PCCHOLESKY#
Uses a direct solver, based on Cholesky 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
- Sets the explected fill amount-pc_factor_in_place - Activates in-place factorization
-pc_factor_mat_ordering_type <nd,rcm,…> - Sets ordering routine used to determine the order the rows are used in the factorization to reduce fill and thus be more effective
Notes#
The Cholesky factorization direct solver, PCCHOLESKY is only for symmetric positive-definite (SPD) matrices. For such
SPD matrices it is more efficient than using the LU factorization direct solver, PCLU.
Not all options work for all matrix formats
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#
KSP: Linear System Solvers, PCCreate(), PCSetType(), PCType, PC,
PCILU, PCLU, PCICC, PCFactorSetReuseOrdering(), PCFactorSetReuseFill(), PCFactorGetMatrix(),
PCFactorSetFill(), PCFactorSetShiftType(), PCFactorSetShiftAmount()
PCFactorSetUseInPlace(), PCFactorGetUseInPlace(), PCFactorSetMatOrderingType(), PCFactorSetReuseOrdering()
Level#
beginner
Location#
Examples#
src/ksp/ksp/tutorials/ex52.c
src/tao/constrained/tutorials/ex1.c
src/ksp/pc/tutorials/ex4.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages