[dune-fem] Interpolation of discrete function over a different grid

[Agnese, Marco]

Hi!

I have a discrete function df1 defined over grid1 and a discrete function df2 over grid2. The domain is the same but grid1 != grid2.
I want to interpolate df1 onto grid2 and store the value into df2. Which is the correct way to do it?

Right now I am looping trough the entities of grid2, evaluating df1 in its Lagrange points and storing the result in the correct place of df2. 
But this approach is not very general. Moreover, since the access to Lagrange points is going to be removed, it won't be possible to do this in the future so I am looking to a better solution. Any suggestions?

Thank you very much,
cheers,
Marco.