PCICC#
Incomplete Cholesky factorization preconditioners [CVDV97]
Options Database Keys#
-pc_factor_levels
- number of levels of fill for ICC(k)-pc_factor_in_place - only for ICC(0) with natural ordering, reuses the space of the matrix for its factorization (overwrites original matrix)
-pc_factor_fill
- expected amount of fill in factored matrix compared to original matrix, nfill > 1-pc_factor_mat_ordering_type <natural,nd,1wd,rcm,qmd> - set the row/column ordering of the factored matrix
Notes#
Only implemented for some matrix formats. Not implemented in parallel.
For MATSEQBAIJ matrices this implements a point block ICC.
By default, the Manteuffel shift [Man79] is applied, for matrices with block size 1 only. Call PCFactorSetShiftType(pc,MAT_SHIFT_POSITIVE_DEFINITE);
to turn off the shift.
References#
See Also#
KSP: Linear System Solvers, PCCreate(), PCSetType(), PCType, PC, PCSOR, MatOrderingType, PCILU, PCLU, PCCHOLESKY,
PCFactorSetZeroPivot(), PCFactorSetShiftType(), PCFactorSetShiftAmount(),
PCFactorSetFill(), PCFactorSetMatOrderingType(), PCFactorSetReuseOrdering(),
PCFactorSetLevels()
Level#
beginner
Location#
src/ksp/pc/impls/factor/icc/icc.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages