方法一:基于随机采样和模拟退火的算法
算法思路:
代码示例:
import numpy as np
import matplotlib.pyplot as plt
from scipy.optimize import minimize
import math
# 生成不规则斑点
x = np.random.uniform(0, 100, 100)
y = np.random.uniform(0, 100, 100)
x_new = np.append(x, [10, 90, 10, 90])
y_new = np.append(y, [10, 10, 90, 90])
plt.scatter(x_new, y_new)
plt.show()
# 定义圆或椭圆的形状和位置,并计算其覆盖的点数
def count_points_in_circle(x, y, cx, cy, a, b):
d = np.sqrt((x-cx)**2/a**2 + (y-cy)**2/b**2)
count = np.sum(d<=1)
return count
# 定义目标函数
def f(x):
cx, cy, a, b = x
count = 0
for i in range(len(x_new)):
count += count_points_in_circle(x_new, y_new, cx, cy, a, b)
return -count
# 定义模拟退火算法
def simulated_annealing(cost_func, x0, N, T=10, alpha=0.9):
x = x0
cost = cost_func(x)
x_best = x
cost_best = cost
for i in range(N):
T *= alpha
x_new = np.random.normal(x, T, len(x))
cost_new = cost_func(x_new)
if cost_new > cost_best:
x_best = x_new
cost_best = cost_new
if cost_new >= cost:
x = x_new
cost = cost_new
else:
dE = cost_new - cost
p = np.exp(dE/T)
if np.random.random() < p:
x = x_new
cost = cost_new
return x_best, cost_best
# 运行模拟退火算法
x0 = [50, 50