petsc-3.13.6 2020-09-29
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Incomplete Cholesky factorization preconditioners.

Options Database Keys

-pc_factor_levels <k> - 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 <nfill> - 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


Only implemented for some matrix formats. Not implemented in parallel.

For BAIJ matrices this implements a point block ICC.

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

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


1. -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 (for list of available types), PC, PCSOR, MatOrderingType,
PCFactorSetZeroPivot(), PCFactorSetShiftType(), PCFactorSetShiftAmount(), PCFactorSetFill(), PCFactorSetMatOrderingType(), PCFactorSetReuseOrdering(), PCFactorSetLevels()







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