Source code for qiskit_algorithms.time_evolvers.pvqd.pvqd_result

# This code is part of a Qiskit project.
#
# (C) Copyright IBM 2022, 2024.
#
# 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 http://www.apache.org/licenses/LICENSE-2.0.
#
# 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.

"""Result object for p-VQD."""
from __future__ import annotations

from collections.abc import Sequence

import numpy as np
from qiskit.circuit import QuantumCircuit
from ..time_evolution_result import TimeEvolutionResult


class PVQDResult(TimeEvolutionResult):
    """The result object for the p-VQD algorithm."""

    # pylint: disable=too-many-positional-arguments
    def __init__(
        self,
        evolved_state: QuantumCircuit,
        aux_ops_evaluated: list[tuple[complex, complex]] | None = None,
        times: list[float] | None = None,
        parameters: list[np.ndarray] | None = None,
        fidelities: Sequence[float] | None = None,
        estimated_error: float | None = None,
        observables: list[list[float]] | None = None,
    ):
        """
        Args:
            evolved_state: An evolved quantum state.
            aux_ops_evaluated: Optional list of observables for which expected values on an evolved
                state are calculated. These values are in fact tuples formatted as (mean, standard
                deviation).
            times: The times evaluated during the time integration.
            parameters: The parameter values at each evaluation time.
            fidelities: The fidelity of the Trotter step and variational update at each iteration.
            estimated_error: The overall estimated error evaluated as one minus the
                product of all fidelities.
            observables: The value of the observables evaluated at each iteration.
        """
        super().__init__(evolved_state, aux_ops_evaluated)  # type: ignore[arg-type]
        self.times = times  # type: ignore[assignment]
        self.parameters = parameters
        self.fidelities = fidelities
        self.estimated_error = estimated_error
        self.observables = observables  # type: ignore[assignment]