"""This module contains the ``ExactSamplerSolver`` class."""
from __future__ import annotations
from typing import Any
from dimod import ExactSolver
from tno.quantum.optimization.qubo.components import QUBO, Solver
from tno.quantum.optimization.qubo.solvers._dwave._dimod_sample_set_result import (
DimodSampleSetResult,
)
from tno.quantum.optimization.qubo.solvers._dwave._utils import (
get_singleton,
)
[docs]class ExactSamplerSolver(Solver[DimodSampleSetResult]):
"""D-Wave exact sampler solver.
The :py:class:`ExactSamplerSolver` class solves QUBOs exactly using a brute force
search by the :py:class:`~dimod.reference.samplers.ExactSolver`.
Example:
>>> from tno.quantum.optimization.qubo.components import QUBO
>>> from tno.quantum.optimization.qubo.solvers import ExactSamplerSolver
>>>
>>> qubo = QUBO([[1, 2, 3], [4, -50, 6], [7, 8, 9]])
>>> solver = ExactSamplerSolver()
>>> result = solver.solve(qubo)
>>> result.best_bitvector
BitVector(010)
"""
[docs] def __init__(self, **sample_kwargs: Any) -> None:
"""Init :py:class:`ExactSamplerSolver`.
Args:
sample_kwargs: Additional keyword arguments that can be used for the
sampler. The :py:class:`~dimod.reference.samplers.ExactSolver` does not
take additional parameters.
"""
self.sampler = get_singleton(ExactSolver)
self.sample_kwargs = sample_kwargs
def _solve(self, qubo: QUBO) -> DimodSampleSetResult:
"""Solves the given QUBO using sample_qubo functionality of the ExactSolver."""
response = self.sampler.sample(qubo.to_bqm(), **self.sample_kwargs)
return DimodSampleSetResult.from_result(qubo, response)