On 9/24/06, <b class="gmail_sendername">Gong Ding</b> <<a href="mailto:gdiso@ustc.edu">gdiso@ustc.edu</a>> wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi,<br> I meet some convergince problem with my<br>semiconductor simulation code. I 'd like to check<br>the condition number of Jacobian matrix. How can I<br>do with PETSC?</blockquote><div><br>
The true L_2 condition number would involve a very large<br>
SVD calculation, and thus is rarely computed. We do have<br>
the option:<br>
<br>
-ksp_compute_singularvalues<br>
<br>
which will give you the condition number of the Krylov matrix,<br>
a low-dimensional approximation of your matrix. A very<br>
convenient form of this is:<br>
<br>
-ksp_singmonitor<br>
</div><br>
which includes this information in the KSP monitor.<br>
<br>
Thanks,<br>
<br>
Matt<br>
<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">--<br>USTC Alumni Email System<br>
</blockquote></div>-- <br>"Failure has a thousand explanations. Success doesn't need one" -- Sir Alec Guiness