/*@
KSPUnwindPreconditioner - Unwinds the preconditioning in the solution. That is,
takes solution to the preconditioned problem and gets the solution to the
original problem from it.
Collective on KSP
Input Parameters:
+ ksp - iterative context
. vsoln - solution vector
- vt1 - temporary work vector
Output Parameter:
. vsoln - contains solution on output
Notes:
If preconditioning either symmetrically or on the right, this routine solves
for the correction to the unpreconditioned problem. If preconditioning on
the left, nothing is done.
Level: advanced
.keywords: KSP, unwind, preconditioner
.seealso: KSPSetPCSide()
@*/
PetscErrorCode KSPUnwindPreconditioner(KSP ksp,Vec vsoln,Vec vt1)
{
PetscErrorCode ierr;
PetscFunctionBegin;
PetscValidHeaderSpecific(ksp,KSP_CLASSID,1);
PetscValidHeaderSpecific(vsoln,VEC_CLASSID,2);
if (!ksp->pc) {ierr = KSPGetPC(ksp,&ksp->pc);CHKERRQ(ierr);}
if (ksp->pc_side == PC_RIGHT) {
ierr = KSP_PCApply(ksp,vsoln,vt1);CHKERRQ(ierr);
ierr = PCDiagonalScaleRight(ksp->pc,vt1,vsoln);CHKERRQ(ierr);
} else if (ksp->pc_side == PC_SYMMETRIC) {
ierr = PCApplySymmetricRight(ksp->pc,vsoln,vt1);CHKERRQ(ierr);
ierr = VecCopy(vt1,vsoln);CHKERRQ(ierr);
} else {
ierr = PCDiagonalScaleRight(ksp->pc,vsoln,vsoln);CHKERRQ(ierr);
}
PetscFunctionReturn(0);
}
PETSC_EXTERN void PETSC_STDCALL pcdiagonalscaleright_(PC pc,Vec in,Vec out, int *__ierr ){
*__ierr = PCDiagonalScaleRight(
(PC)PetscToPointer((pc) ),
(Vec)PetscToPointer((in) ),
(Vec)PetscToPointer((out) ));
}
