petsc-3.13.6 2020-09-29
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PCLU

Uses a direct solver, based on LU factorization, as a preconditioner

Options Database Keys

-pc_factor_reuse_ordering - Activate PCFactorSetReuseOrdering()
-pc_factor_mat_solver_type - Actives PCFactorSetMatSolverType() to choose the direct solver, like superlu
-pc_factor_reuse_fill - Activates PCFactorSetReuseFill()
-pc_factor_fill <fill> - Sets fill amount
-pc_factor_in_place - Activates in-place factorization
-pc_factor_mat_ordering_type <nd,rcm,...> - Sets ordering routine
-pc_factor_pivot_in_blocks <true,false> - allow pivoting within the small blocks during factorization (may increase stability of factorization.
-pc_factor_shift_type <shifttype> - Sets shift type or PETSC_DECIDE for the default; use '-help' for a list of available types
-pc_factor_shift_amount <shiftamount> - Sets shift amount or PETSC_DECIDE for the default
-pc_factor_nonzeros_along_diagonal - permutes the rows and columns to try to put nonzero value along the diagonal.

Notes

Not all options work for all matrix formats Run with -help to see additional options for particular matrix formats or factorization algorithms

Notes

Usually this will compute an "exact" solution in one iteration and does not need a Krylov method (i.e. you can use -ksp_type preonly, or KSPSetType(ksp,KSPPREONLY) for the Krylov method

See Also

PCCreate(), PCSetType(), PCType (for list of available types), PC,
PCILU, PCCHOLESKY, PCICC, PCFactorSetReuseOrdering(), PCFactorSetReuseFill(), PCFactorGetMatrix(), PCFactorSetFill(), PCFactorSetUseInPlace(), PCFactorSetMatOrderingType(), PCFactorSetColumnPivot(), PCFactorSetPivotingInBlocks(),PCFactorSetShiftType(),PCFactorSetShiftAmount() PCFactorReorderForNonzeroDiagonal()

Level

beginner

Location

src/ksp/pc/impls/factor/lu/lu.c

Examples

src/ksp/ksp/tutorials/ex13.c.html
src/ksp/ksp/tutorials/ex52.c.html
src/ksp/ksp/tutorials/ex53.c.html
src/ksp/ksp/tutorials/ex68.c.html
src/ksp/ksp/tutorials/ex69.c.html
src/ksp/ksp/tutorials/ex13f90.F90.html
src/ksp/ksp/tutorials/ex52f.F90.html
src/ksp/ksp/tutorials/ex61f.F90.html
src/tao/constrained/tutorials/maros.c.html
src/tao/constrained/tutorials/toy.c.html
src/tao/constrained/tutorials/ex1.c.html

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