<br><br><div><span class="gmail_quote">On 3/29/06, <b class="gmail_sendername">Nils Erik Svangård</b> <<a href="mailto:nilserik@gmail.com">nilserik@gmail.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Barry,<br>You wrote this a couple of mails back:<br><br> SNES works by computing p = -approxinv(J)*F(uold) and<br>then does a line search on unew = uold + lambda*p to get the<br>new u. First it uses a test value of 1 for lambda so it
<br>tries to compute F(uold + p). It is possible that uold + p<br>has some "non-physical" values in it.<br><br>Does SNES do the same thing when -snes_mf is used?</blockquote><div><br>
Yes, the line search is independent of the Jacobian approximation.<br>
<br>
Matt<br>
</div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">/nisse<br><br>On 3/20/06, Barry Smith <<a href="mailto:bsmith@mcs.anl.gov">bsmith@mcs.anl.gov
</a>> wrote:<br>><br>> Nisse,<br>><br>> Is there any way you can bundle everything up so you could send<br>> it to me and I could easily compile it and make? This approach to<br>> trying to discover the problem is taking too long.
<br>><br>> Barry<br>
</blockquote></div><br>-- <br>"Failure has a thousand explanations. Success doesn't need one" -- Sir Alec Guiness