# VecTaggerComputeIS
Use a VecTagger context to tag a set of indices based on a vector's values 
## Synopsis
```
#include "petscvec.h" 
PetscErrorCode VecTaggerComputeIS(VecTagger tagger, Vec vec, IS *is, PetscBool *listed)
```
Collective on VecTagger


## Input Parameters

- ***tagger -*** the VecTagger context
- ***vec -*** the vec to tag



## Output Parameters

- ***IS -*** a list of the indices tagged by the tagger, i.e., if the number of local indices will be n / bs, where n is VecGetLocalSize() and bs is VecTaggerGetBlockSize().
- ***listed -*** routine was able to compute the IS, pass in NULL if not needed





## See Also
 `VecTaggerComputeBoxes()`, `VecTagger`, `VecTaggerCreate()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/utils/tagger/interface/tagger.c.html#VecTaggerComputeIS">src/vec/vec/utils/tagger/interface/tagger.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/utils/tagger/tutorials/ex1.c.html">src/vec/vec/utils/tagger/tutorials/ex1.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex11.c.html">src/ts/tutorials/ex11.c.html</A><BR>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/utils/tagger/impls/and.c.html#VecTaggerComputeIS_And">VecTaggerComputeIS_And in src/vec/vec/utils/tagger/impls/and.c</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/utils/tagger/impls/or.c.html#VecTaggerComputeIS_Or">VecTaggerComputeIS_Or in src/vec/vec/utils/tagger/impls/or.c</A><BR>


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


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