-pc_icc_levels <k> | - number of levels of fill for ICC(k) | |
-pc_icc_in_place | - only for ICC(0) with natural ordering, reuses the space of the matrix for its factorization (overwrites original matrix) | |
-pc_icc_damping | - add damping to diagonal to prevent zero (or very small) pivots | |
-pc_icc_shift | - apply Manteuffel shift to diagonal to force positive definite preconditioner | |
-pc_icc_zeropivot <tol> | - set tolerance for what is considered a zero pivot | |
-pc_icc_fill <nfill> | - expected amount of fill in factored matrix compared to original matrix, nfill > 1 | |
-pc_icc_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 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 PCICCSetShift(pc,PETSC_FALSE); to turn off the shift.
Level:beginner
Location:src/ksp/pc/impls/icc/icc.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages