PCFieldSplitSchurPrecondition

Indicates if the Schur complement is preconditioned by a preconditioner constructed by the D matrix. Otherwise no preconditioner is used.

Synopsis

#include "petscpc.h" 
PetscErrorCode PETSCKSP_DLLEXPORT PCFieldSplitSchurPrecondition(PC pc,PCFieldSplitSchurPreType ptype,Mat pre)
Collective on PC

Input Parameters

pc - the preconditioner context
ptype - which matrix to use for preconditioning the Schur complement
userpre - matrix to use for preconditioning, or PETSC_NULL

Notes

The default is to use the block on the diagonal of the preconditioning matrix. This is D, in the (1,1) position. There are currently no preconditioners that work directly with the Schur complement so setting PC_FIELDSPLIT_SCHUR_PRE_SELF is observationally equivalent to -fieldsplit_1_pc_type none.

Options Database

-pc_fieldsplit_schur_precondition <self,user,diag> default is diag -

See Also

PCFieldSplitGetSubKSP(), PCFIELDSPLIT, PCFieldSplitSetFields(), PCFieldSplitSchurPreType

Level:intermediate
Location:
src/ksp/pc/impls/fieldsplit/fieldsplit.c
Index of all PC routines
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Index of all manual pages