# 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



## Note
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.




## See Also
 [](chapter_ksp), `KSP`, `KSPSetPCSide()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/interface/itres.c.html#KSPUnwindPreconditioner">src/ksp/ksp/interface/itres.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/ksp/interface/itres.c)


[Index of all KSP routines](index.md)  
[Table of Contents for all manual pages](/docs/manualpages/index.md)  
[Index of all manual pages](/docs/manualpages/singleindex.md)  
