<html>
<head>
<!-- Template generated by Exclaimer Mail Disclaimers on 09:25:07 Tuesday, 2 August 2016 -->
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css" style="display:none"><!--P{margin-top:0;margin-bottom:0;} --></style>
</head>
<body dir="ltr" style="font-size:12pt;color:#000000;background-color:#FFFFFF;font-family:Calibri,Arial,Helvetica,sans-serif;">
<p></p>
<p>Thanks for your help! Going from individual blocks to a whole<br>
matrix makes perfect sense if the blocks are readily available or<br>
needed as fully functional matrices. Don't change that! Maybe add<br>
the opposite?<br>
<br>
I'm surprised it's broken though: on this mailing list several<br>
petsc developers have stated on several occasions (and not just<br>
to me) things like "you should never have a matnest", "you should<br>
have a mat then change the type at runtime", "snes ex70 is not<br>
the intended use" and so on.<br>
<br>
I fully appreciate the benefit of having a format-independent<br>
assembly and switching mat type from aij to nest depending on the<br>
preconditioner. And given the manual and the statements on this<br>
list, I thought this would be standard practice and therefore<br>
thoroughly tested. But now I get the impression it has never<br>
worked...<br>
<br>
Chris<br>
<br>
<br>
> From: Matthew Knepley <knepley@gmail.com><br>
> Sent: Tuesday, August 02, 2016 12:28 AM<br>
> To: Klaij, Christiaan<br>
> Cc: petsc-users@mcs.anl.gov; Jed Brown<br>
> Subject: Re: [petsc-users] block matrix without MatCreateNest<br>
> <br>
> On Mon, Aug 1, 2016 at 9:36 AM, Klaij, Christiaan <C.Klaij@marin.nl> wrote:<br>
> <br>
> Matt,<br>
> <br>
> <br>
> 1) great!<br>
> <br>
> <br>
> 2) ??? that's precisely why I paste the output of "cat mattry.F90" in the emails, so you have a small example that produces the errors I mention. Now I'm also attaching it to this email.<br>
> <br>
> Okay, I have gone through it. You are correct that it is completely broken.<br>
> <br>
> The way that MatNest currently works is that it trys to use L2G mappings from individual blocks<br>
> and then builds a composite L2G map for the whole matrix. This is obviously incompatible with<br>
> the primary use case, and should be changed to break up the full L2G into one for each block.<br>
> <br>
> Jed, can you fix this? I am not sure I know enough about how Nest works.<br>
> <br>
> Matt<br>
> <br>
> Thanks,<br>
> <br>
> Chris</p>
<p><br>
</p>
<br>
<font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">dr. ir.</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">
</font><font style="font-family: Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">Christiaan</font><font style="font-family: Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">Klaij</font><font size="3" face="Segoe UI"></font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;"> |
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">CFD Researcher</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;"> |
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;font-weight:bold;">Research & Development</font><br>
<font style="font-family:Verdana;font-size:9pt;color:#7D7D7D;font-weight:bold;">MARIN</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;"> | T
</font><font style="font-family:Verdana;font-size:8pt;color:#7D7D7D;">+31 317 49 33 44</font><font color="#7d7d7d" size="2" face="Segoe UI"></font><font style="font-family:Verdana;font-size:8pt;"> |
</font><span style="font-family:Verdana;font-size:8pt;"><a href="mailto:C.Klaij@marin.nl" title="" target="" style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana; font-size:8pt;">C.Klaij@marin.nl</span></a></span><font color="#7d7d7d" size="2" face="Segoe UI"></font><font style="font-family:Verdana;font-size:8pt;"> |
</font><span style="font-family:Verdana;font-size:8pt;"><a href="http://www.marin.nl" title="" target="" style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana; font-size:8pt;">www.marin.nl</span></a></span><br>
<br>
<a href="https://www.linkedin.com/company/marin" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:imagece5c8d.PNG@c5f6c9ea.4f8a1d1f" alt="LinkedIn"></a> <a href="http://www.youtube.com/marinmultimedia" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:imagec9421a.PNG@0c0b4680.4a93d77d" alt="YouTube"></a> <a href="https://twitter.com/MARIN_nieuws" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:image257f89.PNG@dab3e011.4e89447d" alt="Twitter"></a> <a href="https://www.facebook.com/marin.wageningen" target=""><img width="16" height="16" style="border: 0px Solid ; " src="cid:imagec2e203.PNG@3252c9d9.448edcc6" alt="Facebook"></a><br>
<font style="FONT-FAMILY: Verdana; FONT-SIZE: 8pt" color="#7d7d7d" size="2" face="Verdana">MARIN news:
<font style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana;font-size:8pt;"><a href="http://www.marin.nl/web/News/News-items/Ship-design-in-EU-project-Holiship.htm" title="" target="" style="font-family:Verdana;font-size:8pt;"><span style="font-family:Verdana; font-size:8pt;">Ship
design in EU project Holiship</span></a></span></font></font>
<p></p>
<p></EXCLAIMER:ORIGINAL_BODY_AFTER></p>
</EXCLAIMER:TEXT_ONLY></EXCLAIMER:AD></EXCLAIMER:AD>
</body>
</html>