| -pc_factor_levels <k> | - number of levels of fill for ILU(k)
|
| -pc_factor_in_place | - only for ILU(0) with natural ordering, reuses the space of the matrix for
its factorization (overwrites original matrix)
|
| -pc_factor_diagonal_fill | - fill in a zero diagonal even if levels of fill indicate it wouldn't be fill
|
| -pc_factor_reuse_ordering | - reuse ordering of factorized matrix from previous factorization
|
| -pc_factor_fill <nfill> | - expected amount of fill in factored matrix compared to original matrix, nfill > 1
|
| -pc_factor_nonzeros_along_diagonal | - reorder the matrix before factorization to remove zeros from the diagonal,
this decreases the chance of getting a zero pivot
|
| -pc_factor_mat_ordering_type <natural,nd,1wd,rcm,qmd> | - set the row/column ordering of the factored matrix
|
| -pc_factor_pivot_in_blocks | - for block ILU(k) factorization, i.e. with BAIJ matrices with block size larger
than 1 the diagonal blocks are factored with partial pivoting (this increases the
stability of the ILU factorization
|
Notes: Only implemented for some matrix formats. (for parallel see PCHYPRE for hypre's ILU)
For BAIJ matrices this implements a point block ILU
References
T. Dupont, R. Kendall, and H. Rachford. An approximate factorization procedure for solving
self-adjoint elliptic difference equations. SIAM J. Numer. Anal., 5:559--573, 1968.
T.A. Oliphant. An implicit numerical method for solving two-dimensional time-dependent dif-
fusion problems. Quart. Appl. Math., 19:221--229, 1961.
Review article: APPROXIMATE AND INCOMPLETE FACTORIZATIONS, TONY F. CHAN AND HENK A. VAN DER VORST
http://igitur-archive.library.uu.nl/math/2001-0621-115821/proc.pdf chapter in Parallel Numerical
Algorithms, edited by D. Keyes, A. Semah, V. Venkatakrishnan, ICASE/LaRC Interdisciplinary Series in
Science and Engineering, Kluwer, pp. 167--202.
See Also
PCCreate(), PCSetType(), PCType (for list of available types), PC, PCSOR, MatOrderingType,
PCFactorSetZeroPivot(), PCFactorSetShiftSetType(), PCFactorSetAmount(),
PCFactorSetDropTolerance(),PCFactorSetFill(), PCFactorSetMatOrderingType(), PCFactorSetReuseOrdering(),
PCFactorSetLevels(), PCFactorSetUseInPlace(), PCFactorSetAllowDiagonalFill(), PCFactorSetPivotInBlocks()
Level:beginner
Location:src/ksp/pc/impls/factor/ilu/ilu.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages
Examples
src/ksp/pc/examples/tutorials/ex1.c.html
src/ksp/pc/examples/tutorials/ex3.c.html
src/ksp/ksp/examples/tutorials/ex7.c.html
src/ksp/ksp/examples/tutorials/ex8.c.html