:orphan:
# PCGASMSetUseDMSubdomains
Indicates whether to use `DMCreateDomainDecomposition()` to define the subdomains, whenever possible for `PCGASM` 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCGASMSetUseDMSubdomains(PC pc, PetscBool flg)
```
Logically Collective


## Input Parameters

- ***pc  -*** the preconditioner
- ***flg -*** boolean indicating whether to use subdomains defined by the `DM`



## Options Database Key

- ***-pc_gasm_dm_subdomains -*** pc_gasm_overlap -pc_gasm_total_subdomains





## Note
`PCGASMSetSubdomains()`, `PCGASMSetTotalSubdomains()` or `PCGASMSetOverlap()` take precedence over `PCGASMSetUseDMSubdomains()`,
so setting `PCGASMSetSubdomains()` with nontrivial subdomain ISs or any of `PCGASMSetTotalSubdomains()` and `PCGASMSetOverlap()`
automatically turns the latter off.


## See Also
 `PCGASM`, `PCGASMGetUseDMSubdomains()`, `PCGASMSetSubdomains()`, `PCGASMSetOverlap()`
`PCGASMCreateSubdomains2D()`

## Level
intermediate

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


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


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