petsc-3.14.6 2021-03-30
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PCCOMPOSITE

 Build a preconditioner by composing together several preconditioners

Options Database Keys

-pc_composite_type <type: one of multiplicative, additive, symmetric_multiplicative, special> - Sets composite preconditioner type
-pc_use_amat - activates PCSetUseAmat()
-pc_composite_pcs - <pc0,pc1,...> list of PCs to compose

Notes

To use a Krylov method inside the composite preconditioner, set the PCType of one or more inner PCs to be PCKSP. Using a Krylov method inside another Krylov method can be dangerous (you get divergence or the incorrect answer) unless you use KSPFGMRES as the outer Krylov method To use a different operator to construct one of the inner preconditioners first call PCCompositeGetPC(), then call PCSetOperators() on that PC.

See Also

PCCreate(), PCSetType(), PCType (for list of available types), PC,
PCSHELL, PCKSP, PCCompositeSetType(), PCCompositeSpecialSetAlpha(), PCCompositeAddPC(), PCCompositeGetPC(), PCSetUseAmat()

Level

intermediate

Location

src/ksp/pc/impls/composite/composite.c

Examples

src/ksp/ksp/tutorials/ex71.c.html

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