Use -pc_type lu -pc_factor_mat_solver_type umfpack to use this direct solver
Consult UMFPACK documentation for more information about the Control parameters which correspond to the options database keys below.
| -mat_umfpack_ordering | - CHOLMOD, AMD, GIVEN, METIS, BEST, NONE | |
| -mat_umfpack_prl | - UMFPACK print level: Control[UMFPACK_PRL] | |
| -mat_umfpack_strategy <AUTO> | - (choose one of) AUTO UNSYMMETRIC SYMMETRIC 2BY2 | |
| -mat_umfpack_dense_col <alpha_c> | - UMFPACK dense column threshold: Control[UMFPACK_DENSE_COL] | |
| -mat_umfpack_dense_row <0.2> | - Control[UMFPACK_DENSE_ROW] | |
| -mat_umfpack_amd_dense <10> | - Control[UMFPACK_AMD_DENSE] | |
| -mat_umfpack_block_size <bs> | - UMFPACK block size for BLAS-Level 3 calls: Control[UMFPACK_BLOCK_SIZE] | |
| -mat_umfpack_2by2_tolerance <0.01> | - Control[UMFPACK_2BY2_TOLERANCE] | |
| -mat_umfpack_fixq <0> | - Control[UMFPACK_FIXQ] | |
| -mat_umfpack_aggressive <1> | - Control[UMFPACK_AGGRESSIVE] | |
| -mat_umfpack_pivot_tolerance <delta> | - UMFPACK partial pivot tolerance: Control[UMFPACK_PIVOT_TOLERANCE] | |
| -mat_umfpack_sym_pivot_tolerance <0.001> | - Control[UMFPACK_SYM_PIVOT_TOLERANCE] | |
| -mat_umfpack_scale <NONE> | - (choose one of) NONE SUM MAX | |
| -mat_umfpack_alloc_init <delta> | - UMFPACK factorized matrix allocation modifier: Control[UMFPACK_ALLOC_INIT] | |
| -mat_umfpack_droptol <0> | - Control[UMFPACK_DROPTOL] | |
| -mat_umfpack_irstep <maxit> | - UMFPACK maximum number of iterative refinement steps: Control[UMFPACK_IRSTEP] |
Note: UMFPACK is part of SuiteSparse http://faculty.cse.tamu.edu/davis/suitesparse.html