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# DMPlexGetFaceFields
Retrieve the field values values for a chunk of faces 
## Synopsis
```
#include "petscdmplex.h"   
PetscErrorCode DMPlexGetFaceFields(DM dm, PetscInt fStart, PetscInt fEnd, Vec locX, Vec locX_t, Vec faceGeometry, Vec cellGeometry, Vec locGrad, PetscInt *Nface, PetscScalar **uL, PetscScalar **uR)
```

## Input Parameters

- ***dm     -*** The `DM`
- ***fStart -*** The first face to include
- ***fEnd   -*** The first face to exclude
- ***locX   -*** A local vector with the solution fields
- ***locX_t -*** A local vector with solution field time derivatives, or NULL
- ***faceGeometry -*** A local vector with face geometry
- ***cellGeometry -*** A local vector with cell geometry
- ***locaGrad -*** A local vector with field gradients, or NULL



## Output Parameters

- ***Nface -*** The number of faces with field values
- ***uL -*** The field values at the left side of the face
- ***uR -*** The field values at the right side of the face





## See Also
 [](ch_unstructured), `DM`, `DMPLEX`, `DMPlexGetCellFields()`

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/plex/plexfem.c.html#DMPlexGetFaceFields">src/dm/impls/plex/plexfem.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/dm/impls/plex/plexfem.c)


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