Prob with shots-noise

[multiphaseCFD]

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Context:

Add shots-noise to prob() in the C++ layer.

Description of the Change:

prob(Observable<StateVectorT> &obs, size_t number_shots), prob(size_t number_shots) and prob(const std::vector<size_t> wires, size_t number_shots) were added for the probabilities of a full system and sub-system.

Benefits:

Possible Drawbacks:

Related GitHub Issues:

[maliasadi]

Thanks @multiphaseCFD! 💯 Looking forward to see this support in Catalyst :)

[AmintorDusko]

I have just a super small suggestion. Happy to approve!

[dime10]

Thanks @multiphaseCFD, looks great 💯 The only thing I'm wondering, shouldn't there be a function with an observable and shot argument?

[multiphaseCFD]

Thanks @multiphaseCFD, looks great 💯 The only thing I'm wondering, shouldn't there be a function with an observable and shot argument?

Thanks @dime10 ! probs(obs, num_shots) added.

[dime10]

Looks great 💯

The only thing that I find a bit confusing is the large amount of variations that exist for different measurement processes, and that don't always seem consistent or consistently available. For example, expval and var provide separate functions for:

• mp(obs)
• mp(obs, shots)

But probs combines them into one:

• mp(obs, shots=0)

And that's on top of other variations like probs()/probs(shots), and probs(wires)/probs(wires, shots), where they are separate as well 😅

But it's not a blocker :)

[multiphaseCFD]

Looks great 💯

The only thing that I find a bit confusing is the large amount of variations that exist for different measurement processes, and that don't always seem consistent or consistently available. For example, expval and var provide separate functions for:

• mp(obs)
• mp(obs, shots)

But probs combines them into one:

• mp(obs, shots=0)

And that's on top of other variations like probs()/probs(shots), and probs(wires)/probs(wires, shots), where they are separate as well 😅

But it's not a blocker :)

Thanks @dime10 ! The reason why mps except for probs accept (obs) and (obs, shots) is that I don't want to refactor our previous analytic implementations of other mps. 😅