每日笔记-LSTM

今天,搞了一段代码,但没有达到应有的效果

import torch
import torch.nn as nn
import numpy as np

# 设置随机种子以便结果可重复
torch.manual_seed(42)

# 定义一个更复杂的LSTM模型
class ComplexLSTMModel(nn.Module):
    def __init__(self, input_size, hidden_size, output_size):
        super(ComplexLSTMModel, self).__init__()
        self.hidden_size = hidden_size
        self.lstm = nn.LSTM(input_size, hidden_size, num_layers=2)  # 增加了一个LSTM层
        self.fc = nn.Linear(hidden_size, output_size)

    def forward(self, input):
        lstm_out, _ = self.lstm(input.view(len(input), 1, -1))
        output = self.fc(lstm_out.view(len(input), -1))
        return output[-1]

# 准备数据
input_size = 1
hidden_size = 8  
output_size = 1
lr = 0.01
num_epochs = 100 

# 生成一些示例数据
data = np.sin(np.arange(0, 100, 0.1))

# 定义模型、损失函数和优化器
model = ComplexLSTMModel(input_size, hidden_size, output_size)
criterion = nn.MSELoss()
optimizer = torch.optim.Adam(model.parameters(), lr=lr)

# 训练模型
for epoch in range(num_epochs):    
    inputs = torch.Tensor(data[:-1]).view(-1, 1, 1)
    labels = torch.Tensor(data[1:])

    optimizer.zero_grad()
    outputs = model(inputs)

    loss = criterion(outputs, labels)
    loss.backward()
    optimizer.step()

    if (epoch+1) % 10 == 0:
        print(f'Epoch [{epoch+1}/{num_epochs}], Loss: {loss.item():.4f}')

# 预测
with torch.no_grad():
    future = 100
    # 用训练数据最后一个数据点开始预测
    pred_data = [data[-1]]
    for _ in range(future):
        inputs = torch.Tensor([pred_data[-1]]).view(-1, 1, 1)
        pred = model(inputs)
        pred_data.append(pred.item())

# 绘制结果
import matplotlib.pyplot as plt
plt.plot(data, label='Original data')
plt.plot(np.arange(len(data)-1, len(data) + future), pred_data, label='Predictions')
plt.legend()
plt.show()

　　结果如图:

 没有达到想象的效果

 

-----------------------------------

仔细阅读后，找到了问题症结所在。

修改后的代码：

import torch
import torch.nn as nn
import numpy as np

torch.manual_seed(42)

class LSTMModel(nn.Module):
    def __init__(self, input_size, hidden_size, output_size):
        super(LSTMModel, self).__init__()
        self.hidden_size = hidden_size
        self.lstm = nn.LSTM(input_size, hidden_size, num_layers=2) 
        self.fc = nn.Linear(hidden_size, output_size)        
    
    def forward(self, input):
        lstm_out, self.hidden = self.lstm(input.view(len(input), 1, -1))
        output = self.fc(lstm_out.view(len(input), -1))
        return output[-1]

input_size = 1
hidden_size = 16  
output_size = 1
lr = 0.001
num_epochs = 100

data = np.sin(np.arange(0, 100, 0.1))
# 制作训练数据
inputs = []
labels = [] 
for i in range(20, len(data)):
    inputs.append(data[i-20:i])
    labels.append(data[i])

model = LSTMModel(input_size, hidden_size, output_size)
criterion = nn.MSELoss()
optimizer = torch.optim.Adam(model.parameters(), lr=lr)

for epoch in range(num_epochs):
    for i in range(len(inputs) - 100):
        optimizer.zero_grad()
        outputs = model(torch.Tensor(inputs[i]).view(-1, 1, 1))
        loss = criterion(outputs, torch.Tensor([labels[i]]))
        loss.backward()        
        optimizer.step()

    if (epoch+1) % 1 == 0:
        print(f'Epoch [{epoch+1}/{num_epochs}], Loss: {loss.item():.6f}')

# 预测
pred_data = []
with torch.no_grad():
    for i in range(len(inputs) - 100, len(inputs)):        
        outputs = model(torch.Tensor(inputs[i]).view(-1, 1, 1))
        pred_data.append(outputs.item())
        
import matplotlib.pyplot as plt
plt.plot(data[:-100], label='Original data')
plt.plot(np.arange(len(data) - 100, len(data)), pred_data, label='Predictions')
plt.legend()
plt.show()

　　显示图像正常 ！