Source code for cirq.ops.gate_operation

# Copyright 2018 The Cirq Developers
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.

"""Basic types defining qubits, gates, and operations."""
import re
from typing import (Any, Dict, FrozenSet, List, Optional, Sequence, Tuple,
                    TypeVar, Union, TYPE_CHECKING)

import numpy as np

from cirq import protocols, value
from cirq.ops import raw_types, gate_features
from cirq.type_workarounds import NotImplementedType

    import cirq

[docs]@value.value_equality(approximate=True) class GateOperation(raw_types.Operation): """An application of a gate to a sequence of qubits."""
[docs] def __init__(self, gate: 'cirq.Gate', qubits: Sequence['cirq.Qid']) -> None: """ Args: gate: The gate to apply. qubits: The qubits to operate on. """ gate.validate_args(qubits) self._gate = gate self._qubits = tuple(qubits)
@property def gate(self) -> 'cirq.Gate': """The gate applied by the operation.""" return self._gate @property def qubits(self) -> Tuple['cirq.Qid', ...]: """The qubits targeted by the operation.""" return self._qubits def with_qubits(self, *new_qubits: 'cirq.Qid') -> 'cirq.Operation': return self.gate.on(*new_qubits) def with_gate(self, new_gate: 'cirq.Gate') -> 'cirq.Operation': return new_gate.on(*self.qubits) def __repr__(self): if hasattr(self.gate, '_op_repr_'): result = self.gate._op_repr_(self.qubits) if result is not None and result is not NotImplemented: return result gate_repr = repr(self.gate) qubit_args_repr = ', '.join(repr(q) for q in self.qubits) assert type(self.gate).__call__ == raw_types.Gate.__call__ # Abbreviate when possible. dont_need_on = re.match(r'^[a-zA-Z0-9.()]+$', gate_repr) if dont_need_on and self == self.gate.__call__(*self.qubits): return f'{gate_repr}({qubit_args_repr})' if self == self.gate.on(*self.qubits): return f'{gate_repr}.on({qubit_args_repr})' return (f'cirq.GateOperation(gate={self.gate!r}, ' f'qubits=[{qubit_args_repr}])') def __str__(self) -> str: qubits = ', '.join(str(e) for e in self.qubits) return f'{self.gate}({qubits})' def _json_dict_(self) -> Dict[str, Any]: return protocols.obj_to_dict_helper(self, ['gate', 'qubits']) def _group_interchangeable_qubits( self ) -> Tuple[Union['cirq.Qid', Tuple[int, FrozenSet['cirq.Qid']]], ...]: if not isinstance(self.gate, gate_features.InterchangeableQubitsGate): return self.qubits groups: Dict[int, List['cirq.Qid']] = {} for i, q in enumerate(self.qubits): k = self.gate.qubit_index_to_equivalence_group_key(i) if k not in groups: groups[k] = [] groups[k].append(q) return tuple(sorted((k, frozenset(v)) for k, v in groups.items())) def _value_equality_values_(self): return self.gate, self._group_interchangeable_qubits() def _qid_shape_(self): return protocols.qid_shape(self.gate) def _num_qubits_(self): return len(self._qubits) def _decompose_(self) -> 'cirq.OP_TREE': return protocols.decompose_once_with_qubits(self.gate, self.qubits, NotImplemented) def _pauli_expansion_(self) -> value.LinearDict[str]: return protocols.pauli_expansion(self.gate) def _apply_unitary_(self, args: 'protocols.ApplyUnitaryArgs' ) -> Union[np.ndarray, None, NotImplementedType]: return protocols.apply_unitary(self.gate, args, default=None) def _has_unitary_(self) -> bool: return protocols.has_unitary(self.gate) def _unitary_(self) -> Union[np.ndarray, NotImplementedType]: return protocols.unitary(self.gate, default=None) def _commutes_(self, other: Any, atol: float) -> Union[bool, NotImplementedType, None]: return self.gate._commutes_on_qids_(self.qubits, other, atol=atol) def _has_mixture_(self) -> bool: return protocols.has_mixture(self.gate) def _mixture_(self) -> Sequence[Tuple[float, Any]]: return protocols.mixture(self.gate, NotImplemented) def _has_channel_(self) -> bool: return protocols.has_channel(self.gate) def _channel_(self) -> Union[Tuple[np.ndarray], NotImplementedType]: return, NotImplemented) def _measurement_key_(self) -> str: return protocols.measurement_key(self.gate, NotImplemented) def _is_parameterized_(self) -> bool: return protocols.is_parameterized(self.gate) def _resolve_parameters_(self, resolver): resolved_gate = protocols.resolve_parameters(self.gate, resolver) return GateOperation(resolved_gate, self._qubits) def _circuit_diagram_info_(self, args: 'cirq.CircuitDiagramInfoArgs' ) -> 'cirq.CircuitDiagramInfo': return protocols.circuit_diagram_info(self.gate, args, NotImplemented) def _decompose_into_clifford_(self): sub = getattr(self.gate, '_decompose_into_clifford_with_qubits_', None) if sub is None: return NotImplemented return sub(self.qubits) def _trace_distance_bound_(self) -> float: return protocols.trace_distance_bound(self.gate) def _phase_by_(self, phase_turns: float, qubit_index: int) -> 'GateOperation': phased_gate = protocols.phase_by(self.gate, phase_turns, qubit_index, default=None) if phased_gate is None: return NotImplemented return GateOperation(phased_gate, self._qubits) def __pow__(self, exponent: Any) -> 'cirq.Operation': """Raise gate to a power, then reapply to the same qubits. Only works if the gate implements cirq.ExtrapolatableEffect. For extrapolatable gate G this means the following two are equivalent: (G ** 1.5)(qubit) or G(qubit) ** 1.5 Args: exponent: The amount to scale the gate's effect by. Returns: A new operation on the same qubits with the scaled gate. """ new_gate = protocols.pow(self.gate, exponent, NotImplemented) if new_gate is NotImplemented: return NotImplemented return self.with_gate(new_gate) def __mul__(self, other: Any) -> Any: result = self.gate._mul_with_qubits(self._qubits, other) # python will not auto-attempt the reverse order for same type. if result is NotImplemented and isinstance(other, GateOperation): return other.__rmul__(self) return result def __rmul__(self, other: Any) -> Any: return self.gate._rmul_with_qubits(self._qubits, other) def _qasm_(self, args: 'protocols.QasmArgs') -> Optional[str]: return protocols.qasm(self.gate, args=args, qubits=self.qubits, default=None) def _equal_up_to_global_phase_(self, other: Any, atol: Union[int, float] = 1e-8 ) -> Union[NotImplementedType, bool]: if not isinstance(other, type(self)): return NotImplemented if self.qubits != other.qubits: return False return protocols.equal_up_to_global_phase(self.gate, other.gate, atol=atol)
TV = TypeVar('TV', bound=raw_types.Gate)