Hello everybody. We would like to setup an algebraic multi-grid block preconditioner and I would like to be able to define custom blocks of variable sizes. Reading the documentation, it seems that this can be achieved using the "PCGAMG" preconditioner and defining the blocks with the function "MatSetVariableBlockSizes". Is this correct? Are the variable blocks exploited by PCGAMG algorithms? We suppose this PC structure is already exploited in PCVPBJACOBI. Are the different options like PCHYPRE (setting "-pc_hypre_type" to "boomeramg") suitable for AMG preconditioner with variable size blocks? If none of the above solutions are available, could anyone suggest any other strategy in order to get a preconditioner like this using PETSc? Any help is much appreciated. Thanks.
Best regards, Marco Cisternino
