loss_history = nn.train(x, y, learning_rate, num_epochs) plt.plot(loss_history) plt.title('Loss') plt.xlabel('Epoch') plt.ylabel('MSE') plt.show()

这段代码的作用是使用神经网络模型nn对输入x和输出y进行训练，并记录每个epoch的损失值。然后，使用matplotlib库将每个epoch的损失值可视化出来。

具体来说，代码中的nn.train()函数会返回一个列表loss_history，其中包含了每个epoch的损失值。接着，使用plt.plot()函数将loss_history中的损失值绘制成一条曲线。然后，使用plt.title()、plt.xlabel()和plt.ylabel()函数分别设置图表的标题、x轴标签和y轴标签。最后，使用plt.show()函数将图表显示出来。这样，我们就可以通过观察损失曲线来判断模型的训练效果。

相关问题

def train(self, X, y, learning_rate, num_epochs): loss_history=[] for i in range(num_epochs): y_hat = self.forward(X) loss = np.mean(np.square(y_hat - y)) loss_history.append(loss) self.backward(X, y, learning_rate, num_epochs) if i % 100 == 0: print('Epoch', i, '- Loss:', loss) return loss_history # 加载数据 X = data.iloc[:, :-1].values y = data.iloc[:, -1:].values X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42) # 训练模型 input_dim=13 hidden_dim=25 output_dim=1 nn=NeuralNetwork(input_dim, hidden_dim, output_dim) learning_rate=0.05 num_epochs=2000 loss_history=nn.train(X, y, learning_rate, num_epochs) plt.plot(loss_history)b报错ypeError: NeuralNetwork.backward() takes 4 positional arguments but 5 were given

在你调用`NeuralNetwork.backward()`函数的时候，传入了5个参数`X, y, learning_rate, num_epochs`和函数本身的一个参数`self`。但是`NeuralNetwork.backward()`函数只需要4个参数，即`X, y, learning_rate, num_epochs`。

你可以将`num_epochs`这个参数从`NeuralNetwork.backward()`函数中删除，这样错误就可以被解决了。

修改后的代码如下所示：

def train(self, X, y, learning_rate, num_epochs):
    loss_history=[]
    for i in range(num_epochs):
        y_hat = self.forward(X)
        loss = np.mean(np.square(y_hat - y))
        loss_history.append(loss)
        self.backward(X, y, learning_rate)
        if i % 100 == 0:
            print('Epoch', i, '- Loss:', loss)
    return loss_history

# 加载数据
X = data.iloc[:, :-1].values
y = data.iloc[:, -1:].values
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)

# 训练模型
input_dim=13
hidden_dim=25
output_dim=1
nn=NeuralNetwork(input_dim, hidden_dim, output_dim)
learning_rate=0.05
num_epochs=2000
loss_history=nn.train(X, y, learning_rate, num_epochs)
plt.plot(loss_history)

希望能够帮到你！

X = data.iloc[:, :-1].values y = data.iloc[:, -1:].values X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42) # 训练模型 input_dim=13 hidden_dim=25 output_dim=1 nn=NeuralNetwork(input_dim, hidden_dim, output_dim) learning_rate=0.0016 num_epochs=2000 loss_history=nn.train(X, y, learning_rate, num_epochs) plt.plot(loss_history) plt.title('loss') plt.xlabel('Epoch') plt.ylabel('MSE')根据此代码写预测代码

# 预测代码
# 加载预测数据并进行预处理
data_pred = pd.read_excel(r'C:\Users\Lenovo\Desktop\data_pred.xlsx')
data_pred = data_pred.iloc[:, :-1].values
data_pred = (data_pred - np.mean(X_train, axis=0)) / np.std(X_train, axis=0)
# 进行预测
y_pred = nn.forward(data_pred)
y_pred = y_pred * np.std(y_train) + np.mean(y_train)
print(y_pred)