-
Notifications
You must be signed in to change notification settings - Fork 1k
/
parallel_gate.py
173 lines (131 loc) · 6.19 KB
/
parallel_gate.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
# Copyright 2021 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
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import AbstractSet, Union, Any, Optional, Tuple, TYPE_CHECKING, Dict
import numpy as np
from cirq import protocols, value
from cirq.ops import raw_types
from cirq.type_workarounds import NotImplementedType
if TYPE_CHECKING:
import cirq
from cirq.protocols.decompose_protocol import DecomposeResult
@value.value_equality
class ParallelGate(raw_types.Gate):
"""Augments existing gates to be applied on one or more groups of qubits."""
def __init__(self, sub_gate: 'cirq.Gate', num_copies: int) -> None:
"""Inits ParallelGate.
Args:
sub_gate: The gate to apply.
num_copies: Number of copies of the gate to apply in parallel.
Raises:
ValueError: If gate is not a single qubit gate or num_copies <= 0.
"""
if sub_gate.num_qubits() != 1:
# TODO: If needed, support for multi-qubit sub_gates can be
# added by updating the circuit diagram plotting logic.
raise ValueError("gate must be a single qubit gate")
if not num_copies > 0:
raise ValueError("gate must be applied at least once.")
self._sub_gate = sub_gate
self._num_copies = num_copies
def num_qubits(self) -> int:
return self.sub_gate.num_qubits() * self._num_copies
@property
def sub_gate(self) -> 'cirq.Gate':
return self._sub_gate
@property
def num_copies(self) -> int:
return self._num_copies
def _decompose_(self, qubits: Tuple['cirq.Qid', ...]) -> 'DecomposeResult':
if len(qubits) != self.num_qubits():
raise ValueError(f"len(qubits)={len(qubits)} should be {self.num_qubits()}")
step = self.sub_gate.num_qubits()
return [self.sub_gate(*qubits[i : i + step]) for i in range(0, len(qubits), step)]
def with_gate(self, sub_gate: 'cirq.Gate') -> 'ParallelGate':
"""ParallelGate with same number of copies but a new gate"""
return ParallelGate(sub_gate, self._num_copies)
def with_num_copies(self, num_copies: int) -> 'ParallelGate':
"""ParallelGate with same sub_gate but different num_copies"""
return ParallelGate(self.sub_gate, num_copies)
def __repr__(self) -> str:
return f'cirq.ParallelGate(sub_gate={self.sub_gate!r}, num_copies={self._num_copies})'
def __str__(self) -> str:
return f'{self.sub_gate} x {self._num_copies}'
def _value_equality_values_(self) -> Any:
return self.sub_gate, self._num_copies
def _has_unitary_(self) -> bool:
return protocols.has_unitary(self.sub_gate)
def _is_parameterized_(self) -> bool:
return protocols.is_parameterized(self.sub_gate)
def _parameter_names_(self) -> AbstractSet[str]:
return protocols.parameter_names(self.sub_gate)
def _resolve_parameters_(
self, resolver: 'cirq.ParamResolver', recursive: bool
) -> 'ParallelGate':
return self.with_gate(
sub_gate=protocols.resolve_parameters(self.sub_gate, resolver, recursive)
)
def _unitary_(self) -> Union[np.ndarray, NotImplementedType]:
# Obtain the unitary for the single qubit gate
single_unitary = protocols.unitary(self.sub_gate, NotImplemented)
# Make sure we actually have a matrix
if single_unitary is NotImplemented:
return single_unitary
# Create a unitary which corresponds to applying the gate
# unitary _num_copies times. This will blow up memory fast.
unitary = single_unitary
for _ in range(self._num_copies - 1):
unitary = np.kron(unitary, single_unitary)
return unitary
def _trace_distance_bound_(self) -> Optional[float]:
if protocols.is_parameterized(self.sub_gate):
return None
angle = self._num_copies * np.arcsin(protocols.trace_distance_bound(self.sub_gate))
if angle >= np.pi * 0.5:
return 1.0
return np.sin(angle)
def _circuit_diagram_info_(
self, args: 'cirq.CircuitDiagramInfoArgs'
) -> 'cirq.CircuitDiagramInfo':
diagram_info = protocols.circuit_diagram_info(self.sub_gate, args, NotImplemented)
if diagram_info == NotImplemented:
return diagram_info
# Include symbols for every qubit instead of just one.
wire_symbols = tuple(diagram_info.wire_symbols) * self._num_copies
return protocols.CircuitDiagramInfo(
wire_symbols=wire_symbols, exponent=diagram_info.exponent, connected=False
)
def __pow__(self, exponent: Any) -> 'ParallelGate':
"""Raises underlying gate to a power, applying same number of copies.
For extrapolatable gate G this means the following two are equivalent:
(G ** 1.5) x k or (G x k) ** 1.5
Args:
exponent: The amount to scale the gate's effect by.
Returns:
ParallelGate with same num_copies with the scaled underlying gate.
"""
new_gate = protocols.pow(self.sub_gate, exponent, NotImplemented)
if new_gate is NotImplemented:
return NotImplemented
return self.with_gate(new_gate)
def _json_dict_(self) -> Dict[str, Any]:
return protocols.obj_to_dict_helper(self, attribute_names=["sub_gate", "num_copies"])
def parallel_gate_op(gate: 'cirq.Gate', *targets: 'cirq.Qid') -> 'cirq.Operation':
"""Constructs a ParallelGate using gate and applies to all given qubits
Args:
gate: The gate to apply
*targets: The qubits on which the ParallelGate should be applied.
Returns:
ParallelGate(gate, len(targets)).on(*targets)
"""
return ParallelGate(gate, len(targets)).on(*targets)