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# DMLABELEPHEMERAL
"ephemeral" - This type of `DMLabel` is used to label ephemeral meshes. Ephemeral meshes are never concretely instantiated, but rather the answers to queries are created on the fly from a base mesh and a `DMPlexTransform` object.
For example, we could integrate over a refined mesh without ever storing the entire thing, just producing each cell closure one at a time. The label consists
of a base label and the same transform. Stratum are produced on demand, so that the time is in $O(max(M, N))$ where $M$ is the size of the original stratum,
and $N$ is the size of the output stratum. Queries take the same time, since we cannot sort the output.




## See Also
 `DMLabel`, `DM`, `DMLabelType`, `DMLabelCreate()`, `DMLabelSetType()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/label/impls/ephemeral/dmlabeleph.c.html#DMLABELEPHEMERAL">src/dm/label/impls/ephemeral/dmlabeleph.c</A>


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


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