Allows decomposition of controlled 1x1 MatrixGate #7282
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- Resolved conflicts - Synced with latest upstream changes
daxfohl
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Apr 17, 2025
| # is set equal to the phase angle. | ||
| # Handle global phase gates by checking if the unitary is a 1x1 matrix with a global phase | ||
| unitary = protocols.unitary(self.sub_gate, default=None) | ||
| if ( |
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I was thinking this branch could be merged with the above branch. The conditions protocols.has_unitary(self.sub_gate) and self._qid_shape_() == (2,) * len(self._qid_shape_()) apply to both. The global phase inner branch would then just need an extra check for protocols.num_qubits(self.sub_gate) == 0. The if protocols.is_parameterized(self.sub_gate) or set(shape) != {2}: check can be removed, because parameterized gates fail has_unitary, and set(shape) == {2} is equivalent to the self_qid_shape_() condition. There's also no need for the three conditions you added, since zero qubits implies a 1x1 unitary, and the abs of a unitary must square-sum to 1 by definition.
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…aseGate (#7283) ## Summary Fixes #7248 This PR improves the decomposition logic for controlled gates in Cirq, ensuring that controlled 1x1 `MatrixGate` and `GlobalPhaseGate` instances decompose correctly. It also adds a targeted unit tests to verify this behavior. ## Details - Updated the [_decompose_with_context_](cci:1://file:///Users/revanthgundala/projects/Cirq/cirq-core/cirq/ops/controlled_gate.py:159:4-241:9) method in [cirq-core/cirq/ops/controlled_gate.py](cci:7://file:///Users/revanthgundala/projects/Cirq/cirq-core/cirq/ops/controlled_gate.py:0:0-0:0) to: - Correctly handle controlled gates with 1x1 unitary (global phase) by decomposing them into a `DiagonalGate` with the correct phase. - Added a parameterized test and additional explicit unit tests in [cirq-core/cirq/ops/controlled_gate_test.py](cci:7://file:///Users/revanthgundala/projects/Cirq/cirq-core/cirq/ops/controlled_gate_test.py:0:0-0:0) to: - Check that controlled global phase gates decompose to the correct diagonal structure for various phases and control configurations. Supersedes #7282 --------- Co-authored-by: Michael Hucka <mhucka@caltech.edu> Co-authored-by: Dax Fohl <dax.fohl@gmail.com> Co-authored-by: Pavol Juhas <juhas@google.com>
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…aseGate (quantumlib#7283) ## Summary Fixes quantumlib#7248 This PR improves the decomposition logic for controlled gates in Cirq, ensuring that controlled 1x1 `MatrixGate` and `GlobalPhaseGate` instances decompose correctly. It also adds a targeted unit tests to verify this behavior. ## Details - Updated the [_decompose_with_context_](cci:1://file:///Users/revanthgundala/projects/Cirq/cirq-core/cirq/ops/controlled_gate.py:159:4-241:9) method in [cirq-core/cirq/ops/controlled_gate.py](cci:7://file:///Users/revanthgundala/projects/Cirq/cirq-core/cirq/ops/controlled_gate.py:0:0-0:0) to: - Correctly handle controlled gates with 1x1 unitary (global phase) by decomposing them into a `DiagonalGate` with the correct phase. - Added a parameterized test and additional explicit unit tests in [cirq-core/cirq/ops/controlled_gate_test.py](cci:7://file:///Users/revanthgundala/projects/Cirq/cirq-core/cirq/ops/controlled_gate_test.py:0:0-0:0) to: - Check that controlled global phase gates decompose to the correct diagonal structure for various phases and control configurations. Supersedes quantumlib#7282 --------- Co-authored-by: Michael Hucka <mhucka@caltech.edu> Co-authored-by: Dax Fohl <dax.fohl@gmail.com> Co-authored-by: Pavol Juhas <juhas@google.com>
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Summary
Fixes #7248
This PR improves the decomposition logic for controlled gates in Cirq, ensuring that controlled 1x1
MatrixGateandGlobalPhaseGateinstances decompose correctly. It also adds a targeted unit test to verify the correct decomposition behavior.Details
DiagonalGatewith the correct phase.