It just means that both matrix arguments A and B are the same. What happens if you use this direct solver as a preconditioner? On May 17, 2012 2:23 PM, "Colin McAuliffe" <cjm2176 at columbia.edu> wrote:
> Hello! > > I am solving a coupled multiphysics problem which has several different > units, which leads to a poorly conditioned jacobian. I am using the > following ksp options: > > -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package umfpack > > The results I am getting are not right and I suspect that the conditioning > of the jacobian may be playing a part in that. I would like to improve the > conditioning by using -ksp_diagonal_scale, but adding it does not seem to > help. The documentation for this option says 'this routine is only used if > the matrix and preconditioner matrix are the same thing'. > > Does that mean the command can only be used with no preconditioner? > > http://www.mcs.anl.gov/petsc/**petsc-current/docs/**manualpages/KSP/** > KSPSetDiagonalScale.html<http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSPSetDiagonalScale.html> > > All the best, > > -- > Colin McAuliffe > PhD Candidate > Columbia University > Department of Civil Engineering and Engineering Mechanics > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120517/44d014a6/attachment-0001.htm>
