mirror of https://github.com/Qiskit/qiskit-aer.git
80 lines
3.0 KiB
Python
80 lines
3.0 KiB
Python
# This code is part of Qiskit.
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#
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# (C) Copyright IBM 2018, 2021.
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#
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# This code is licensed under the Apache License, Version 2.0. You may
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# obtain a copy of this license in the LICENSE.txt file in the root directory
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# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
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#
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# Any modifications or derivative works of this code must retain this
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# copyright notice, and modified files need to carry a notice indicating
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# that they have been altered from the originals.
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"""
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Simulator instruction to save simulator state.
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"""
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from qiskit.circuit import QuantumCircuit
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from .save_data import SaveSingleData
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from ..default_qubits import default_qubits
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class SaveState(SaveSingleData):
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"""Save simulator state
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The format of the saved state depends on the simulation method used.
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"""
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def __init__(self, num_qubits, label=None, pershot=False, conditional=False):
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"""Create new instruction to save the simualtor state.
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The format of the saved state depends on the simulation method used.
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Args:
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num_qubits (int): the number of qubits of the
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label (str or None): Optional, the key for retrieving saved data
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from results. If None the key will be the
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state type of the simulator.
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pershot (bool): if True save a list of states for each
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shot of the simulation rather than a single
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state [Default: False].
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conditional (bool): if True save data conditional on the current
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classical register values [Default: False].
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.. note::
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This save instruction must always be performed on the full width of
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qubits in a circuit, otherwise an exception will be raised during
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simulation.
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"""
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if label is None:
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label = "_method_"
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super().__init__("save_state", num_qubits, label, pershot=pershot, conditional=conditional)
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def save_state(self, label=None, pershot=False, conditional=False):
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"""Save the current simulator quantum state.
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Args:
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label (str or None): Optional, the key for retrieving saved data
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from results. If None the key will be the
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state type of the simulator.
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pershot (bool): if True save a list of statevectors for each
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shot of the simulation [Default: False].
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conditional (bool): if True save pershot data conditional on the
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current classical register values
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[Default: False].
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Returns:
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QuantumCircuit: with attached instruction.
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.. note:
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This instruction is always defined across all qubits in a circuit.
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"""
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qubits = default_qubits(self)
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instr = SaveState(len(qubits), label=label, pershot=pershot, conditional=conditional)
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return self.append(instr, qubits)
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QuantumCircuit.save_state = save_state
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