<div class="gmail_quote">On Tue, May 17, 2011 at 20:32, Sylvain Barbot <span dir="ltr"><<a href="mailto:sylbar.vainbot@gmail.com">sylbar.vainbot@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div id=":139">You're right, I should experiment more with assembled matrices before<br>
choosing a solver/preconditioner. Could you be more specific about the<br>
command line options that I could test. I have a version of the code<br>
with assembled sparse matrices (default format). I tried running with<br>
the option -pc_type mg and got the following error:</div></blockquote></div><br><div>You need to set grid information or interpolation operators for this to work. If you have a grid hierarchy, you can set it by following that chapter of the user's manual (which I think you were trying to do with matrix-free operators everywhere). If you use a structured grid, DMMG is quite convenient.</div>
<div><br></div><div>(petsc-dev does not seg-fault on the configuration you gave because the data structure has been improved)</div>