# 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 statevector.
"""
from qiskit.circuit import QuantumCircuit
from .save_data import SaveSingleData
from ..default_qubits import default_qubits
[docs]class SaveStatevector(SaveSingleData):
"""Save statevector"""
def __init__(self, num_qubits, label="statevector", pershot=False, conditional=False):
"""Create new instruction to save the simulator statevector.
Args:
num_qubits (int): the number of qubits
label (str): the key for retrieving saved data from results.
pershot (bool): if True save a list of statevectors for each
shot of the simulation rather than a single
statevector [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.
"""
super().__init__(
"save_statevector", num_qubits, label, pershot=pershot, conditional=conditional
)
[docs]class SaveStatevectorDict(SaveSingleData):
"""Save statevector as ket-form dictionary."""
def __init__(self, num_qubits, label="statevector_dict", pershot=False, conditional=False):
"""Create new instruction to save the simulator statevector as a dict.
Args:
num_qubits (int): the number of qubits
label (str): the key for retrieving saved data from results.
pershot (bool): if True save a list of statevectors for each
shot of the simulation rather than a single
statevector [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.
"""
super().__init__(
"save_statevector_dict", num_qubits, label, pershot=pershot, conditional=conditional
)
[docs]def save_statevector(self, label="statevector", pershot=False, conditional=False):
"""Save the current simulator quantum state as a statevector.
Args:
pershot (bool): if True save a list of statevectors for each
shot of the simulation [Default: False].
label (str): the key for retrieving saved data from results.
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 = SaveStatevector(len(qubits), label=label, pershot=pershot, conditional=conditional)
return self.append(instr, qubits)
[docs]def save_statevector_dict(self, label="statevector", pershot=False, conditional=False):
"""Save the current simulator quantum state as a statevector as a dict.
Args:
label (str): the key for retrieving saved data from results.
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 = SaveStatevectorDict(len(qubits), label=label, pershot=pershot, conditional=conditional)
return self.append(instr, qubits)
QuantumCircuit.save_statevector = save_statevector
QuantumCircuit.save_statevector_dict = save_statevector_dict