On Tue, Mar 29, 2011 at 09:49, Kontsantinos Kontzialis < ckontzialis at lycos.com> wrote:
> I have another question. I use the Discontinoues Galerkin discretization > for the equations of gas dynamics. I use a matrix free formulation and > that's why I need a very good preconditioner, which I compute it numerically > and untill now it works ok, but it is a bit slow The preconditioner is just > the Jacobian of the system. I wonder if PETSc has a built in capability to > compute its entries. You can use coloring, see snes/examples/tutorials/ex5.c for an example. It is more expensive in 3D and if the stencil is large. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110329/4d235a1f/attachment.htm>
