水を求めるミミズ

saleman.py

# -*- coding: utf-8 -*-

import numpy as np
import matplotlib.pyplot as plt

class TravelPoints():
    def __init__(self, num_points):
        self.points = np.ones((num_points, 2), dtype=np.float32)
        return
        
    def update(self, point_city, lr, var):
        index_nearest = np.argmin(np.linalg.norm(point_city - self.points, axis=1))
        self.points   = self.points + lr * self.coef_near(index_nearest, var).reshape(-1, 1) * (point_city - self.points)
        return

    def coef_near(self, index, var):
        indices = np.arange(-index, self.points.shape[0] - index)
        return np.exp(-(indices ** 2) / (2 * var ** 2))

points = TravelPoints(num_points=100)
cities = np.random.rand(20, 2)

for epoch in xrange(100):
    print epoch
    
    lr  = 0.2 * 0.99 ** epoch
    var = 1.5
        
    for city in cities:
        points.update(city, lr, var)
        plt.clf()
        plt.plot(cities[:,0], cities[:,1], 'bo')
        plt.plot(points.points[:,0], points.points[:,1], 'r')
        plt.pause(.001)