Thank you very much. -pc_type jacobi -ksp_type preonly does exactly what I want, even in parallel.
Shi ----- Original Message ---- > From: Hong Zhang <hzhang at mcs.anl.gov> > >Suppose I have a diagonal matrix, what is the best way to invert it in > >PETSc? > > Do I have to install the external packages superlu_dist or mumps? > > I realized that LU or Cholesky decomposition does not work with MPIAIJ > matrices. > > I also know the best way is probably to directly call Vector operations > directly. > > However, I want to keep the same KSPSolve structure so that the same code > > can > be used for non-diagonal MPIAIJ matrices without changing each call to > KSPSolve. > > Thank you very much. > > Without changing your application code, i.e., keep the same KSPSolve > structure, > running it with the option > '-pc_type jacobi' > actually inverts the diagonal matrix, in both sequential and parallel > cases. > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
