使用matplotlib找最优权重w的画图问题

import numpy as np
import matplotlib.pyplot as plt

x_data = [1.0, 2.0, 3.0]
y_data = [2.0, 4.0, 6.0]

def forward(x):
return x * w

def loss(x, y):
y_pred = forward(x)
return (y_pred - y) * (y_pred - y)

w_list = []
mse_list = [] # mse 是平均平方误差
for w in np.arange(0.0, 4.1, 0.1):
print(‘w=’, w)
l_sum = 0
for x_val, y_val in zip(x_data, y_data): #zip 函数将x_data,y_data的数据以元组的形式显示出
来[(1.0, 2.0), (2.0, 3.0), (3.0, 4.0)]
y_pred_val = forward(x_val)
loss_val = loss(x_val, y_val)
l_sum += loss_val
print(’\t’, x_val, y_val, y_pred_val, loss_val)
print(‘MSE=’, l_sum / 3)
w_list.append(w)
mse_list.append(l_sum / 3)
plt.plot(w_list, mse_list)
plt.ylabel(‘Loss’)
plt.xlabel(‘w’)
plt.show()

结果显示：