petsc-3.7.1 2016-05-15
Report Typos and Errors

PCMG

Use multigrid preconditioning. This preconditioner requires you provide additional information about the coarser grid matrices and restriction/interpolation operators.

Options Database Keys

-pc_mg_levels <nlevels> - number of levels including finest Many br
-pc_mg_cycle_type <v,w> - Many br
-pc_mg_smoothup <n> - number of smoothing steps after interpolation Many br
-pc_mg_smoothdown <n> - number of smoothing steps before applying restriction operator Many br
-pc_mg_type <additive,multiplicative,full,kaskade> - multiplicative is the default Many br
-pc_mg_log - log information about time spent on each level of the solver Many br
-pc_mg_galerkin - use Galerkin process to compute coarser operators, i.e. Acoarse = R A R' Many br
-pc_mg_multiplicative_cycles - number of cycles to use as the preconditioner (defaults to 1) Many br
-pc_mg_dump_matlab - dumps the matrices for each level and the restriction/interpolation matrices Many brto the Socket viewer for reading from MATLAB. Many br
-pc_mg_dump_binary - dumps the matrices for each level and the restriction/interpolation matrices Many brto the binary output file called binaryoutput Many br

Notes: By default this uses GMRES on the fine grid smoother so this should be used with KSPFGMRES or the smoother changed to not use GMRES Many br

When run with a single level the smoother options are used on that level NOT the coarse grid solver options Many br

Many br

See Also

PCCreate(), PCSetType(), PCType (for list of available types), PC, PCMGType, PCEXOTIC, PCGAMG, PCML, PCHYPRE
PCMGSetLevels(), PCMGGetLevels(), PCMGSetType(), PCMGSetCycleType(), PCMGSetNumberSmoothDown(), Many brPCMGSetNumberSmoothUp(), PCMGGetCoarseSolve(), PCMGSetResidual(), PCMGSetInterpolation(), Many brPCMGSetRestriction(), PCMGGetSmoother(), PCMGGetSmootherUp(), PCMGGetSmootherDown(), Many brPCMGSetCycleTypeOnLevel(), PCMGSetRhs(), PCMGSetX(), PCMGSetR() Many br

Level:intermediate
Location:
src/ksp/pc/impls/mg/mg.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/ksp/ksp/examples/tutorials/ex42.c.html
src/snes/examples/tutorials/ex12.c.html