# PCHYPRESetDiscreteCurl
Set discrete curl matrx for `PCHYPRE` type of ads 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCHYPRESetDiscreteCurl(PC pc, Mat C)
```
Collective


## Input Parameters

- ***pc -*** the preconditioning context
- ***C -*** the discrete curl





## Notes
C should have as many rows as the number of faces and as many columns as the number of edges in the mesh

Each row of G has as many nonzeros as the number of edges of a face, with column indexes being the global indexes of the corresponding edge: matrix entries are +1 and -1 depending on edge orientation with respect to the face orientation


## Developer Note
This automatically converts the matrix to `MATHYPRE` if it is not already of that type

If this is only for  `PCHYPRE` type of ads it should be called `PCHYPREADSSetDiscreteCurl()`


## See Also
 `PCHYPRE`, `PCHYPRESetDiscreteGradient()`

## Level
intermediate

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

## Implementations

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


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


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