Source code for qlauncher.routines.cirq

 1"""
 2Routine file for Cirq library
 3"""
 4from typing import Literal
 5from collections.abc import Sequence
 6
 7import qiskit
 8from qiskit.primitives import Sampler
 9from qiskit.primitives.base.sampler_result import SamplerResult
10from qiskit.result import QuasiDistribution
11
12from qlauncher.base import Backend
13from qlauncher.base.translator import Translation
14from qlauncher.exceptions import DependencyError
15try:
16    import cirq
17    from cirq.sim.sparse_simulator import Simulator
18except ImportError as e:
19    raise DependencyError(e, install_hint='cirq') from e
20
21
22class _CirqRunner:
23    simulator = Simulator()
24    repetitions = 1024
25
26    @classmethod
27    def calculate_circuit(cls, circuit: qiskit.QuantumCircuit) -> dict:
28        circuit = circuit.measure_all(inplace=False)
29        cirq_circ = Translation.get_translation(circuit, 'cirq')
30        result = cls.simulator.run(cirq_circ, repetitions=cls.repetitions)
31        return cls._result_to_dist(result)
32
33    @classmethod
34    def _result_to_dist(cls, result) -> dict:
35        return cirq_result_to_probabilities(result)
36
37

[docs]
38class CirqSampler(Sampler):
39    """ Sampler adapter for Cirq """
40
41    def _call(self, circuits: Sequence[int], parameter_values: Sequence[Sequence[float]], **run_options) -> SamplerResult:
42        bound_circuits = []
43        for i, value in zip(circuits, parameter_values):
44            bound_circuits.append(
45                self._circuits[i]
46                if len(value) == 0
47                else self._circuits[i].assign_parameters(dict(zip(self._parameters[i], value)))
48            )
49        distributions = [_CirqRunner.calculate_circuit(circuit) for circuit in bound_circuits]
50        quasi_dists = list(map(QuasiDistribution, distributions))
51        return SamplerResult(quasi_dists, [{} for _ in range(len(parameter_values))])

52
53

[docs]
54class CirqBackend(Backend):
55    """
56
57    Args:
58        Backend (_type_): _description_
59    """
60
61    def __init__(self, name: Literal['local_simulator'] = 'local_simulator'):
62        self.sampler = self.samplerV1 = CirqSampler()
63        super().__init__(name)

64
65

[docs]
66def cirq_result_to_probabilities(
67    result: cirq.Result,
68    integer_keys: bool = False
69) -> dict:
70    measurements = result.measurements
71
72    sorted_keys = list(measurements.keys())
73
74    bitstrings = []
75    num_shots = len(measurements[sorted_keys[0]])
76
77    for shot_index in range(num_shots):
78        bits = []
79        for key in sorted_keys:
80            bits.extend(str(b) for b in measurements[key][shot_index])
81
82        bitstring = "".join(bits)
83        bitstrings.append(bitstring)
84
85    counts = {}
86    for bs in bitstrings:
87        counts[bs] = counts.get(bs, 0) + 1
88
89    total_shots = sum(counts.values())
90    if integer_keys:
91        prob_dict = {int(k, 2): v / total_shots for k, v in counts.items()}
92    else:
93        prob_dict = {k: v / total_shots for k, v in counts.items()}
94
95    return prob_dict