# This code is part of Qiskit.
# (C) Copyright IBM 2020, 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 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.
from abc import ABC, abstractmethod
from qiskit.opflow.operator_base import OperatorBase
from qiskit.utils.deprecation import deprecate_func
Deprecated: Converters take an Operator and return a new Operator, generally isomorphic
in some way with the first, but with certain desired properties. For example,
a converter may accept ``CircuitOp`` and return a ``SummedOp`` of
``PauliOps`` representing the circuit unitary. Converters may not
have polynomial space or time scaling in their operations. On the contrary, many
converters, such as a ``MatrixExpectation`` or ``MatrixEvolution``, which convert
``PauliOps`` to ``MatrixOps`` internally, will require time or space exponential
in the number of qubits unless a clever trick is known (such as the use of sparse
additional_msg="For code migration guidelines, visit https://qisk.it/opflow_migration.",
def __init__(self) -> None:
def convert(self, operator: OperatorBase) -> OperatorBase:
"""Accept the Operator and return the converted Operator
operator: The Operator to convert.
The converted Operator.