# PCHMGSetCoarseningComponent
Set which component of the PDE is used for the subspace-based coarsening algorithm 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCHMGSetCoarseningComponent(PC pc, PetscInt component)
```
Logically Collective


## Input Parameters

- ***pc -*** the `PCHMG` context
- ***component -*** which component `PC` will coarsen



## Options Database Key

- ***-pc_hmg_coarsening_component <i> -*** Which component is chosen for the subspace-based coarsening algorithm





## See Also
 `PCHMG`, `PCType`, `PCGAMG`, `PCHMGSetReuseInterpolation()`, `PCHMGSetUseSubspaceCoarsening()`, `PCHMGSetInnerPCType()`

## Level
beginner

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

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/tutorials/ex4.c.html">src/ksp/ksp/tutorials/ex4.c.html</A><BR>

## Implementations

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


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


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