PCICC#

Incomplete Cholesky factorization preconditioners.

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 is applied (for matrices with block size 1). Call PCFactorSetShiftType(pc,MAT_SHIFT_POSITIVE_DEFINITE); to turn off the shift.

The Manteuffel shift is only implemented for matrices with block size 1

References#

  • **** -*** TONY F. CHAN AND HENK A. VAN DER VORST, Review article: APPROXIMATE AND INCOMPLETE FACTORIZATIONS, Chapter in Parallel Numerical Algorithms, edited by D. Keyes, A. Semah, V. Venkatakrishnan, ICASE/LaRC Interdisciplinary Series in Science and Engineering, Kluwer.

See Also#

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

Examples#

src/ksp/pc/tutorials/ex2.c

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Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages