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

[CVDV97]

Tony F Chan and Henk A Van Der Vorst. Approximate and incomplete factorizations. In Parallel numerical algorithms, pages 167–202. Springer, 1997.

[Man79]

Thomas A Manteuffel. Shifted incomplete Cholesky factorization. In Sparse Matrix Proceedings 1978, 41–61. SIAM, Philadelphia, PA, 1979.

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

Examples

src/ksp/pc/tutorials/ex2.c

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Index of all PC routines
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Index of all manual pages