Thanks. Having a robust VBILU is a rather hard work while the new regenerated local blocks may or may not have proper spectral properties and may cause instabilities in iteration process but it would be a problem-dependent issue I think... <br>
<br><div class="gmail_quote">On Fri, Oct 14, 2011 at 5:51 PM, Barry Smith <span dir="ltr"><<a href="mailto:bsmith@mcs.anl.gov">bsmith@mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im"><br>
On Oct 14, 2011, at 9:09 AM, behzad baghapour wrote:<br>
<br>
> So, Am I right with 2 things below?<br>
><br>
> 1- If I set BAIJ for Mat, then the ILU preconditoner automatically recognize to use Block-version of ILU preconditioners? (like VBILUM developed by Saad and coworkers) or I should do more for Block preconditioning?<br>
><br>
> 2- "the block size is the same the matrix block size" means that there is no way to combine the matrix elements to build blocks of possible maximum size like Hash method or something like this?<br>
<br>
</div> No. Though we would love to accept a contribution of a robust dynamic variable block size ILU from users.<br>
<font color="#888888"><br>
Barry<br>
</font><div><div></div><div class="h5"><br>
><br>
> Thanks a lot.<br>
><br>
><br>
><br>
> On Fri, Oct 14, 2011 at 1:50 PM, Matthew Knepley <<a href="mailto:knepley@gmail.com">knepley@gmail.com</a>> wrote:<br>
> On Fri, Oct 14, 2011 at 3:05 AM, behzad baghapour <<a href="mailto:behzad.baghapour@gmail.com">behzad.baghapour@gmail.com</a>> wrote:<br>
> Dear all,<br>
><br>
> How should I efficiently use block-ILU preconditioner in Petsc?<br>
><br>
> I saw in man-page of PCILU:<br>
> "For BAIJ matrices this implements a point block ILU". What exactly it means?<br>
><br>
> That the block size is the same the matrix block size.<br>
><br>
> Matt<br>
><br>
> Regards,<br>
> Behzad<br>
><br>
><br>
><br>
><br>
><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>
><br>
><br>
><br>
> --<br>
> ==================================<br>
> Behzad Baghapour<br>
> Ph.D. Candidate, Mechecanical Engineering<br>
> University of Tehran, Tehran, Iran<br>
> <a href="https://sites.google.com/site/behzadbaghapour" target="_blank">https://sites.google.com/site/behzadbaghapour</a><br>
> Fax: 0098-21-88020741<br>
> ==================================<br>
><br>
<br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>==================================<br>Behzad Baghapour<br>Ph.D. Candidate, Mechecanical Engineering<br>University of Tehran, Tehran, Iran<br><a href="https://sites.google.com/site/behzadbaghapour" target="_blank">https://sites.google.com/site/behzadbaghapour</a><br>
Fax: 0098-21-88020741<br>==================================<br><br>