On Fri, Mar 13, 2009 at 4:39 PM, Ravi Kannan <span dir="ltr"><<a href="mailto:rxk@cfdrc.com">rxk@cfdrc.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div>
<div><span><font color="#0000ff" size="2" face="Arial">Hi
Matt</font></span></div>
<div><span><font color="#0000ff" size="2" face="Arial"></font></span> </div>
<div><span><font color="#0000ff" size="2" face="Arial">Are
you suggesting to use MatGetOrdering()?</font></span></div></div></blockquote><div><br>That is one way.<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div><span><font color="#0000ff" size="2" face="Arial"></font></span></div>
<div><span><font color="#0000ff" size="2" face="Arial">Will
it work for parallel matrix?</font></span></div></div></blockquote><div><br>It depends on the particular ordering, but I think most do.<br><br> Matt<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div><span><font color="#0000ff" size="2" face="Arial"></font></span></div>
<div><span><font color="#0000ff" size="2" face="Arial">Thanks.</font></span></div>
<div><span><font color="#0000ff" size="2" face="Arial"></font></span> </div><font color="#888888">
<div><span><font color="#0000ff" size="2" face="Arial">Ravi</font></span></div></font><div><div></div><div class="h5">
<blockquote>
<div dir="ltr" align="left"><font size="2" face="Tahoma">-----Original Message-----<br><b>From:</b>
<a href="mailto:petsc-users-bounces@mcs.anl.gov" target="_blank">petsc-users-bounces@mcs.anl.gov</a> [mailto:<a href="mailto:petsc-users-bounces@mcs.anl.gov" target="_blank">petsc-users-bounces@mcs.anl.gov</a>]<b>On
Behalf Of </b>Matthew Knepley<br><b>Sent:</b> Friday, March 13, 2009 11:34
AM<br><b>To:</b> PETSc users list<br><b>Subject:</b> Re: matrix assembling
time<br><br></font></div>On Fri, Mar 13, 2009 at 12:48 PM, Ravi Kannan <span dir="ltr"><<a href="mailto:rxk@cfdrc.com" target="_blank">rxk@cfdrc.com</a>></span>
wrote:<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi,<br>
This is Ravi Kannan from CFD Research Corporation. One basic question
on<br>the ordering of linear solvers in PETSc: If my A matrix (in AX=B) is
a<br>sparse matrix and the bandwidth of A (i.e. the distance between non
zero<br>elements) is high, does PETSc reorder the matrix/matrix-equations so
as to<br>solve more efficiently. If yes, is there any specific command to do
the<br>above?</blockquote>
<div><br>You can reorder the matrix using the MatOrdering class.<br><br>
Matt<br> </div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>Thanks<br>Ravi<br><br><br><br>-----Original
Message-----<br>From: <a href="mailto:petsc-users-bounces@mcs.anl.gov" target="_blank">petsc-users-bounces@mcs.anl.gov</a><br>[mailto:<a href="mailto:petsc-users-bounces@mcs.anl.gov" target="_blank">petsc-users-bounces@mcs.anl.gov</a>]On
Behalf Of Yixun Liu<br>Sent: Friday, March 06, 2009 12:50 PM<br>To:
PETSC<br>Subject: matrix assembling time<br><br><br>Hi,<br>Using PETSc the
assembling time for a mesh with 6000 vertices is about<br>14 second
parallelized on 4 processors, but another sequential program<br>based on gmm
lib is about 0.6 second. PETSc's solver is much faster than<br>gmm, but I
don't know why its assembling is so slow although I have<br>preallocate an
enough space for the
matrix.<br><br>MatMPIAIJSetPreallocation(sparseMeshMechanicalStiffnessMatrix,
1000,<br>PETSC_NULL, 1000,
PETSC_NULL);<br><br>Yixun<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></blockquote></div></div></div>
</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>