:orphan:
# PCDeflationSetProjectionNullSpaceMat
Set the projection null space matrix (W'*A).
## Synopsis
```
#include "petscksp.h"
PetscErrorCode PCDeflationSetProjectionNullSpaceMat(PC pc, Mat mat)
```
Collective
## Input Parameters
- ***pc -*** preconditioner context
- ***mat -*** projection null space matrix
## See Also
`PCDEFLATION`, `PCDeflationSetSpace()`
## Level
developer
## Location
src/ksp/pc/impls/deflation/deflation.c
## Implementations
PCDeflationSetProjectionNullSpaceMat_Deflation in src/ksp/pc/impls/deflation/deflation.c
---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/pc/impls/deflation/deflation.c)
[Index of all PC routines](index.md)
[Table of Contents for all manual pages](/manualpages/index.md)
[Index of all manual pages](/manualpages/singleindex.md)