# PetscSFGetSubSF
Returns an SF for a specific subset of points. Leaves are re-numbered to reflect the new ordering 
## Synopsis
```
#include "petscdmnetwork.h"  
PetscErrorCode PetscSFGetSubSF(PetscSF mainsf, ISLocalToGlobalMapping map, PetscSF *subSF)
```
Collective


## Input Parameters

- ***mainSF -*** the original SF structure
- ***map -*** a ISLocalToGlobal mapping that contains the subset of points



## Output Parameter

- ***subSF -*** a subset of the mainSF for the desired subset.




## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/network/network.c.html#PetscSFGetSubSF">src/dm/impls/network/network.c</A>


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


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