Open Qottmann opened 1 month ago
Thanks @Qottmann! Just double checking, does #6075 aim to resolve this? It wasn't clear to me from the PR (as the description is blank)
Thanks @Qottmann! Just double checking, does https://github.com/PennyLaneAI/pennylane/pull/6075 aim to resolve this? It wasn't clear to me from the PR (as the description is blank)
Yes! Though it is currently not a full fix and we are still not sure how best to resolve it. Linear independence in a stable fashion is hard apparently 😢
@josh146 Sorry for the blank description, I thought this was going to be a very quick fix that is not even worth triaging. However, it turned out to be more complex after discussions on the PR.
We need to re-triage this issue, in my opinion, as it was found that neither @Qottmann nor I can guarantee to work on this soon.
Thanks! I guess one question; does the open PR improve the behaviour even if it doesn't resolve it fully?
Yep I think so, because a previously failing case is fixed by it (see test addition). However, as this is about numerical precision and the like, there might be a new edge case lingering somewhere that stops working due to the PR, I suppose :thinking: Although it would surprise me.
Got it, thanks @dwierichs!
Running into this problem a lot when using sums of paulis, wonder how we can make this more reliable and stable (ideally with no significant performance regression).
In instances where the code breaks, I often find myself with large sums of Paulis with large coefficients, which makes me wonder whether picking up this old suggestion by @vincentmr could help?
An example: