On Mon, Mar 23, 2009 at 2:06 PM, Rafael Santos Coelho < rafaelsantoscoelho at gmail.com> wrote:
> Barry, > > sorry if I'm coming off stubborn or something, but I think I'm not > following your reasoning. > > NO. >> >> 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. > > > 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. > If there is no matrix, what are you factoring? Matt > > Rafael > -- 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/20090323/06e0f582/attachment.htm>
