Thanks, Is there also so easy way to extract those arrays from already created matrix? I created matrix A with function: MatCreateSeqAIJWithArrays(PETSC_COMM_SELF, n_rows, n_rows, r_idx, c_idx, vals, A); Now I would like to extract all tables from matrix A; Dnia 2010-12-12, nie o godzinie 14:30 -0600, Barry Smith pisze: > MatCreateSeqAIJWithArrays