:orphan:
# ISLocalToGlobalMappingCreateSF
Creates a mapping between a local (0 to n) ordering and a global parallel ordering. 
## Synopsis
```
#include "petscis.h"  
PetscErrorCode ISLocalToGlobalMappingCreateSF(PetscSF sf, PetscInt start, ISLocalToGlobalMapping *mapping)
```
Collective


## Input Parameters

- ***sf -*** star forest mapping contiguous local indices to (rank, offset)
- ***start -*** first global index on this process, or `PETSC_DECIDE` to compute contiguous global numbering automatically



## Output Parameter

- ***mapping -*** new mapping data structure





## Note
If any processor calls this with `start` = `PETSC_DECIDE` then all processors must, otherwise the program will hang.


## See Also
 [](sec_scatter), `PetscSF`, `ISLocalToGlobalMappingDestroy()`, `ISLocalToGlobalMappingCreate()`, `ISLocalToGlobalMappingCreateIS()`, `ISLocalToGlobalMappingSetFromOptions()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/is/utils/isltog.c.html#ISLocalToGlobalMappingCreateSF">src/vec/is/utils/isltog.c</A>


---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/vec/is/utils/isltog.c)


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