Source code for qiskit_aer.library.save_instructions.save_state

# 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 simulator state.
"""

from qiskit.circuit import QuantumCircuit
from .save_data import SaveSingleData
from ..default_qubits import default_qubits


[docs]class SaveState(SaveSingleData): """Save simulator state The format of the saved state depends on the simulation method used. """ def __init__(self, num_qubits, label=None, pershot=False, conditional=False): """Create new instruction to save the simualtor state. The format of the saved state depends on the simulation method used. Args: num_qubits (int): the number of qubits of the label (str or None): Optional, the key for retrieving saved data from results. If None the key will be the state type of the simulator. pershot (bool): if True save a list of states for each shot of the simulation rather than a single state [Default: False]. conditional (bool): if True save data conditional on the current classical register values [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. """ if label is None: label = "_method_" super().__init__("save_state", num_qubits, label, pershot=pershot, conditional=conditional)
[docs]def save_state(self, label=None, pershot=False, conditional=False): """Save the current simulator quantum state. Args: label (str or None): Optional, the key for retrieving saved data from results. If None the key will be the state type of the simulator. pershot (bool): if True save a list of statevectors for each shot of the simulation [Default: False]. conditional (bool): if True save pershot data conditional on the current classical register values [Default: False]. Returns: QuantumCircuit: with attached instruction. .. note: This instruction is always defined across all qubits in a circuit. """ qubits = default_qubits(self) instr = SaveState(len(qubits), label=label, pershot=pershot, conditional=conditional) return self.append(instr, qubits)
QuantumCircuit.save_state = save_state