<div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr">Il Ven 13 Apr 2018, 21:27 Sanjay Govindjee <<a href="mailto:s_g@berkeley.edu">s_g@berkeley.edu</a>> ha scritto:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    Wouldn't it make the most sense to do it in a variationally
    consistent manner<br>
    <br>
    rhs_a = int{ N_a delta(x - x_o) }<br>
    <br>
    where x_o is the location of the point source?<br></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto">This is what I meant. However, the current callbacks for residual evaluation in PetscDS do not allow to do it.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div text="#000000" bgcolor="#FFFFFF">
    <br>
    -sanjay<br>
    <br>
    <div class="m_1749010105750101013moz-cite-prefix">On 4/13/18 7:46 PM, Matthew Knepley
      wrote:<br>
    </div>
    <blockquote type="cite">
      <div dir="ltr">
        <div class="gmail_extra">
          <div class="gmail_quote">On Fri, Apr 13, 2018 at 1:40 PM,
            Robert Walker <span dir="ltr"><<a href="mailto:rlwalker@usc.edu" target="_blank" rel="noreferrer">rlwalker@usc.edu</a>></span>
            wrote:<br>
            <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div dir="ltr">
                <div>Hello,</div>
                <div><br>
                </div>
                <div>Is there an example of application of a point
                  source in one of the tutorial  PETScFE style examples?
                  Ideally this would be some point on the interior, and
                  not necessarily on a boundary.</div>
                <div><br>
                  Thanks, and apologies in advance if this is a stupid
                  question,</div>
              </div>
            </blockquote>
            <div><br>
            </div>
            <div>No, good question. You would have to decide what that
              meant in FEM terms. All the internal integrals are done</div>
            <div>with quadrature. So putting the source at a quadrature
              point would work, although its a little difficult to know
              where</div>
            <div>they will be. You could smooth it out a little, and
              check coordinates in the forcing function. Last, you could
              check</div>
            <div>for a "close enough" quadrature point and put it there.
              I think making a slightly extended source is usually best.</div>
            <div><br>
            </div>
            <div>  Thanks,</div>
            <div><br>
            </div>
            <div>     Matt</div>
            <div> </div>
            <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div dir="ltr">
                <div>Robert </div>
                <div><br>
                </div>
                <br clear="all">
                <div>
                  <div class="m_1749010105750101013m_2490555387741070381gmail_signature" data-smartmail="gmail_signature">
                    <div dir="ltr">
                      <div>Robert L. Walker<br>
                      </div>
                      <div>MS Petroleum Engineering</div>
                      <div>Mork Family Department of Chemicals and
                        Materials Sciences<br>
                      </div>
                      <div>University of Southern California<br>
                        ----------------------------------------------<br>
                      </div>
                      <div>Mobile US: +1 (213) - 290 -7101<br>
                      </div>
                      <div>Mobile EU: +34 62 274 66 40<br>
                      </div>
                      <div><a href="mailto:rlwalker@usc.edu" target="_blank" rel="noreferrer">rlwalker@usc.edu</a><br>
                      </div>
                    </div>
                  </div>
                </div>
              </div>
            </blockquote>
          </div>
          <br>
          <br clear="all">
          <div><br>
          </div>
          -- <br>
          <div class="m_1749010105750101013gmail_signature" data-smartmail="gmail_signature">
            <div dir="ltr">
              <div>
                <div dir="ltr">
                  <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><br>
                  </div>
                  <div><a href="http://www.caam.rice.edu/%7Emk51/" target="_blank" rel="noreferrer">https://www.cse.buffalo.edu/~knepley/</a><br>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
    <pre class="m_1749010105750101013moz-signature" cols="72">-- 
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Sanjay Govindjee, PhD, PE
Horace, Dorothy, and Katherine Johnson Professor in Engineering

779 Davis Hall
University of California
Berkeley, CA 94720-1710

Voice:  +1 510 642 6060
FAX:    +1 510 643 5264
<a class="m_1749010105750101013moz-txt-link-abbreviated" href="mailto:s_g@berkeley.edu" target="_blank" rel="noreferrer">s_g@berkeley.edu</a>
<a class="m_1749010105750101013moz-txt-link-freetext" href="http://faculty.ce.berkeley.edu/sanjay" target="_blank" rel="noreferrer">http://faculty.ce.berkeley.edu/sanjay</a>
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Books:  

Engineering Mechanics of Deformable Solids
<a class="m_1749010105750101013moz-txt-link-freetext" href="http://amzn.com/0199651647" target="_blank" rel="noreferrer">http://amzn.com/0199651647</a>

Engineering Mechanics 3 (Dynamics) 2nd Edition
<a class="m_1749010105750101013moz-txt-link-freetext" href="http://amzn.com/3642537111" target="_blank" rel="noreferrer">http://amzn.com/3642537111</a>

Engineering Mechanics 3, Supplementary Problems: Dynamics 
<a class="m_1749010105750101013moz-txt-link-freetext" href="http://www.amzn.com/B00SOXN8JU" target="_blank" rel="noreferrer">http://www.amzn.com/B00SOXN8JU</a>

NSF NHERI SimCenter
<a class="m_1749010105750101013moz-txt-link-freetext" href="https://simcenter.designsafe-ci.org/" target="_blank" rel="noreferrer">https://simcenter.designsafe-ci.org/</a>
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</pre>
  </div>

</blockquote></div></div></div>