:orphan:
# PCFieldSplitGetISByIndex
Retrieves the elements for a given split as an `IS` 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCFieldSplitGetISByIndex(PC pc, PetscInt index, IS *is)
```
Logically Collective


## Input Parameters

- ***pc  -*** the preconditioner context
- ***index -*** index of this split



## Output Parameter

- ***is -*** the index set that defines the elements in this split





## See Also
  [](sec_block_matrices), `PC`, `PCFieldSplitGetSubKSP()`, `PCFIELDSPLIT`, `PCFieldSplitGetIS()`, `PCFieldSplitSetIS()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/fieldsplit/fieldsplit.c.html#PCFieldSplitGetISByIndex">src/ksp/pc/impls/fieldsplit/fieldsplit.c</A>


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


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