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<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff size=2>Hi
Matt</FONT></SPAN></DIV>
<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff size=2>Are
you suggesting to use MatGetOrdering()?</FONT></SPAN></DIV>
<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff size=2>Will
it work for parallel matrix?</FONT></SPAN></DIV>
<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff
size=2>Thanks.</FONT></SPAN></DIV>
<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=218413421-13032009><FONT face=Arial color=#0000ff
size=2>Ravi</FONT></SPAN></DIV>
<BLOCKQUOTE>
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
petsc-users-bounces@mcs.anl.gov [mailto:petsc-users-bounces@mcs.anl.gov]<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">rxk@cfdrc.com</A>></SPAN>
wrote:<BR>
<DIV class=gmail_quote>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">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="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid"><BR>Thanks<BR>Ravi<BR><BR><BR><BR>-----Original
Message-----<BR>From: <A
href="mailto:petsc-users-bounces@mcs.anl.gov">petsc-users-bounces@mcs.anl.gov</A><BR>[mailto:<A
href="mailto:petsc-users-bounces@mcs.anl.gov">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></BODY></HTML>