Check qubit release/measurement status on release #796
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| } | ||
| return reinterpret_cast<Result>( | ||
| m(this->simulatorId, (unsigned)numBases, reinterpret_cast<unsigned*>(bases), ids.data())); | ||
| } |
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I have an impression that only one qubit is marked as measured regardless of the number of qubits being measured.
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One classical bit is returned, but that could come from a joint measurement on an arbitrary number of qubits. E.g.: Measure([PauliZ, PauliZ], [q0, q1]) collapses the state of [q0, q1] onto either the +1 or −1 eigenspace of 𝑍 ⊗ 𝑍, spanned by {|00⟩, |11⟩} and {|01⟩, |10⟩}, respectively.
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If multiple qubits are measured it doesn't guarantee that the individual qubit state is known. Only when the length of ids is 1 (ie: when only a single qubit is being measured and not a joint measurement) do we want to mark that qubit as measured and safe to release.
cgranade
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Some of these comments seemed to get stuck in a pending review, sorry. Probably out of date now...
This mimicks the same behavior in the QIR Runtime wrapper for the fullstate simulator as what we have for C#, namely that a qubit is falid for release if and only if it is either in the ground state or the last operation on that qubit was measure.
This fixes #552, and supercedes #710.