On Mon, Mar 23, 2009 at 2:06 PM, Rafael Santos Coelho <span dir="ltr"><<a href="mailto:rafaelsantoscoelho@gmail.com">rafaelsantoscoelho@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Barry,<br><br>sorry if I'm coming off stubborn or something, but I think I'm not following your reasoning.<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
NO.<br>
<br>
If you are using LU to construct a preconditioner then you ARE providing the Jacobian explicitly (as a sparse) matrix. Each time the preconditioner is built this sparse matrix is factored.</blockquote><div><br>What do you mean by "providing the jacobian explicity (as a sparse) matrix"? I thought that there was no explicit jacobian matrix, but only a MATMFFD context.</div>
</div></blockquote><div><br>If there is no matrix, what are you factoring?<br><br> Matt<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="gmail_quote"><div><br>Rafael<br></div></div>
</blockquote></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>