Improve eigenstates

[johannes-moegerle]

No description provided.

[frederic-atom]

I like what you did here, in principle. It ensures the desired behavior for database generation.
I have a minor concern: The _mroots function naming suggest that a user won't access this function, but it's crucial for mroots. Should we find better names for at least on of the two functions?
And I have a major concern: What if, let's say for research purposes, I want to output eigenstates for a model outside the intended bounds? I think this is a very important feature, but with this MR we would lose that, right?

[johannes-moegerle]

I have a minor concern: The _mroots function naming suggest that a user won't access this function, but it's crucial for mroots. Should we find better names for at least on of the two functions?

actually we dont need the _mroots function at all, we can put everything in the mroots with N1-N2 and for mroots(N) just call mroots(N-05, N+0.5)

And I have a major concern: What if, let's say for research purposes, I want to output eigenstates for a model outside the intended bounds? I think this is a very important feature, but with this MR we would lose that, right?

I agree that this might be useful, so I added a keyword argument overwrite_model_limits to the eigenstates function