> On Mar 10, 2016, at 4:49 PM, Lucas Clemente Vella <[email protected]> wrote: > > What PETSc setting of KSP and PC can be used to solve a linear system with > matrix with null elements on the main diagonal? Such matrices arise on > monolithic methods of solving Navier-Stokes equation. > > I understand it doesn't matter for the KSP method, right?
Correct > > I know that for lots of PC methods it won't work, like Jacobi or SOR. Jacobi just uses a 1 on those entries > Is there any PC that can handle such matrices? > > For PC method that can't handle hollow matrices, are there any kind of > treatment provided by PETSc that can be done to the linear system to ensure > the matrix will have only non-null elements on the main diagonal? Maybe some > kind of matrix reordering? If the nonzeros "naturally" belong on the diagonal, such as with a Stokes problem then PCFIELDSPLIT is exactly the right preconditioner to use. Take a look at its docs especially using the Schur complement style preconditioners which are often very good for Stokes problems. Barry > > -- > Lucas Clemente Vella > [email protected]
