:orphan:
# PCShellSetApplyBA
Sets routine to use as preconditioner times operator. 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCShellSetApplyBA(PC pc, PetscErrorCode (*applyBA)(PC, PCSide, Vec, Vec, Vec))
```
Logically Collective


## Input Parameters

- ***pc -*** the preconditioner context
- ***applyBA -*** the application-provided BA routine



## Calling sequence of `applyBA`
```none
   PetscErrorCode applyBA(PC pc, Vec xin, Vec xout)
```


- ***pc -*** the preconditioner, get the application context with `PCShellGetContext()`
- ***xin -*** input vector
- ***xout -*** output vector





## See Also
 `PCSHELL`, `PCShellSetApplyRichardson()`, `PCShellSetSetUp()`, `PCShellSetApplyTranspose()`, `PCShellSetContext()`, `PCShellSetApply()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/shell/shellpc.c.html#PCShellSetApplyBA">src/ksp/pc/impls/shell/shellpc.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/shell/shellpc.c.html#PCShellSetApplyBA_Shell(PC pc, PetscErrorCode (*applyBA)">PCShellSetApplyBA_Shell(PC pc, PetscErrorCode (*applyBA) in src/ksp/pc/impls/shell/shellpc.c</A><BR>


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