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# DMPlexIsSimplex
Is the first cell in this mesh a simplex?
## Synopsis
```
#include "petscdmplex.h"
PetscErrorCode DMPlexIsSimplex(DM dm, PetscBool *simplex)
```
## Input Parameter
- ***dm -*** The `DMPLEX` object
## Output Parameter
- ***simplex -*** Flag checking for a simplex
## Note
This just gives the first range of cells found. If the mesh has several cell types, it will only give the first.
If the mesh has no cells, this returns `PETSC_FALSE`.
## See Also
[](ch_unstructured), `DM`, `DMPLEX`, `DMPlexGetSimplexOrBoxCells()`, `DMPlexGetCellType()`, `DMPlexGetHeightStratum()`, `DMPolytopeTypeGetNumVertices()`
## Level
intermediate
## Location
src/dm/impls/plex/plex.c
## Examples
src/dm/field/tutorials/ex1.c
src/snes/tutorials/ex12.c
src/snes/tutorials/ex23.c
src/snes/tutorials/ex36.c
src/snes/tutorials/ex62.c
src/snes/tutorials/ex71.c
src/snes/tutorials/ex76.c
src/snes/tutorials/ex77.c
src/ts/tutorials/ex46.c
src/ts/tutorials/ex47.c
src/ts/tutorials/ex53.c
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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/dm/impls/plex/plex.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)