> (A B) > (C D) > > where A and B are symmetric square matrices and B and C are rectangular. > Obviously I would like to solve this system; though since D is not zero > (such as in, for example, step-20) I can not use the techniques given by > the deal.II tutorial. Jaka szkoda... :-)
You can of course, the Schur complement now just looks like this: D - C A^-1 B (or something like this). > (i) One option is to solve the entire matrix. This is fine for me to > start, but it seems that the PETScWrappers do not allow this type of > matrix (dealii::PETScWrappers::MPI::BlockSparseMatrix) to be passed to the > GMRES solver; for example. Can this be fixed by template argument or > instantiation in the petsc_solver.*? The use of "Blocks" is specific to > deal.II right? All PETSc "sees" is another matrix to play with... No, it sees 4 matrices. But if you don't need the blocks, just use a SparseMatrix instead of a BlockSparseMatrix. > Any guesses which is the way to go? (i) or (ii), both, or even a (iii)?? You should go to the literature and see what the most efficient solver is for this problem. This doesn't depend on the structure of the matrix but the problem this structure results from. The implementation will follow what you want to do, not the other way around ;-) W. -- ------------------------------------------------------------------------- Wolfgang Bangerth email: [email protected] www: http://www.math.tamu.edu/~bangerth/ _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
