Support new-style Bit in Pauli convertor from QuantumCircuit #10757
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This is also more correct, so that's good too. I strongly suspect that this PR also fixes this code block:
from qiskit.quantum_info import Pauli
from qiskit.circuit import Qubit, QuantumCircuit
qc = QuantumCircuit([Qubit()])
qc.x(0)
Pauli(qc)Would you like to add a test and a bugfix release note about that?
I was unaware of the issue. Redoing this PR as a bugfix in 0347975 . thanks! |
1ucian0
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Bit.index in quantum_info/operators/symplectic/pauli.py
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Changelog: Bugfix
| @@ -157,7 +157,12 @@ class initialization (``Pauli('-iXYZ')``). A ``Pauli`` object can be | |||
| _CANONICAL_PHASE_LABEL = {"": 0, "-i": 1, "-": 2, "i": 3} | |||
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| def __init__( | |||
| self, data: str | tuple | Pauli | ScalarOp | None = None, x=None, *, z=None, label=None | |||
| self, | |||
| data: str | tuple | Pauli | ScalarOp | QuantumCircuit | None = None, | |||
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Unrelated. I just noticed that the type hint for calling _from_circuit was missing.
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stable backport potential
releasenotes/notes/fix_pauli_new_style_bit-0704933127b4debe.yaml
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Yeah, I wasn't aware of it as a bug before this PR either - I had a quick look through our issues but didn't see anything - it was just clear from the code change that it couldn't have handled loose qubits, so I made a quick failure-path demo. Thanks for fixing it!
jakelishman
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mod: quantum info
* Do not use Bit.index in quantum_info/operators/symplectic/pauli.py * bugfix * Fix cross-reference --------- Co-authored-by: Jake Lishman <jake@binhbar.com> (cherry picked from commit 89ea58b)
Internal dunder code in quantum_info/operators/symplectic/pauli.py was still using Bit.index access, which is deprecated since 0.17 (see #10744).
Because
tupis coming from a QuantumCircuit in scope (instr), it is easy to fix withfind_bit.