Barry, Thanks a lot. I’d like to use this for a nonlinear variant of a block-gauss-seidel smoother. I would like to use MatInvertBlockDiagonal for speeding up my variant.
I think I can work with this, however I also have the problem to turn my initial matrix into one with a blocksize of 3.When I call: MatConvert(A, MATBAIJ, MAT_INITIAL_MATRIX, Dinverse); Then the matrix Dinverse has blocksize 1 which comes from A. I checked the blocksize before the conversion and it was 3, so it seems to get lost. What is the correct (and elegant) way to turn a matrix into a block matrix? Best Cyrill On 19/09/16 17:18, "Barry Smith" <bsm...@mcs.anl.gov> wrote: > > Cyrill, > > This is very specialized for implementing point block Jacobi; I don't > think it is something you would want to use directly. > > If you do want to use it, it simply returns the inverses of the block > diagonals in column major form. You can then call MatSetValues() with with > each of those blocks into another PETSc matrix. values[i*bs*bs] is the > starting point of each block in the array. > > Barry > >> On Sep 19, 2016, at 4:55 AM, Cyrill Vonplanta <cyrill.von.pla...@usi.ch> >> wrote: >> >> Dear PETSc-Users, >> >> I would like to use the inverted block diagonals of a a matrix. I have seen >> the function MatInvertBlockDiagonal() but I don’t know how to create a >> matrix out of them or an array of block matrizes. >> >> Does anyone have an example on how to use **values to create a PETSc matrix? >> >> Thanks >> Cyrill >
