<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 12 (filtered medium)">
<base href="x-msg://334/">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.apple-style-span
{mso-style-name:apple-style-span;}
span.apple-converted-space
{mso-style-name:apple-converted-space;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-US link=blue vlink=purple style='word-wrap: break-word;
-webkit-nbsp-mode: space;-webkit-line-break: after-white-space'>
<div class=WordSection1>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Matt and Barry - thank you for your replies. While I was
hoping to avoid accessing the matrix directly, I do appreciate the advice.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Have Fun<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> <o:p></o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Daniel "The Plaid Mentat" Crumly<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Daniel.Crumly@colorado.edu<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>--------<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I give you the desert chameleon, whose ability to blend itself
into the background tells you all you need to know about the roots of ecology
and the foundations of a personal identity.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>--Book of Diatribes from the Hayt Chronicle<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>----Herbert, Frank. Children of Dune 28.<o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
petsc-users-bounces@mcs.anl.gov [mailto:petsc-users-bounces@mcs.anl.gov] <b>On
Behalf Of </b>Barry Smith<br>
<b>Sent:</b> Thursday, July 08, 2010 12:20 PM<br>
<b>To:</b> PETSc users list<br>
<b>Subject:</b> Re: [petsc-users] MatMult with factored matrix<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<div>
<p class=MsoNormal>On Jul 8, 2010, at 10:18 AM, Daniel L Crumly wrote:<o:p></o:p></p>
</div>
<p class=MsoNormal><br>
<br>
<o:p></o:p></p>
<div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thank you for the quick reply - I actually do want the
action of the factored matrix (or preconditioner) on a vector. Is there a
recommended workaround?</span><o:p></o:p></p>
</div>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<p class=MsoNormal> If A =approx L*U then applying the
preconditioner involves triangular solves of L and U and use MatSolve() to do
this. If you want to actually apply L*U we don't have code for this, as Matt
mentioned. But note that right, left or split (symmetric) preconditioning do
not need the application of L or U only the triangular solves.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal> If you want to form the product L*U to see how
"far" from A it is we don't have code for that, you could write a new
routine that directly access the data structure and does the product for you,
but since it is not needed for traditional linear solvers we don't provide such
a thing.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal> Barry<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> </span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> </span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Daniel "The Plaid Mentat" Crumly</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><a href="mailto:Daniel.Crumly@colorado.edu">Daniel.Crumly@colorado.edu</a></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>--------</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I give you the desert chameleon, whose ability to blend itself
into the background tells you all you need to know about the roots of ecology
and the foundations of a personal identity.</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>--Book of Diatribes from the Hayt Chronicle</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>----Herbert, Frank. Children of Dune 28.</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> </span><o:p></o:p></p>
</div>
<div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt;
border-width:initial;border-color:initial'>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in;
border-width:initial;border-color:initial'>
<div>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
class=apple-converted-space><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> </span></span><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><a
href="mailto:petsc-users-bounces@mcs.anl.gov">petsc-users-bounces@mcs.anl.gov</a><span
class=apple-converted-space> </span>[mailto:petsc-users-bounces@mcs.anl.gov]<span
class=apple-converted-space> </span><b>On Behalf Of<span
class=apple-converted-space> </span></b>Matthew Knepley<br>
<b>Sent:</b><span class=apple-converted-space> </span>Thursday, July 08,
2010 11:10 AM<br>
<b>To:</b><span class=apple-converted-space> </span>PETSc users list<br>
<b>Subject:</b><span class=apple-converted-space> </span>Re: [petsc-users]
MatMult with factored matrix</span><o:p></o:p></p>
</div>
</div>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>On Thu, Jul 8, 2010 at 7:06 PM, Daniel L Crumly <<a
href="mailto:daniel.crumly@colorado.edu">daniel.crumly@colorado.edu</a>>
wrote:<o:p></o:p></p>
</div>
<div>
<blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;
margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt;
border-width:initial;border-color:initial'>
<div>
<p class=MsoNormal>Hello all -<br>
<br>
Is there a recommended way to multiply a factored matrix by a vector<br>
(effectively MatMult where the matrix is a factored matrix or<br>
preconditioner)? Specifically, I would like to get take the ILU<br>
factorization of a matrix, then multiply a vector by this approximation.<o:p></o:p></p>
</div>
</blockquote>
<div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal>Do you actually want the action, or the action of the
inverse? We only provide<o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal>the action of the inverse<o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><a
href="http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Mat/MatSolve.html">http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Mat/MatSolve.html</a><o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal> Matt<o:p></o:p></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
</div>
<blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;
margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt;
border-width:initial;border-color:initial'>
<p class=MsoNormal style='margin-bottom:12.0pt'>What I currently have is:<br>
<br>
ierr = PCGetType(pc, &pctype);CHKERRQ(ierr);<br>
if (strcmp(pctype, PCILU) == 0 || strcmp(pctype, PCICC) == 0) {<br>
ierr = PCFactorGetMatrix(pc, &M);CHKERRQ(ierr);<br>
ierr = MatMult(M, x, Mx);CHKERRQ(ierr);<br>
}<br>
<br>
which throws the runtime error (I'm currently using PETSc 3.0.0-p8.):<br>
<br>
[0]PETSC ERROR: --------------------- Error Message<br>
------------------------------------<br>
[0]PETSC ERROR: Object is in wrong state!<br>
[0]PETSC ERROR: Not for factored matrix!<br>
[0]PETSC ERROR:<br>
------------------------------------------------------------------------<br>
<br>
Any suggestions are greatly appreciated, thank you.<br>
<br>
Daniel "The Plaid Mentat" Crumly<br>
<a href="mailto:Daniel.Crumly@colorado.edu">Daniel.Crumly@colorado.edu</a><br>
--------<br>
I give you the desert chameleon, whose ability to blend itself into the<br>
background tells you all you need to know about the roots of ecology and the<br>
foundations of a personal identity.<br>
--Book of Diatribes from the Hayt Chronicle<br>
----Herbert, Frank. Children of Dune 28.<br>
<br>
<br>
<o:p></o:p></p>
</blockquote>
</div>
<div>
<p class=MsoNormal><br>
<br clear=all>
<br>
--<span class=apple-converted-space> </span><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<o:p></o:p></p>
</div>
</div>
</div>
</blockquote>
</div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
</div>
</body>
</html>