<div class="gmail_extra">On Mon, Apr 23, 2012 at 9:23 AM, Dominik Szczerba <span dir="ltr"><<a href="mailto:dominik@itis.ethz.ch" target="_blank">dominik@itis.ethz.ch</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
I am implementing both FormFunction and FormJacobian for the SNES<br>
solver. It seems to start off correctly, with the 2 functions being<br>
called one after another in a loop, and with ||Ax-b|| decreasing about<br>
3 orders of magnitude. But then only the FormFunction is being called<br>
several times, without subsequent calls to FormJacobian and obviously<br>
the residue is not being reduced any further, because there are no<br>
calls to the underlying ksp. If I inspect the solution it looks<br></blockquote><div><br></div><div>This is a line search. If you upgrade to petsc-dev, line search has a lot</div><div>more diagnostics.</div><div><br></div>
<div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
qualitatively "on the way" to the expected one, but the values are not<br>
correct, just as if the iterations were prematurely stopped. What sort<br>
of a problem can such a behavior indicate?<br>
<br>
Regards,<br>
Dominik<br>
</blockquote></div><br><br clear="all"><div><br></div>-- <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>
</div>