:orphan:
# DMLocatePoints
Locate the points in v in the mesh and return a `PetscSF` of the containing cells 
## Synopsis
```
#include "petscdm.h"          
PetscErrorCode DMLocatePoints(DM dm, Vec v, DMPointLocationType ltype, PetscSF *cellSF)
```
Collective


## Input Parameters

- ***dm -*** The `DM`
- ***ltype -*** The type of point location, e.g. `DM_POINTLOCATION_NONE` or `DM_POINTLOCATION_NEAREST`



## Input/Output Parameters

- ***v -*** The `Vec` of points, on output contains the nearest mesh points to the given points if `DM_POINTLOCATION_NEAREST` is used
- ***cellSF -*** Points to either `NULL`, or a `PetscSF` with guesses for which cells contain each point;
on output, the `PetscSF` containing the ranks and local indices of the containing points





## Notes
To do a search of the local cells of the mesh, v should have `PETSC_COMM_SELF` as its communicator.
To do a search of all the cells in the distributed mesh, `v` should have the same communicator as `dm`.

Points will only be located in owned cells, not overlap cells arising from `DMPlexDistribute()` or other overlapping distributions.

If *cellSF is `NULL` on input, a `PetscSF` will be created.
If *cellSF is not `NULL` on input, it should point to an existing `PetscSF`, whose graph will be used as initial guesses.

An array that maps each point to its containing cell can be obtained with
```none
    const PetscSFNode *cells;
    PetscInt           nFound;
    const PetscInt    *found;

    PetscSFGetGraph(cellSF,NULL,&nFound,&found,&cells);
```


Where cells[i].rank is the rank of the process owning the cell containing point found[i] (or i if found == NULL), and cells[i].index is
the index of the cell in its rank's local numbering. This rank is in the communicator for `v`, so if `v` is on `PETSC_COMM_SELF` then the rank will always be 0.


## See Also
 `DM`, `DMSetCoordinates()`, `DMSetCoordinatesLocal()`, `DMGetCoordinates()`, `DMGetCoordinatesLocal()`, `DMPointLocationType`

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/interface/dmcoordinates.c.html#DMLocatePoints">src/dm/interface/dmcoordinates.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/impls/plex/plexgeometry.c.html#DMLocatePoints_Plex">DMLocatePoints_Plex in src/dm/impls/plex/plexgeometry.c</A><BR>


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


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