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# PCShellSetSetUp
Sets routine to use to "setup" the preconditioner whenever the matrix operator is changed.
## Synopsis
```
#include "petscpc.h"
PetscErrorCode PCShellSetSetUp(PC pc, PetscErrorCode (*setup)(PC))
```
Logically Collective
## Input Parameters
- ***pc -*** the preconditioner context
- ***setup -*** the application-provided setup routine
## Calling sequence of `setup`
```none
PetscErrorCode setup(PC pc)
```
- ***pc -*** the preconditioner, get the application context with `PCShellGetContext()`
## Note
the function MUST return an error code of 0 on success and nonzero on failure.
## See Also
`PCSHELL`, `PCShellSetApplyRichardson()`, `PCShellSetApply()`, `PCShellSetContext()`
## Level
intermediate
## Location
src/ksp/pc/impls/shell/shellpc.c
## Examples
src/ksp/ksp/tutorials/ex15f.F90
src/ksp/ksp/tutorials/ex60.c
## Implementations
PCShellSetSetUp_Shell(PC pc, PetscErrorCode (*setup) in src/ksp/pc/impls/shell/shellpc.c
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[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)