# DMPlexIsInterpolatedCollective
Find out to what extent the DMPlex is topologically interpolated (in collective manner). 
## Synopsis
```
#include "petscdmplex.h"   
PetscErrorCode DMPlexIsInterpolatedCollective(DM dm, DMPlexInterpolatedFlag *interpolated)
```
Collective


## Input Parameter

- ***dm      -*** The DM object



## Output Parameter

- ***interpolated -*** Flag whether the DM is interpolated





## Notes
Unlike DMPlexIsInterpolated(), this is collective so the results are guaranteed to be the same on all ranks.

This function will return DMPLEX_INTERPOLATED_MIXED if the results of DMPlexIsInterpolated() are different on different ranks.


## Developer Notes
Initially, plex->interpolatedCollective = DMPLEX_INTERPOLATED_INVALID.

If plex->interpolatedCollective == DMPLEX_INTERPOLATED_INVALID, this function calls DMPlexIsInterpolated() which sets plex->interpolated.
MPI_Allreduce() is then called and collectively consistent flag plex->interpolatedCollective is set and returned;
if plex->interpolated varies on different ranks, plex->interpolatedCollective = DMPLEX_INTERPOLATED_MIXED,
otherwise sets plex->interpolatedCollective = plex->interpolated.

If plex->interpolatedCollective != DMPLEX_INTERPOLATED_INVALID, this function just returns plex->interpolatedCollective.


## See Also
 `DMPlexInterpolate()`, `DMPlexIsInterpolated()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/plex/plexinterpolate.c.html#DMPlexIsInterpolatedCollective">src/dm/impls/plex/plexinterpolate.c</A>


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


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