petscmaster 20201202
PCDeflationSetSpace
Set the deflation space matrix (or its (Hermitian) transpose).
Synopsis
#include "petscksp.h"
PetscErrorCode PCDeflationSetSpace(PC pc,Mat W,PetscBool transpose)
Logically Collective
Input Parameters
 pc   the preconditioner context

 W   deflation matrix

 transpose   indicates that W is an explicit transpose of the deflation matrix

Notes
Setting W as a multipliplicative MATCOMPOSITE enables use of the multilevel
deflation. If W = W0*W1*W2*...*Wn, W0 is taken as the first deflation space and
the coarse problem (W0'*A*W0)^{1} is again preconditioned by deflation with
W1 as the deflation matrix. This repeats until the maximum level set by
PCDeflationSetLevels() is reached or there are no more matrices available.
If there are matrices left after reaching the maximum level,
they are merged into a deflation matrix ...*W{n1}*Wn.
See Also
PCDeflationSetLevels(), PCDEFLATION
Level
intermediate
Location
src/ksp/pc/impls/deflation/deflation.c
Implementations
PCDeflationSetSpace_Deflation in src/ksp/pc/impls/deflation/deflation.c
Index of all PC routines
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Index of all manual pages