plt 3d曲面图看极值

import numpy as np
import matplotlib.pyplot as plt

def himmelblau(x):
    # himmelblau 函数实现，传入参数 x 为 2 个元素的 List
    return (x[0] ** 2 + x[1] - 11) ** 2 + (x[0] + x[1] ** 2 - 7) ** 2

x = np.arange(-6, 6, 0.1) # 可视化的 x 坐标范围为-6~6
y = np.arange(-6, 6, 0.1)

print('x,y range:', x.shape, y.shape)
# 生成 x-y 平面采样网格点，方便可视化
X, Y = np.meshgrid(x, y)
print('X,Y maps:', X.shape, Y.shape)
Z = himmelblau([X, Y]) # 计算网格点上的函数值

x,y range: (120,) (120,)
X,Y maps: (120, 120) (120, 120)

from mpl_toolkits.mplot3d import Axes3D
# 绘制 himmelblau 函数曲面
fig = plt.figure('himmelblau')
ax = fig.gca(projection='3d') # 设置 3D 坐标轴
ax.plot_surface(X, Y, Z) # 3D 曲面图
ax.view_init(60, -30)
ax.set_xlabel('x')
ax.set_ylabel('y')
plt.show()