petsc-3.10.5 2019-03-28
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# 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.

### Synopsis

    #include "petscksp.h"
    PetscErrorCode  KSPUnwindPreconditioner(KSP ksp,Vec vsoln,Vec vt1)

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.

### Keywords

KSP, unwind, preconditioner

### See Also

KSPSetPCSide()

### Level

advanced

### Location

src/ksp/ksp/interface/itres.c
Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages