Source code for cirq.ops.gate_features

# 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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"""Marker classes for indicating which additional features gates support.

For example: some gates are reversible, some have known matrices, etc.

import abc
from typing import Union, Iterable, Any, List

from cirq.ops import raw_types

[docs]class InterchangeableQubitsGate(metaclass=abc.ABCMeta): """Indicates operations should be equal under some qubit permutations."""
[docs] def qubit_index_to_equivalence_group_key(self, index: int) -> int: """Returns a key that differs between non-interchangeable qubits.""" return 0
[docs]class SingleQubitGate(raw_types.Gate, metaclass=abc.ABCMeta): """A gate that must be applied to exactly one qubit.""" def _num_qubits_(self) -> int: return 1
[docs] def on_each(self, *targets: Union[raw_types.Qid, Iterable[Any]] ) -> List[raw_types.Operation]: """Returns a list of operations apply this gate to each of the targets. Args: *targets: The qubits to apply this gate to. Returns: Operations applying this gate to the target qubits. Raises: ValueError if targets are not instances of Qid or List[Qid]. """ operations = [] # type: List[raw_types.Operation] for target in targets: if isinstance(target, Iterable) and not isinstance(target, str): operations.extend(self.on_each(*target)) elif isinstance(target, raw_types.Qid): operations.append(self.on(target)) else: raise ValueError( 'Gate was called with type different than Qid. Type: {}'. format(type(target))) return operations
[docs]class TwoQubitGate(raw_types.Gate, metaclass=abc.ABCMeta): """A gate that must be applied to exactly two qubits.""" def _num_qubits_(self) -> int: return 2
[docs]class ThreeQubitGate(raw_types.Gate, metaclass=abc.ABCMeta): """A gate that must be applied to exactly three qubits.""" def _num_qubits_(self) -> int: return 3