Source code for qiskit_optimization.algorithms.qrao.rounding_common

# This code is part of a Qiskit project.
# (C) Copyright IBM 2023.
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.
"""Common classes for rounding schemes"""
from __future__ import annotations

from abc import ABC, abstractmethod
from dataclasses import dataclass

import numpy as np
from qiskit.circuit import QuantumCircuit

from qiskit_optimization.algorithms import SolutionSample

from .quantum_random_access_encoding import QuantumRandomAccessEncoding

[docs]@dataclass class RoundingResult: """Result of rounding""" expectation_values: list[complex] | None """Expectation values""" samples: list[SolutionSample] """List of samples after rounding""" bases: np.ndarray | None = None """The bases used for the magic rounding""" basis_shots: np.ndarray | None = None """The number of shots used for each basis for the magic rounding""" basis_counts: list[dict[str, int]] | None = None """The basis_counts represents the resulting counts obtained by measuring with the bases corresponding to the number of shots specified in basis_shots for the magic rounding."""
[docs]@dataclass class RoundingContext: """Information that is provided for rounding""" encoding: QuantumRandomAccessEncoding """Encoding containing the problem information.""" expectation_values: list[complex] | None """Expectation values for the relaxed Hamiltonian.""" circuit: QuantumCircuit | None = None """Circuit corresponding to the encoding and expectation values."""
[docs]class RoundingScheme(ABC): """Base class for a rounding scheme"""
[docs] @abstractmethod def round(self, rounding_context: RoundingContext) -> RoundingResult: """Perform rounding Returns: an instance of RoundingResult """