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# SNESSetNPCSide
Sets the preconditioning side. 
## Synopsis
```
#include "petscsnes.h"  
PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
```
Logically Collective


## Input Parameter

- ***snes -*** iterative context obtained from `SNESCreate()`



## Output Parameter

- ***side -*** the preconditioning side, where side is one of


```none
      PC_LEFT - left preconditioning
      PC_RIGHT - right preconditioning (default for most nonlinear solvers)
```



## Options Database Key

- ***-snes_npc_side <right,left> -*** nonlinear preconditioner side





## Note
`SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.


## See Also
 [](ch_snes), `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/interface/snes.c.html#SNESSetNPCSide">src/snes/interface/snes.c</A>


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


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