<div dir="ltr">Yes, I use PETSc <a href="http://2.3.3.">2.3.3.</a> In fact, I didn't use Plapack because Barry told me it didn't work :). I will try it. thanks.<br><br><div class="gmail_quote">On Mon, Sep 22, 2008 at 9:20 PM, Richard Tran Mills <span dir="ltr"><<a href="mailto:rmills@climate.ornl.gov">rmills@climate.ornl.gov</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Matt,<br>
<br>
I use it too. Last time I checked, though, it seemed to be broken in petsc-dev: I could no longer build it using --download-plapack with configure.py. (I think the problem is that no one finished migrating it to the new direct solver interface -- I haven't had time to investigate, though.)<br>
<br>
It was working for me in 2.3.3, though. I assume Yujie is using the release version of PETSc?<br><font color="#888888">
<br>
--Richard</font><div><div class="Wj3C7c"><br>
<br>
Matthew Knepley wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Mon, Sep 22, 2008 at 9:43 PM, Lisandro Dalcin <<a href="mailto:dalcinl@gmail.com" target="_blank">dalcinl@gmail.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Mon, Sep 22, 2008 at 11:03 PM, Yujie <<a href="mailto:recrusader@gmail.com" target="_blank">recrusader@gmail.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Dear Lisandro:<br>
<br>
Barry has tried to establish an interface for Plapack. However, there are<br>
some bugs in Plapack. Therefore, it doesn't work.<br>
</blockquote>
Sorry, I didn't know about those Plapack issues.<br>
</blockquote>
<br>
Neither did I, and seeing as how I use it, this is interesting. Please<br>
please please<br>
report any bugs you find, because I have been using it without problems.<br>
<br>
Matt<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I am wondering if CG in<br>
Petsc can work with parallel dense matrix.<br>
</blockquote>
Of course it works. In fact, any other KSP should work. As Barry said,<br>
The KSP methods are INDEPENDENT of the matrix format, try -pc_type<br>
jacobi as preconditioner.<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
When using the same matrix, which<br>
one is faster, sequential or parallel? thanks.<br>
</blockquote>
For a fixed-size matrix, you should get really good speedups iterating<br>
in parallel. Of course, that would be even better if you can generate<br>
the local rows of the matrix in each processor. If not, communicating<br>
the matrix row from the 'master' to the 'slaves' could be a real<br>
bootleneck (large data to compute at the master while slaves waiting,<br>
large data to scatter from master to slaves), If you cannot avoid<br>
dense matrices, then you should try hard to compute the local rows at<br>
the owning processor.<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Mon, Sep 22, 2008 at 6:51 PM, Lisandro Dalcin <<a href="mailto:dalcinl@gmail.com" target="_blank">dalcinl@gmail.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Well, any iterative solver will actually work, but expect a really<br>
poor scalability :-). I believe (never used dense matrices) that you<br>
could use a direct method (PLAPACK?), but again, be prepared for long<br>
running times if your problem is (even moderately) large.<br>
<br>
On Mon, Sep 22, 2008 at 10:35 PM, Yujie <<a href="mailto:recrusader@gmail.com" target="_blank">recrusader@gmail.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
To my knowledge, PETsc doesn't provide parallel dense matrix-based<br>
solvers,<br>
such as for CG, GMRES and so on. If it is, how to deal with this<br>
problem?<br>
Thanks.<br>
<br>
Regards,<br>
<br>
Yujie<br>
<br>
</blockquote>
<br>
<br>
--<br>
Lisandro Dalcín<br>
---------------<br>
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)<br>
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)<br>
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)<br>
PTLC - Güemes 3450, (3000) Santa Fe, Argentina<br>
Tel/Fax: +54-(0)342-451.1594<br>
<br>
</blockquote>
<br>
</blockquote>
<br>
<br>
--<br>
Lisandro Dalcín<br>
---------------<br>
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)<br>
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)<br>
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)<br>
PTLC - Güemes 3450, (3000) Santa Fe, Argentina<br>
Tel/Fax: +54-(0)342-451.1594<br>
<br>
<br>
</blockquote>
<br>
<br>
<br>
</blockquote>
<br>
</div></div></blockquote></div><br></div>