You could calculate an index incorrectly. Pick the first value that is different.<br>Follow the entire computation by hand.<br><br> Matt<br><br><div class="gmail_quote">On Tue, Apr 21, 2009 at 2:05 PM, (Rebecca) Xuefei YUAN <span dir="ltr"><<a href="mailto:xy2102@columbia.edu">xy2102@columbia.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi,<br>
<br>
I am testing my hand coded jacobian matrix in multi processors with the option "-snes_type test -snes_test_display", and I find that<br>
1) my hand coded jacobian is different from the finite difference jacobian running with 2 processors.<br>
But<br>
2) my jacobian is the same as the finite difference jacobian matrix running with 1 single processor.<br>
Also<br>
3) my hand coded jacobian with 1 processor is the same as my hand coded jacobian with 2 processors.<br>
<br>
Where could be wrong about multiprocessors' jacobian matrix?<br>
<br>
Thanks very much!<br><font color="#888888">
-- <br>
(Rebecca) Xuefei YUAN<br>
Department of Applied Physics and Applied Mathematics<br>
Columbia University<br>
Tel:917-399-8032<br>
<a href="http://www.columbia.edu/%7Exy2102" target="_blank">www.columbia.edu/~xy2102</a><br>
<br>
</font></blockquote></div><br><br clear="all"><br>-- <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>