PCCHOLESKY#
Uses a direct solver, based on Cholesky factorization, as a preconditioner
Options Database Keys#
-pc_factor_reuse_ordering (true|false) - Activate
PCFactorSetReuseOrdering()-pc_factor_mat_solver_type type - Actives
PCFactorSetMatSolverType()to choose the direct solver, likesuperlu-pc_factor_reuse_fill (true|false) - Activates
PCFactorSetReuseFill()-pc_factor_fill fill - Sets the explected fill amount
-pc_factor_in_place (true|false) - Activates in-place factorization
-pc_factor_mat_ordering_type type - Sets ordering routine used to determine the order the rows are used in the factorization to reduce fill, see
MatOrderingType-mat_solvertype_optionname - options for a specific solver package, for example
-mat_mumps_cntl_1
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
The options prefix of the factored matrix is set to be the same as the PC options prefix.
See Also#
KSP: Linear System Solvers, PCCreate(), PCSetType(), PCType, PC,
PCILU, PCLU, PCICC, PCFactorSetReuseOrdering(), PCFactorSetReuseFill(), PCFactorGetMatrix(),
PCFactorSetFill(), PCFactorSetShiftType(), PCFactorSetShiftAmount(),
PCFactorSetUseInPlace(), PCFactorGetUseInPlace(), PCFactorSetMatOrderingType()
Level#
beginner
Location#
Examples#
src/ksp/pc/tutorials/ex4.c
src/ksp/ksp/tutorials/ex57f.F90
src/ksp/ksp/tutorials/ex52.c
src/tao/constrained/tutorials/ex1.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages