Originally, my idea is to implement this preconditioner<http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TY8-4MS9JN4-C&_user=686358&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000037498&_version=1&_urlVersion=0&_userid=686358&md5=8ae14f3bace78503c283f15cc0adc533>. As far as I`m concerned, there`s no need to form and store any matrices, only the diagonal elements of the jacobian like I said. This way, I believe I`d have to stick with option #2.
With regard to "The matrix it will receive will be the MFFD that is created by -mat_mf.", what matrix is that actually? The one that is created by the `MatCreateMFFD` routine? "Then you would have to extract the KSP and set your matrix-free PC there." Do the calls to PCSetType and PCShellSetApply plus my own implementation of the `MatrixFreePreconditioner` function do that? Best regards, Rafael -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20081118/b0faff5f/attachment.htm>
