qubits are never freed in many cirq-style decompositions of arithmetic gates

quantumlib / Qualtran

Qᴜᴀʟᴛʀᴀɴ is a Python library for expressing and analyzing Fault Tolerant Quantum algorithms.

https://qualtran.readthedocs.io/en/latest/

Apache License 2.0

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qubits are never freed in many cirq-style decompositions of arithmetic gates #1011

Closed tanujkhattar closed 4 months ago

tanujkhattar commented 4 months ago

All calls to context.qubit_manager.qalloc should be followed by calls to context.qubit_manager.qfree. Many arithmetic gate decompositions do not free the allocated qubits. This is bad and should be fixed.

[ ] There's no qfree call in entire comparison file - https://github.com/quantumlib/Qualtran/blob/main/qualtran/bloqs/arithmetic/comparison.py