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.
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#
#     https://www.apache.org/licenses/LICENSE-2.0
#
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"""Basic types defining qubits, gates, and operations."""

from typing import (
    Any,
    Dict,
    FrozenSet,
    List,
    Optional,
    Sequence,
    Tuple,
    Type,
    TypeVar,
    Union,
)

import numpy as np

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


[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: raw_types.Gate, qubits: Sequence[raw_types.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) -> raw_types.Gate: """The gate applied by the operation.""" return self._gate @property def qubits(self) -> Tuple[raw_types.Qid, ...]: """The qubits targeted by the operation.""" return self._qubits
[docs] def with_qubits(self, *new_qubits: raw_types.Qid) -> 'raw_types.Operation': return self.gate.on(*new_qubits)
[docs] def with_gate(self, new_gate: raw_types.Gate) -> 'raw_types.Operation': return new_gate.on(*self.qubits)
def __repr__(self): # Abbreviate when possible. if self == self.gate.on(*self.qubits): return '{!r}.on({})'.format( self.gate, ', '.join(repr(q) for q in self.qubits)) return 'cirq.GateOperation(gate={!r}, qubits={!r})'.format( self.gate, list(self.qubits)) def __str__(self): return '{}({})'.format(self.gate, ', '.join(str(e) for e in self.qubits)) def _json_dict_(self): return protocols.obj_to_dict_helper(self, ['gate', 'qubits']) def _group_interchangeable_qubits(self) -> Tuple[ Union[raw_types.Qid, Tuple[int, FrozenSet[raw_types.Qid]]], ...]: if not isinstance(self.gate, gate_features.InterchangeableQubitsGate): return self.qubits groups: Dict[int, List[raw_types.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) -> op_tree.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 _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 protocols.channel(self.gate, 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: 'protocols.CircuitDiagramInfoArgs' ) -> 'protocols.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) -> 'raw_types.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 _qasm_(self, args: 'protocols.QasmArgs') -> Optional[str]: return protocols.qasm(self.gate, args=args, qubits=self.qubits, default=None)
TV = TypeVar('TV', bound=raw_types.Gate)
[docs]@deprecated(deadline='v0.7.0', fix='use: `op.gate if isinstance(op.gate, gate_type) else None`') def op_gate_of_type(op: Any, gate_type: Type[TV]) -> Optional[TV]: """Returns gate of given type, if op has that gate otherwise None.""" gate = getattr(op, 'gate', None) return gate if isinstance(gate, gate_type) else None
@deprecated(deadline='v0.7.0', fix='use: `isinstance(op.gate, gate_type)`') def op_gate_isinstance(op: Any, gate_type: Type[TV]) -> bool: """Determines if op is a GateOperation with a gate of the given type.""" gate = getattr(op, 'gate', None) return isinstance(gate, gate_type)