qiskit-aer/qiskit_aer/library/save_instructions/save_unitary.py

64 lines
2.1 KiB
Python

# This code is part of Qiskit.
#
# (C) Copyright IBM 2018, 2021.
#
# 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.
"""
Simulator instruction to save unitary matrix.
"""
from qiskit.circuit import QuantumCircuit
from .save_data import SaveSingleData
from ..default_qubits import default_qubits
class SaveUnitary(SaveSingleData):
"""Save Unitary"""
def __init__(self, num_qubits, label="unitary", pershot=False):
"""Create new instruction to save the unitary simulator state.
Args:
num_qubits (int): the number of qubits of the
label (str): the key for retrieving saved data from results.
pershot (bool): if True save a list of unitaries for each
shot of the simulation rather than a single
statevector [Default: False].
.. note::
This save instruction must always be performed on the full width of
qubits in a circuit, otherwise an exception will be raised during
simulation.
"""
super().__init__("save_unitary", num_qubits, label, pershot=pershot)
def save_unitary(self, label="unitary", pershot=False):
"""Save the current state of the unitary simulator.
Args:
label (str): the key for retrieving saved data from results.
pershot (bool): if True save a list of unitaries for each
shot of the simulation [Default: False].
Returns:
QuantumCircuit: with attached instruction.
.. note::
This instruction is always defined across all qubits in a circuit.
"""
qubits = default_qubits(self)
instr = SaveUnitary(len(qubits), label=label, pershot=pershot)
return self.append(instr, qubits)
QuantumCircuit.save_unitary = save_unitary