Pre-processing

Quickstart: Solving a QUBO with Preprocessing and Tabu Search¶

This tutorial shows how to solve a simple QUBO problem using Tabu Search, with preprocessing enabled to reduce the problem size beforehand.

In [ ]:

Copied!





from qubosolver import QUBOInstance
from qubosolver.config import SolverConfig
from qubosolver.solver import QuboSolver

qubo = QUBOInstance(coefficients=[[-2.0, 1.0], [1.0, -2.0]])
config = SolverConfig.from_kwargs(do_preprocessing = True, use_quantum = False, classical_solver_type="dwave_sa")

solver = QuboSolver(qubo, config)
solution = solver.solve()
print(solution)
from qubosolver import QUBOInstance
from qubosolver.config import SolverConfig
from qubosolver.solver import QuboSolver

qubo = QUBOInstance(coefficients=[[-2.0, 1.0], [1.0, -2.0]])
config = SolverConfig.from_kwargs(do_preprocessing = True, use_quantum = False, classical_solver_type="dwave_sa")

solver = QuboSolver(qubo, config)
solution = solver.solve()
print(solution)

QUBOSolution(bitstrings=tensor([[1., 1.]]), costs=tensor([-2.]), counts=None, probabilities=None, solution_status=<SolutionStatusType.PREPROCESSED: 'preprocessed'>)

We can access the number of variables fixed by preprocessing via the attribute n_fixed_variables_preprocessing from the solver: