MatILUFactor#

Performs in-place ILU factorization of matrix.

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatILUFactor(Mat mat, IS row, IS col, const MatFactorInfo *info)

Collective

Input Parameters#

mat - the matrix
row - row permutation
col - column permutation
info - structure containing

      levels - number of levels of fill.
      expected fill - as ratio of original fill.
      1 or 0 - indicating force fill on diagonal (improves robustness for matrices
                missing diagonal entries)

Notes#

Most users should employ the KSP interface for linear solvers instead of working directly with matrix algebra routines such as this. See, e.g., KSPCreate().

Probably really in-place only when level of fill is zero, otherwise allocates new space to store factored matrix and deletes previous memory. The preferred approach is to use MatGetFactor(), MatILUFactorSymbolic(), and MatILUFactorNumeric() when not using KSP.