<div class="gmail_quote">On Fri, Nov 11, 2011 at 05:52, Konstantinos Kontzialis <span dir="ltr"><<a href="mailto:ckontzialis@lycos.com">ckontzialis@lycos.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
However as you may see the convergence is very very slow? Any
suggestions?</blockquote></div><br><div>The linear solve is still diverging, so it's meaningless what the SNES residual is. You need to monitor the true residual and find out why the linear solve is failing. As I told you many times, you need to check the scaling of the equations. It appears that you are seeing noise from rounding error in finite differencing. This usually means that you need to rescale your equations (choose different units). I also asked several times about ordering of unknowns, but you never replied to that part either. Please go through the items in this FAQ:</div>
<div><br></div><div><a href="http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#kspdiverged">http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#kspdiverged</a></div>