Konstantinos Kontzialis <[email protected]> writes: > Thank you for your response. I understand what you have written, but > maybe I'm missing something else . I have > not understood why PETSC is giving me this error. With -snes_mf I get my > code running (however many gmres iterations > are needed and convergence sometimes stalls), but with -snes_mf_operator > I still get the error I posted on the list. What > should I do to overcome it? Am I missing something? Is there anything I > do wrong?
You didn't set an (approximate) Jacobian. If you want to use preconditioning, you either need to build a matrix (possibly with -snes_fd_color) or write your own custom preconditioner.
pgpvwzZMxSiJW.pgp
Description: PGP signature
