On Tue, Apr 13, 2010 at 2:49 PM, <span dir="ltr"><<a href="mailto:tribur@vision.ee.ethz.ch">tribur@vision.ee.ethz.ch</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi,<br>
<br>
using ML I got the error<br>
<br>
"[0]PETSC ERROR: Detected zero pivot in LU factorization"<br>
<br>
As recommended at <a href="http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html" target="_blank">http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html</a>, I tried -pc_factor_shift_nonzero but it doesn't have the desired effect using ML.<br>
<br>
How do I have to formulate the command line option? What does -[level]_pc_factor_shift_nonzero mean? What other parallel preconditioner could I try besides Hypre/Boomeramg or ML?<br></blockquote><div><br></div><div>This means the MG level, like 2. You can see all available options using -help.</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;">
Thanks in advance for your precious help,<br>
<br>
Kathrin<br>
<br>
<br>
</blockquote></div><br><br clear="all"><br>-- <br>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<br>