fig = plt.figure()
    ax = fig.add_axes(Axes3D(fig))
    ax.plot_surface(W, I, Z=MSE_data)

import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.mplot3d import Axes3D
class LinearModel:

    @staticmethod
    def forward(w, x):
        return w * x
    @staticmethod
    def forward_with_intercept(w, x, b):
        return w * x + b

    @staticmethod
    def get_loss(w, x, y_origin, exp=2, b=None):
        if b:
            y = LinearModel.forward_with_intercept(w, x, b)
        else:
            y = LinearModel.forward(w, x)
        return pow(y_origin - y, exp)
def test_2d():
    x_data = [1.0, 2.0, 3.0]
    y_data = [2.0, 4.0, 6.0]
    weight_data = []
    MSE_data = []

    # 設(shè)定實(shí)驗(yàn)的權(quán)重范圍
    for w in np.arange(0.0, 4.1, 0.1):
        weight_data.append(w)
        loss_total = 0
        # 計(jì)算每個(gè)權(quán)重在數(shù)據(jù)集上的MSE平均平方方差
        for x_val, y_val in zip(x_data, y_data):
            loss_total += LinearModel.get_loss(w, x_val, y_val)
        MSE_data.append(loss_total / len(x_data))

    # 繪圖
    plt.xlabel("weight")
    plt.ylabel("MSE")
    plt.plot(weight_data, MSE_data)
    plt.show()
def test_3d():
    x_data = [1.0, 2.0, 3.0]
    y_data = [5.0, 8.0, 11.0]
    weight_data = np.arange(0.0, 4.1, 0.1)
    intercept_data = np.arange(0.0, 4.1, 0.1)
    W, I = np.meshgrid(weight_data, intercept_data)

    MSE_data = []
    # 設(shè)定實(shí)驗(yàn)的權(quán)重范圍 循環(huán)要先寫截距的 meshgrid 的返回第二個(gè)是相當(dāng)于41*41 同一行值相同 ，要在第二層循環(huán)去遍歷權(quán)重
    for intercept in intercept_data:
        MSE_data_tmp = []
        for w in weight_data:
            loss_total = 0
            # 計(jì)算每個(gè)權(quán)重在數(shù)據(jù)集上的MSE平均平方方差
            for x_val, y_val in zip(x_data, y_data):
                loss_total += LinearModel.get_loss(w, x_val, y_val, b=intercept)
            MSE_data_tmp.append(loss_total / len(x_data))
        MSE_data.append(MSE_data_tmp)
    MSE_data = np.array(MSE_data)
    fig = plt.figure()
    ax = fig.add_axes(Axes3D(fig))
    ax.plot_surface(W, I, Z=MSE_data)
    plt.xlabel("weight")
    plt.ylabel("intercept")
    plt.show()
if __name__ == '__main__':
    test_2d()
    test_3d()