D-05 
                 3.490D-07</span></div>
            <div><span style="font-size:12.8px">   36 -   40: 
                 3.490D-07   9.960D-18   9.960D-18   1.340D-07 
                 2.518D-10</span></div>
            <div><span style="font-size:12.8px">   41 -   45: 
                 2.518D-10   1.827D-16   1.827D-16   1.781D-16 
                 7.278D-17</span></div>
            <div><span style="font-size:12.8px">   46 -   50: 
                 7.278D-17   0.000D+00   0.000D+00   0.000D+00 
                 0.000D+00</span></div>
            <div><span style="font-size:12.8px">   51 -   52: 
                 0.000D+00   0.000D+00</span></div>
            <div><span style="font-size:12.8px">  </span></div>
            <div><span style="font-size:12.8px"> Reached max iteration
                number; settingido=-2 for checkpointing.</span></div>
            <div><span style="font-size:12.8px"> ARNOLDI: </span></div>
            <div><span style="font-size:12.8px"> IDOARP  =           -2</span></div>
            <div><span style="font-size:12.8px"> Writing checkpoint</span></div>
            <div><span style="font-size:12.8px">       0      40 OPEN:
                ARPm11800.f00002</span></div>
            <div><span style="font-size:12.8px">       0      40 OPEN:
                ARVm11800.f00002</span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px">       40  2.0000E-01
                done :: Write checkpoint</span></div>
            <div><span style="font-size:12.8px">                       
                      file size =     621.E+00MB</span></div>
            <div><span style="font-size:12.8px">                       
                      avg data-throughput =   624.1MB/s</span></div>
            <div><span style="font-size:12.8px">                       
                      io-nodes =     1</span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"> </span></div>
            <div><span style="font-size:12.8px"> ARNOLDI: finalize</span></div>
            <div><span style="font-size:12.8px">    Number of stepper
                cycles            520</span></div>
            <div><span style="font-size:12.8px">    Time spent in
                ARNOLDI         60.3302609920502     </span></div>
            <div><span style="font-size:12.8px">    Average stepper
                phase time    10.9141681075096     </span></div>
            <div><span style="font-size:12.8px"> call outfld: ifpsco: F</span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px">       40  2.0000E-01
                Write checkpoint:</span></div>
            <div><span style="font-size:12.8px">       0      40 OPEN:
                m11800.f00001</span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px">       40  2.0000E-01
                done :: Write checkpoint</span></div>
            <div><span style="font-size:12.8px">                       
                      file size =      4.0    MB</span></div>
            <div><span style="font-size:12.8px">                       
                      avg data-throughput =   303.2MB/s</span></div>
            <div><span style="font-size:12.8px">                       
                      io-nodes =     1</span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px"><br>
              </span></div>
            <div><span style="font-size:12.8px">end of time-step loop</span></div>
            <div style="font-size:12.8px"><br>
            </div>
          </div>
          <div style="font-size:12.8px"> </div>
        </div>
        <div><br>
        </div>
        <div>
          <div dir="ltr">
            <div dir="ltr">
              <div><br>
              </div>
            </div>
          </div>
        </div>
      </div>
      <br>
      <fieldset></fieldset>
      <br>
      </div></div><span class=""><pre>______________________________<wbr>_________________
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</pre>
    </span></blockquote>
    <p><br>
    </p>
  </div>

<br>______________________________<wbr>_________________<br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr">Alok Mishra<div>Research Scholar </div><div>Computational Propulsion Lab </div><div>Aerospace Department IIT Kanpur</div><div>+91-8795844555</div></div></div></div></div>
</div>