# PCGAMGASMSetUseAggs
Have the `PCGAMG` smoother on each level use the aggregates defined by the coarsening process as the subdomains for the additive Schwarz preconditioner used as the smoother 
## Synopsis
```
#include "petscpc.h" 
#include "petscksp.h" 
PetscErrorCode PCGAMGASMSetUseAggs(PC pc, PetscBool flg)
```
Collective on pc


## Input Parameters

- ***pc -*** the preconditioner context
- ***flg -*** `PETSC_TRUE` to use aggregates, `PETSC_FALSE` to not



## Options Database Key

- ***-pc_gamg_asm_use_agg <true,false> -*** use aggregates to define the additive Schwarz subdomains





## See Also
 `PCGAMG`, `PCASM`, `PCSetType`

## Level
intermediate

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

## Implementations

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


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


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