<div dir="ltr">Hi all,<div><br></div><div>Hong--looking at your link, there may be no special algorithm for Hermitian matrices in MUMPS, but that doesn't mean it can't solve them like it would any matrix. Furthermore it appears that Cholesky of complex matrices is supported from this link: <a href="https://www.mcs.anl.gov/petsc/documentation/linearsolvertable.html">https://www.mcs.anl.gov/petsc/documentation/linearsolvertable.html</a></div><div><br></div><div>So do you or anyone have any idea why I get incorrect eigenvalues?</div><div><br></div><div>Thanks,<br></div><div>Greg</div></div><br><div class="gmail_quote"><div dir="ltr">On Thu, Sep 21, 2017 at 5:51 PM Greg Meyer <<a href="mailto:gregory.meyer@gmail.com">gregory.meyer@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Ok, thanks. It seems that PETSc clearly should throw an error in this case instead of just giving incorrect answers? I am surprised that it does not throw an error...</div><br><div class="gmail_quote"><div dir="ltr">On Thu, Sep 21, 2017 at 5:24 PM Hong <<a href="mailto:hzhang@mcs.anl.gov" target="_blank">hzhang@mcs.anl.gov</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">Greg :<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Yes, they are Hermitian.</div></blockquote><div> </div><div>PETSc does not support Cholesky factorization for Hermitian.</div><div>It seems mumps does not support Hermitian either</div><div><a href="https://lists.mcs.anl.gov/mailman/htdig/petsc-users/2015-November/027541.html" target="_blank">https://lists.mcs.anl.gov/mailman/htdig/petsc-users/2015-November/027541.html</a><br></div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div><br></div><div>Hong</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="m_3744362379546753899m_6675289382118951847gmail-HOEnZb"><div class="m_3744362379546753899m_6675289382118951847gmail-h5"><br><div class="gmail_quote"><div dir="ltr">On Thu, Sep 21, 2017 at 3:43 PM Hong <<a href="mailto:hzhang@mcs.anl.gov" target="_blank">hzhang@mcs.anl.gov</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">Greg:</div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">OK, the difference is whether LU or Cholesky factorization is used. But I would hope that neither one should give incorrect eigenvalues, and when I run with the latter it does!</div></blockquote></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>Are your matrices symmetric/Hermitian?</div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>Hong</div></div></div></div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="m_3744362379546753899m_6675289382118951847gmail-m_-3963994936178457407m_-8487120594974510340HOEnZb"><div class="m_3744362379546753899m_6675289382118951847gmail-m_-3963994936178457407m_-8487120594974510340h5"><br><div class="gmail_quote"><div dir="ltr">On Thu, Sep 21, 2017 at 2:05 PM Hong <<a href="mailto:hzhang@mcs.anl.gov" target="_blank">hzhang@mcs.anl.gov</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">Gregory :</div><div class="gmail_quote">Use '-eps_view' for both runs to check the algorithms being used. </div><div class="gmail_quote">Hong</div><div class="gmail_quote"><br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi all,<div><br></div><div>I'm using shift-invert with EPS to solve for eigenvalues. I find that if I do only</div><div><br></div><div><font face="monospace">...</font></div><div><font face="monospace"> ierr = EPSGetST(eps,&st);CHKERRQ(ierr);</font></div><div><font face="monospace"> ierr = STSetType(st,STSINVERT);CHKERRQ(ierr);</font></div><div><font face="monospace">...</font></div><div><font face="monospace"><br></font></div><div>in my code I get correct eigenvalues. But if I do </div><div><font face="monospace"><br></font></div><div><font face="monospace">...</font></div><div><div style="font-family:monospace"> ierr = EPSGetST(eps,&st);CHKERRQ(ierr);</div><div style="font-family:monospace"> ierr = STSetType(st,STSINVERT);CHKERRQ(ierr);</div><div style="font-family:monospace"> ierr = STGetKSP(st,&ksp);CHKERRQ(ierr);</div><div style="font-family:monospace"> ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);</div><div style="font-family:monospace"> ierr = KSPSetType(ksp,KSPPREONLY);CHKERRQ(ierr);</div><div style="font-family:monospace"> ierr = PCSetType(pc,PCCHOLESKY);CHKERRQ(ierr);</div><div style="font-family:monospace">...</div><div><br></div><div>the eigenvalues found by EPS are completely wrong! Somehow I thought I was supposed to do the latter, from the examples etc, but I guess that was not correct? I attach the full piece of test code and a test matrix.</div><div><br></div><div>Best,</div><div>Greg</div></div></div>
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