# Re: [deal.II] Interpolating values of the neighbor cells in DG

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Jiaqi,```
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```Yes, I want to extend the solution from the neighboring cells to the current
cell. I know different cells have different polynomial descriptions,
but in order to apply the limiters, information from the neighbor cells is
required. Is it possible to extend the solutions from neighbors through
interpolation? I am not sure how to do that in deal.II.
```
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This is one of those operations that are easy to write down in formulas and difficult to implement.
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```
Are you using arbitrary meshes, or rectangular ones? I ask because what you really want to do is evaluate the solution on one cell at points *outside this cell*. That's possible, but you will need to know the reference coordinates of a point on a neighboring cell in the coordinate system of the current cell. This is simple if you are on a rectangular mesh, but not so simple in the general case.
```
Best
W.

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Wolfgang Bangerth          email:                 bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

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