:orphan:
# DMCreateInterpolationScale
Forms L = 1/(R*1) where 1 is the vector of all ones, and R is the transpose of the interpolation between the `DM`. xcoarse = diag(L)*R*xfine preserves scale and is thus suitable for state (versus residual) restriction. In other words xcoarse is the coarse representation of xfine. 
## Synopsis
```
#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMCreateInterpolationScale(DM dac, DM daf, Mat mat, Vec *scale)
```

## Input Parameters

- ***dac -*** `DM` that defines a coarse mesh
- ***daf -*** `DM` that defines a fine mesh
- ***mat -*** the restriction (or interpolation operator) from fine to coarse



## Output Parameter

- ***scale -*** the scaled vector





## Developer Note
If the fine-scale `DMDA` has the -dm_bind_below option set to true, then `DMCreateInterpolationScale()` calls `MatSetBindingPropagates()`
on the restriction/interpolation operator to set the bindingpropagates flag to true.


## See Also
 [](ch_dmbase), `DM`, `MatRestrict()`, `MatInterpolate()`, `DMCreateInterpolation()`, DMCreateRestriction()`, `DMCreateGlobalVector()`

## Level
advanced

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


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