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# PetscSectionSetClosureIndex
Create an internal data structure to speed up closure queries. 
## Synopsis
```
#include "petscsection.h"   
PetscErrorCode PetscSectionSetClosureIndex(PetscSection section, PetscObject obj, PetscSection clSection, IS clPoints)
```
Collective


## Input Parameters

- ***section   -*** The `PetscSection`
- ***obj       -*** A `PetscObject` which serves as the key for this index
- ***clSection -*** `PetscSection` giving the size of the closure of each point
- ***clPoints  -*** `IS` giving the points in each closure





## Note
This function creates an internal map from each point to its closure. We compress out closure points with no dofs in this section.


## Developer Note
The information provided here is completely opaque


## See Also
 [PetscSection](sec_petscsection), `PetscSection`, `PetscSectionGetClosureIndex()`, `DMPlexCreateClosureIndex()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/section/interface/section.c.html#PetscSectionSetClosureIndex">src/vec/is/section/interface/section.c</A>


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