Alexander:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Sorry, but I forgot to mention that this is double complex symmetric
matrix. Did you load and treat it like that?</div></blockquote><div>I'm not aware it, thus I used real precision :-( </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div>I'm convinced that matrix A is corrupted or obtained from
an incorrect numerical model.</div>
<div>Also note, your matrix A has size of approx. 60k, which is
too large for sequential direct solver.</div>
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MUMPS takes only several minutes and 6 GB of memory to factorize it.
<br>
This factorization gives residual on the order of 10e-12 and
solution is indeed correct.<br>
<br>
Nevertheless, you're right, there is numerical null-space in this
matrix since it comes <br>
from the discretization of equation that contains curl curl
operator, but practically this <br>
case is not really the worst one. <br><div class="im">
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<div>The error on MatMatSolve() when calling </div>
<div><span style="color:rgb(34,34,34);font-size:13px;font-family:arial,sans-serif">' -pc_type
cholesky -pc_factor_mat_solver_package mumps'</span></div>
<div><span style="color:rgb(34,34,34);font-size:13px;font-family:arial,sans-serif">is
a bug in our petsc-mumps interface. I've pushed a fix to
petsc-3.3</span></div>
<div><a href="http://petsc.cs.iit.edu/petsc/releases/petsc-3.3/rev/8badc49a596e" target="_blank">http://petsc.cs.iit.edu/petsc/releases/petsc-3.3/rev/8badc49a596e</a></div>
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<div>Thanks for your report.</div>
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Thank you for the patch.<span class="HOEnZb"><font color="#888888"><br>
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<pre cols="72">--
Regards,
Alexander</pre>
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