CPLEX

Solve a QUBO with CPLEX¶

Default CPLEX parameters:

• cplex_maxtime (float): 600.0
• cplex_log_path (str): "solver.log"
• do_preprocessing (bool): False
• do_postprocessing (bool): False

Note: Although preprocessing and postprocessing can be enabled, CPLEX is usually powerful enough to solve the QUBO sizes we handle without them.

In [ ]:

import torch
from qubosolver import QUBOInstance
from qubosolver.config import SolverConfig, ClassicalConfig
from qubosolver.solver import QuboSolver

coefficients = torch.load("qubo_size_15.pt")
instance = QUBOInstance(coefficients)

# Create a SolverConfig object with classical solver options.
cplex = ClassicalConfig(
    classical_solver_type="cplex",
    cplex_maxtime = 600.0, 
    cplex_log_path= "cplex.log"  
)
config = SolverConfig(
    classical=cplex,  
)
# Instantiate the qubo (classical) solver class.
classical_solver = QuboSolver(instance, config)

# Solve the QUBO problem and print the solution.
solution = classical_solver.solve()
print("Solution result:", solution)

import torch from qubosolver import QUBOInstance from qubosolver.config import SolverConfig, ClassicalConfig from qubosolver.solver import QuboSolver coefficients = torch.load("qubo_size_15.pt") instance = QUBOInstance(coefficients) # Create a SolverConfig object with classical solver options. cplex = ClassicalConfig( classical_solver_type="cplex", cplex_maxtime = 600.0, cplex_log_path= "cplex.log" ) config = SolverConfig( classical=cplex, ) # Instantiate the qubo (classical) solver class. classical_solver = QuboSolver(instance, config) # Solve the QUBO problem and print the solution. solution = classical_solver.solve() print("Solution result:", solution)

Solution result: QUBOSolution(bitstrings=tensor([[1., 0., 0., 0., 0., 1., 1., 0., 0., 0., 0., 1., 0., 1., 0.]]), costs=tensor([-273.9201]), counts=None, probabilities=None, solution_status=<SolutionStatusType.UNPROCESSED: 'unprocessed'>)