tutorial3_max_cut.py

import numpy as np
import kaiwu as kw
kw.common.CheckpointManager.save_dir = "/tmp"
kw.license.init(user_id="xxxxxx", sdk_code="xxxxxxxx")
# Import the plotting library
import matplotlib.pyplot as plt
# invert input graph matrix
matrix = -np.array([
                [0, 1, 0, 1, 1, 0, 0, 1, 1, 0],
                [1, 0, 1, 0, 0, 1, 1, 1, 0, 0],
                [0, 1, 0, 1, 1, 0, 0, 0, 1, 0],
                [1, 0, 1, 0, 0, 1, 1, 0 ,1, 0],
                [1, 0, 1, 0, 0, 1, 0, 1, 0, 1],
                [0, 1, 0, 1, 1, 0, 0, 0, 1, 1],
                [0, 1, 0, 1, 0, 0, 0, 0, 0, 1],
                [1, 1, 0, 0, 1, 0, 0, 0, 1, 0],
                [1, 0, 1, 1, 0, 1, 0, 1, 0, 1],
                [0, 0, 0, 0, 1, 1, 1, 0, 1, 0]])
               
worker = kw.classical.SimulatedAnnealingOptimizer(initial_temperature=100,
                                                  alpha=0.99,
                                                  cutoff_temperature=0.001,
                                                  iterations_per_t=10,
                                                  size_limit=100)
output = worker.solve(matrix)
opt = kw.sampler.optimal_sampler(matrix, output, 0)
best = opt[0][0]
max_cut = (np.sum(-matrix)-np.dot(-matrix,best).dot(best))/4
print("The obtained max cut is " + str(max_cut) + ".")