Drive Shaping Methods

A quantum program in the Rydberg analog model is defined as a time-dependent drive Hamiltonian that is imposed on the qubits (in addition to the interaction Hamiltonian). The drive shaping configuration part (the drive_shaping field of SolverConfig) defines how the drive parameters are constructed.

In this notebook, we show how to use different drive shaping methods:

• HEURISTIC (Has no parameters to be customized).
• OPTIMIZED (Has seven parameters that can be customized).

We choose the method when defining the SolverConfig configuration, with drive_shaping_method = DriveType.(method)

Default SolverConfig parameters to run a quantum approach:

• use_quantum: bool = False (for using the drive shaping methods, we have to set it to True.)
• backend: LocalEmulator | RemoteEmulator | QPU (by default, use a LocalEmulator based on qutip)
• device: Device = DigitalAnalogDevice() (also available: AnalogDevice())
• embedding_method: str | EmbedderType | None = EmbedderType.GREEDY (also available: BLADE)
• drive_shaping_method: str | DriveType | None = DriveType.HEURISTIC (also available: OPTIMIZED)

In [ ]:

import torch

from qubosolver.qubo_instance import QUBOInstance
from qubosolver.config import SolverConfig, DriveShapingConfig
from qubosolver.qubo_types import DriveType
from qubosolver.solver import QuboSolver

import matplotlib.pyplot as plt
plt.rcParams["animation.html"] = "jshtml"

%matplotlib inline

---------------------------------------------------------------------------
KeyboardInterrupt                         Traceback (most recent call last)
Cell In[1], line 3
      1 import torch
----> 3 from qubosolver.qubo_instance import QUBOInstance
      4 from qubosolver.config import SolverConfig, DriveShapingConfig
      5 from qubosolver.qubo_types import DriveType

File ~/qubo-solver/qubosolver/__init__.py:5
      1 from __future__ import annotations
      3 from importlib import import_module
----> 5 from .data import *  # noqa: F403
      6 from .qubo_instance import *  # noqa: F403
      7 from .qubo_types import *  # noqa: F403

File ~/qubo-solver/qubosolver/data.py:10
      7 from torch.utils.data import Dataset
      9 from qubosolver.data_utils import generate_symmetric_mask
---> 10 from qubosolver.qubo_types import SolutionStatusType
     12 if TYPE_CHECKING:
     13     pass

File ~/qubo-solver/qubosolver/qubo_types.py:5
      1 from __future__ import annotations
      3 from enum import Enum
----> 5 from pulser.register.special_layouts import SquareLatticeLayout, TriangularLatticeLayout
      8 class StrEnum(str, Enum):
      9     """String-based Enums class implementation"""

File ~/.local/share/hatch/env/virtual/qubo-solver/IwRVwNQb/qubo-solver/lib/python3.10/site-packages/pulser/__init__.py:18
     15 """A pulse-level composer for neutral-atom quantum devices."""
     17 from pulser._version import __version__ as __version__
---> 18 from pulser.waveforms import (
     19     CompositeWaveform,
     20     CustomWaveform,
     21     ConstantWaveform,
     22     RampWaveform,
     23     BlackmanWaveform,
     24     InterpolatedWaveform,
     25     KaiserWaveform,
     26 )
     27 from pulser.pulse import Pulse
     28 from pulser.register import Register, Register3D

File ~/.local/share/hatch/env/virtual/qubo-solver/IwRVwNQb/qubo-solver/lib/python3.10/site-packages/pulser/waveforms.py:28
     25 from types import FunctionType
     26 from typing import TYPE_CHECKING, Any, Optional, Tuple, TypeVar, Union, cast
---> 28 import matplotlib.pyplot as plt
     29 import numpy as np
     30 import scipy.interpolate as interpolate

File ~/.local/share/hatch/env/virtual/qubo-solver/IwRVwNQb/qubo-solver/lib/python3.10/site-packages/matplotlib/pyplot.py:69
     66 from matplotlib import _docstring
     67 from matplotlib.backend_bases import (
     68     FigureCanvasBase, FigureManagerBase, MouseButton)
---> 69 from matplotlib.figure import Figure, FigureBase, figaspect
     70 from matplotlib.gridspec import GridSpec, SubplotSpec
     71 from matplotlib import rcsetup, rcParamsDefault, rcParamsOrig

File ~/.local/share/hatch/env/virtual/qubo-solver/IwRVwNQb/qubo-solver/lib/python3.10/site-packages/matplotlib/figure.py:40
     37 import numpy as np
     39 import matplotlib as mpl
---> 40 from matplotlib import _blocking_input, backend_bases, _docstring, projections
     41 from matplotlib.artist import (
     42     Artist, allow_rasterization, _finalize_rasterization)
     43 from matplotlib.backend_bases import (
     44     DrawEvent, FigureCanvasBase, NonGuiException, MouseButton, _get_renderer)

File ~/.local/share/hatch/env/virtual/qubo-solver/IwRVwNQb/qubo-solver/lib/python3.10/site-packages/matplotlib/projections/__init__.py:55
      1 """
      2 Non-separable transforms that map from data space to screen space.
      3 
   (...)
     52 `matplotlib.projections.polar` may also be of interest.
     53 """
---> 55 from .. import axes, _docstring
     56 from .geo import AitoffAxes, HammerAxes, LambertAxes, MollweideAxes
     57 from .polar import PolarAxes

File ~/.local/share/hatch/env/virtual/qubo-solver/IwRVwNQb/qubo-solver/lib/python3.10/site-packages/matplotlib/axes/__init__.py:1
----> 1 from . import _base
      2 from ._axes import Axes
      4 # Backcompat.

File <frozen importlib._bootstrap>:1027, in _find_and_load(name, import_)

File <frozen importlib._bootstrap>:1006, in _find_and_load_unlocked(name, import_)

File <frozen importlib._bootstrap>:688, in _load_unlocked(spec)

File <frozen importlib._bootstrap_external>:879, in exec_module(self, module)

File <frozen importlib._bootstrap_external>:975, in get_code(self, fullname)

File <frozen importlib._bootstrap_external>:1070, in get_data(self, path)

KeyboardInterrupt: 

** Create the QUBOInstance **

Here, we have a 3x3 QUBO matrix with negative diagonal and positive off-diagonal terms.

In [ ]:

coefficients = torch.tensor([[-1.0, 0.5, 0.2], [0.5, -2.0, 0.3], [0.2, 0.3, -3.0]])
instance = QUBOInstance(coefficients)

Heuristic Drive Shaper

Default method

In [ ]:

import torch

from qubosolver.qubo_instance import QUBOInstance
from qubosolver.config import EmbeddingConfig, LocalEmulator

from pulser_simulation import QutipBackendV2


def best_from_solution(sol):
    # sol.costs: tensor([..]) ; sol.bitstrings: tensor([[..],..])
    if sol.costs is None or len(sol.costs) == 0:
        return None, None
    idx = int(torch.argmin(sol.costs).item())
    best_cost = float(sol.costs[idx].item())
    best_bitstring = sol.bitstrings[idx].tolist()
    return best_cost, best_bitstring


def run_one(method: DriveType, q: torch.Tensor, runs: int = 500, dmm: bool = True):
    instance = QUBOInstance(coefficients=q)

    embed_cfg = EmbeddingConfig(
        embedding_method="greedy",
        greedy_traps=6,
        # pas de greedy_spacing => default
    )

    drive_cfg = DriveShapingConfig(
        drive_shaping_method=method,
        dmm=dmm,
    )

    backend = LocalEmulator(backend_type=QutipBackendV2, runs=runs)

    config = SolverConfig(
        use_quantum=True,
        embedding=embed_cfg,
        drive_shaping=drive_cfg,
        backend=backend,
    )

    solver = QuboSolver(instance, config)

    # solve (inclut exécution + mesure)
    sol = solver.solve()

    # afficher la séquence
    embedding = solver.embedding()
    drive = solver.drive(embedding)[0]
    solver.draw_sequence(drive, embedding)

    best_cost, best_bitstring = best_from_solution(sol)

    tag = "HEURISTIC"
    print("\n" + "=" * 80)
    print(f"[{tag}] runs={runs}")
    print("Solution object:")
    print(sol)
    print(f"Best sampled cost: {best_cost}")
    print(f"Best sampled bitstring: {best_bitstring}")

    return sol, best_cost, best_bitstring


if __name__ == "__main__":
    Q1 = torch.tensor([
        [-6.0,  2.0,  2.0,  2.0],
        [ 2.0, -7.5,  2.0,  2.0],
        [ 2.0,  2.0, -7.5,  2.0],
        [ 2.0,  2.0,  2.0, -7.0],
    ])

    sol_h_dmm, best_h_dmm, bs_h_dmm = run_one(DriveType.HEURISTIC, Q1, runs=500, dmm=True)
    sol_h_nodmm, best_h_nodmm, bs_h_nodmm = run_one(DriveType.HEURISTIC, Q1, runs=500, dmm=False)

    print("\n" + "#" * 80)
    print("COMPARISON (best sampled cost):")
    print(f"HEURISTIC (dmm=True) : {best_h_dmm}  bitstring={bs_h_dmm}")
    print(f"HEURISTIC (dmm=False): {best_h_nodmm}  bitstring={bs_h_nodmm}")

================================================================================
[ADIABATIC] runs=500
Solution object:
QUBOSolution(bitstrings=tensor([[0, 0, 1, 0],
        [0, 1, 0, 0],
        [0, 0, 0, 1],
        [1, 0, 0, 0],
        [0, 0, 0, 0]], dtype=torch.int32), costs=tensor([-7.5000, -7.5000, -7.0000, -6.0000,  0.0000]), counts=tensor([146, 148, 136,  64,   6]), probabilities=tensor([0.2920, 0.2960, 0.2720, 0.1280, 0.0120]), solution_status=<SolutionStatusType.UNPROCESSED: 'unprocessed'>)
Best sampled cost: -7.5
Best sampled bitstring: [0, 0, 1, 0]

================================================================================
[HEURISTIC (dmm=True)] runs=500
Solution object:
QUBOSolution(bitstrings=tensor([[0, 1, 1, 0],
        [0, 0, 1, 0],
        [0, 1, 0, 0],
        [0, 0, 0, 1],
        [1, 0, 0, 0],
        [0, 0, 0, 0]], dtype=torch.int32), costs=tensor([-11.0000,  -7.5000,  -7.5000,  -7.0000,  -6.0000,   0.0000]), counts=tensor([422,  33,  29,   4,   8,   4]), probabilities=tensor([0.8440, 0.0660, 0.0580, 0.0080, 0.0160, 0.0080]), solution_status=<SolutionStatusType.UNPROCESSED: 'unprocessed'>)
Best sampled cost: -11.0
Best sampled bitstring: [0, 1, 1, 0]

================================================================================
[HEURISTIC (dmm=False)] runs=500
Solution object:
QUBOSolution(bitstrings=tensor([[0, 1, 1, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 0, 1],
        [1, 0, 0, 0],
        [0, 0, 0, 0]], dtype=torch.int32), costs=tensor([-11.0000,  -7.5000,  -7.5000,  -7.0000,  -6.0000,   0.0000]), counts=tensor([337,  72,   8,  76,   5,   2]), probabilities=tensor([0.6740, 0.1440, 0.0160, 0.1520, 0.0100, 0.0040]), solution_status=<SolutionStatusType.UNPROCESSED: 'unprocessed'>)
Best sampled cost: -11.0
Best sampled bitstring: [0, 1, 1, 0]

################################################################################
COMPARISON (best sampled cost):
ADIABATIC            : -7.5  bitstring=[0, 0, 1, 0]
HEURISTIC (dmm=True) : -11.0  bitstring=[0, 1, 1, 0]
HEURISTIC (dmm=False): -11.0  bitstring=[0, 1, 1, 0]

Optimized Drive shaping

Parameters to customize:

For the OPTIMIZED drive shaping, we have the following parameters:

• optimized_n_calls: Number of calls for the optimization process.
• optimized_re_execute_opt_drive: Whether to re-run the optimal drive sequence after optimization.
• optimized_initial_omega_parameters: Default initial omega parameters for the drive. Defaults to (1, 2, 1).
• optimized_initial_detuning_parameters: Default initial detuning parameters for the drive. Defaults to (-2, 0, 2).

Default configuration

In [ ]:

default_config = SolverConfig.from_kwargs(
    use_quantum=True, drive_shaping=DriveShapingConfig(drive_shaping_method=DriveType.OPTIMIZED),
)
solver = QuboSolver(instance, default_config)

solution = solver.solve()
print(solution)

Changing optimized_n_calls

In [ ]:

default_config = SolverConfig.from_kwargs(
    use_quantum=True, drive_shaping=DriveShapingConfig(drive_shaping_method=DriveType.OPTIMIZED, optimized_n_calls=13),
)
solver = QuboSolver(instance, default_config)

solution = solver.solve()
print(solution)

Changing the initial parameters

Initial parameters of the optimization procedure can be changed as optimized_initial_omega_parameters and optimized_initial_detuning_parameters

In [ ]:

default_config = SolverConfig.from_kwargs(
    use_quantum=True, drive_shaping=DriveShapingConfig(drive_shaping_method=DriveType.OPTIMIZED, optimized_initial_omega_parameters=[1.0, 3.0, 1.0,], optimized_initial_detuning_parameters=[-9.0, 0.0, 5.0]),
)
solver = QuboSolver(instance, default_config)

solution = solver.solve()
print(solution)

Changing optimized_re_execute_opt_drive

In [ ]:

default_config = SolverConfig.from_kwargs(
    use_quantum=True, drive_shaping=DriveShapingConfig(drive_shaping_method=DriveType.OPTIMIZED, optimized_re_execute_opt_drive=True),
)
solver = QuboSolver(instance, default_config)

solution = solver.solve()
print(solution)

Adding custom functions

One can change the drive shaping method by incorporating custom functions for:

• Evaluating a candidate bitstring and QUBO via optimized_custom_qubo_cost
• Performing optimization with a different objective than the best cost via optimized_custom_objective
• Adding callback functions via optimized_callback_objective.

In [ ]:

from qubosolver.utils.qubo_eval import calculate_qubo_cost

# example of penalization
def penalized_qubo(bitstring: str, QUBO: torch.Tensor) -> float:
    return calculate_qubo_cost(bitstring, QUBO) + 2 * bitstring.count("0")

# example of saving intermediate results
opt_results = list()
def callback(d: dict) -> None:
    opt_results.append(d)

# example of using an average cost
def average_ojective(
    bitstrings: list,
    counts: list,
    probabilities: list,
    costs: list,
    best_cost: float,
    best_bitstring: str,
) -> float:
    return sum([p * c for p, c in zip(probabilities, costs)])

drive_shaping=DriveShapingConfig(drive_shaping_method=DriveType.OPTIMIZED,
    optimized_re_execute_opt_drive=True,
    optimized_custom_qubo_cost=penalized_qubo,
    optimized_callback_objective=callback,
    optimized_custom_objective = average_ojective,
)

config = SolverConfig(
    use_quantum=True,
    drive_shaping=drive_shaping,
)

In [ ]:

solver = QuboSolver(instance, config)
solution = solver.solve()
len(opt_results), opt_results[-1]

In [ ]:

solution