✨ Environmental re-use for scalar product #79
Description
What's the problem this feature will solve?
If we want to measure multiple observables across the MPS, we do not currently utilize environments and perform each contraction from scratch.
Describe the solution you'd like
It would be nice if we check if we have multiple observables at multiple sites, then pre-compute the environments to speed this up. Something similar already exists in the TDVP code, so maybe that could be modfiied.