You could calculate an index incorrectly. Pick the first value that is different. Follow the entire computation by hand.
Matt On Tue, Apr 21, 2009 at 2:05 PM, (Rebecca) Xuefei YUAN <xy2102 at columbia.edu>wrote: > Hi, > > I am testing my hand coded jacobian matrix in multi processors with the > option "-snes_type test -snes_test_display", and I find that > 1) my hand coded jacobian is different from the finite difference jacobian > running with 2 processors. > But > 2) my jacobian is the same as the finite difference jacobian matrix running > with 1 single processor. > Also > 3) my hand coded jacobian with 1 processor is the same as my hand coded > jacobian with 2 processors. > > Where could be wrong about multiprocessors' jacobian matrix? > > Thanks very much! > -- > (Rebecca) Xuefei YUAN > Department of Applied Physics and Applied Mathematics > Columbia University > Tel:917-399-8032 > www.columbia.edu/~xy2102 <http://www.columbia.edu/%7Exy2102> > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20090421/b933741e/attachment.htm>
