Stephan Rave

We could have an `scalar_data` attribute which is either `None` or a structured array (or better dict of arrays?) with the same length as the array. The `scalar_data` is copied/deleted...

I don't know about this one. My impression is that some more discussion of the concrete semantics and the effort required to implement this would be helpful. We should also...

Regarding the bus factor: @ftalbrecht might be a possible second maintainer.

> Could this be an external script that gets a VTK file as input instead? Maybe this already exists too? If you are referring to the triangle case: The code...

To continue the discussion from #730, @pmli : I think I would like `map_dofs` as a name for the method. It should always return a new array. At least for...

@renefritze, what do you think? BTW, we will probably use sympy to define `Functions` for external discretizers, gut I guess the situation is somewhat different there.

> It should always return a new array. I think we should reconsider. Returning a new array means twice the memory usage, which may be too much. On the other...

> Yes, that is by design, and maybe the expectation for RB methods. @sdrave is more familiar with this. At pyMOR school we discussed that it might be helpful to...

Fixes #1717.

Hmm, are issues only linked when they are mentioned in the first comment?