Pol Febrer Calabozo

Does `np.trace` already work? I don't know if it's a good idea to introduce the matrix multiplication on a simple `trace` method, because it feels like an arbitrary choice (you...

But it is also true that you can acheive that simply with `np.sum(H * dm)` :thinking: I wonder if having the explicit method helps, because I had not thinked that...

> Hmm, I think we shouldn't do complicated functions that are allready standardized, e.g. matmul and trace. Yes, but the point is that `trace(matmul(X))` doesn't actually require `matmul(X)` > Well,...

I think it is simpler to make something like `np.sum(H * H.S)` work. That doesn't necessarily involve separating the overlap in storage as I understand you propose in #770.