# PCGalerkinSetInterpolation
Sets the interpolation operator for the `PCGALERKIN` preconditioner 
## Synopsis
```
#include "petscksp.h" 
PetscErrorCode PCGalerkinSetInterpolation(PC pc, Mat P)
```
Logically Collective on pc


## Input Parameters

- ***pc -*** the preconditioner context
- ***R -*** the interpolation operator



## Note
Either this or `PCGalerkinSetRestriction()` or both must be called




## See Also
 `PCCreate()`, `PCSetType()`, `PCType`, `PCGALERKIN`,
`PCGalerkinSetRestriction()`, `PCGalerkinGetKSP()`

## Level
Intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/galerkin/galerkin.c.html#PCGalerkinSetInterpolation">src/ksp/pc/impls/galerkin/galerkin.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/galerkin/galerkin.c.html#PCGalerkinSetInterpolation_Galerkin">PCGalerkinSetInterpolation_Galerkin in src/ksp/pc/impls/galerkin/galerkin.c</A><BR>


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


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