# PEXSI

Warning

This section is deprecated and may be removed in a future version.

Support for the PEXSI library is slated for removal.

Parameters for the PEXSI solver to be used within OMEN. [Edit on GitHub]

## Keywords

- NP_SYMB_FACT

- ORDERING

- ROW_ORDERING

- VERBOSITY

## Keyword descriptions

NP_SYMB_FACT: integer = 1

  Usage: NP_SYMB_FACT <integer>

  Number of processors for PARMETIS/PT-SCOTCH. Only used if ORDERING is set to PARALLEL. If 0, the number of processors for PARMETIS/PT-SCOTCH will be set equal to the number of MPI ranks per pole. Note: if more than one processor is used, a segmentation fault may occur in the symbolic factorization phase. [Edit on GitHub]

ORDERING: enum = SEQUENTIAL

  Usage: ORDERING <integer>

  Valid values:

  - `PARALLEL` Parallel ordering using ParMETIS/PT-SCOTCH (PARMETIS option in SuperLU_DIST)

  - `SEQUENTIAL` Sequential ordering using METIS (METIS_AT_PLUS_A option in SuperLU_DIST)

  - `MULTIPLE_MINIMUM_DEGREE` Multiple minimum degree ordering (MMD_AT_PLUS_A option in SuperLU_DIST)

  Ordering strategy for factorization and selected inversion. [Edit on GitHub]

ROW_ORDERING: enum = NOROWPERM

  Usage: ROW_ORDERING <integer>

  Valid values:

  - `NOROWPERM` No row permutation (NOROWPERM option in SuperLU_DIST)

  - `LARGEDIAG` Make diagonal entry larger than off diagonal (LargeDiag option in SuperLU_DIST)

  row permutation strategy for factorization and selected inversion. [Edit on GitHub]

VERBOSITY: enum = SILENT

  Usage: VERBOSITY <integer>

  Valid values:

  - `SILENT`

  - `BASIC`

  - `DETAILED`

  The level of output information. [Edit on GitHub]