改成shape后断言正确,但是又报错,找不到索引:i = torch.sigmoid(torch.matmul(x, self.W_i_forward) + torch.matmul(h_forward_new[-1], self.U_i_forward) + self.b_i_forward) IndexError: index -1 is out of bounds for axis 0 with size 0
时间: 2024-03-03 17:51:09 浏览: 21
这个错误的原因是 `h_forward_new` 这个变量的长度为0,因此无法使用索引 -1 来获取最后一个元素。你需要确保在使用 `h_forward_new` 变量之前,它已经被正确地初始化了。另外,你还需要检查代码的逻辑是否正确,比如在某些情况下,`h_forward_new` 可能会为空,这时你需要特判处理。
另外,你可以使用 `print()` 函数来输出 `h_forward_new` 的长度或形状,以便更好地理解代码的执行过程,例如:
```python
print("h_forward_new:", h_forward_new.shape)
```
这样就可以查看 `h_forward_new` 的长度或形状了,从而更好地理解和调试代码。
相关问题
def forward(self, x): x = self.pool1(torch.sigmoid(self.conv1(x))) x = self.pool2(torch.sigmoid(self.conv2(x))) x = x.view(-1, 16 * 4 * 4) x = torch.sigmoid(self.fc1(x)) x = torch.sigmoid(self.fc2(x)) x = self.fc3(x) return xdef forward(self, x): x = self.pool1(torch.sigmoid(self.conv1(x))) x = self.pool2(torch.sigmoid(self.conv2(x))) x = x.view(-1, 16 * 4 * 4) x = torch.sigmoid(self.fc1(x)) x = torch.sigmoid(self.fc2(x)) x = self.fc3(x) return xdef forward(self, x): x = self.pool1(torch.sigmoid(self.conv1(x))) x = self.pool2(torch.sigmoid(self.conv2(x))) x = x.view(-1, 16 * 4 * 4) x = torch.sigmoid(self.fc1(x)) x = torch.sigmoid(self.fc2(x)) x = self.fc3(x) return xdef forward(self, x): x = self.pool1(torch.sigmoid(self.conv1(x))) x = self.pool2(torch.sigmoid(self.conv2(x))) x = x.view(-1, 16 * 4 * 4) x = torch.sigmoid(self.fc1(x)) x = torch.sigmoid(self.fc2(x)) x = self.fc3(x) return x
这是一个神经网络的前向传播函数,通常用于对输入数据进行预测或分类。该网络包括两个卷积层和三个全连接层,并使用了sigmoid激活函数和池化操作。具体来说,输入数据x经过conv1和pool1后,再经过conv2和pool2,最后通过多层全连接层生成输出。在全连接层中使用sigmoid激活函数,最后一层没有激活函数。
以下代码存在无法求导反向传播的bug,请你修改:# 反向LSTM input_backward = torch.flip(input, [0]) outputs_backward = [] for t in range(input_backward.size(0)): x = input_backward[t] i = torch.sigmoid(torch.matmul(x, self.W_i_backward) + torch.matmul(h_backward[-1], self.U_i_backward) + self.b_i_backward) f = torch.sigmoid(torch.matmul(x, self.W_f_backward) + torch.matmul(h_backward[-1], self.U_f_backward) + self.b_f_backward) c_tilde = torch.tanh(torch.matmul(x, self.W_c_backward) + torch.matmul(h_backward[-1], self.U_c_backward) + self.b_c_backward) c_backward[-1] = f * c_backward[-1] + i * c_tilde o = torch.matmul(x, self.W_o_backward) + torch.matmul(h_backward[-1], self.U_o_backward) + self.b_o_backward o = torch.sigmoid(o) h_backward[-1] = o * torch.tanh(c_backward[-1]) outputs_backward.append(h_backward[-1]) outputs_backward = torch.flip(torch.stack(outputs_backward), [0])
这段代码看起来没有明显的无法求导反向传播的 bug,但是如果存在问题的话可能是因为某些操作的输入没有进行 requires_grad=True 的设置。可以尝试添加以下代码,保证所有涉及到反向传播的张量都设置了 requires_grad=True:
```
input_backward.requires_grad_()
self.W_i_backward.requires_grad_()
self.U_i_backward.requires_grad_()
self.b_i_backward.requires_grad_()
self.W_f_backward.requires_grad_()
self.U_f_backward.requires_grad_()
self.b_f_backward.requires_grad_()
self.W_c_backward.requires_grad_()
self.U_c_backward.requires_grad_()
self.b_c_backward.requires_grad_()
self.W_o_backward.requires_grad_()
self.U_o_backward.requires_grad_()
self.b_o_backward.requires_grad_()
```
另外,如果在模型训练时发现该部分无法进行反向传播,可以尝试将该部分的代码放到 `torch.no_grad()` 中,避免该部分的梯度被累加。
```
with torch.no_grad():
input_backward = torch.flip(input, [0])
outputs_backward = []
for t in range(input_backward.size(0)):
x = input_backward[t]
i = torch.sigmoid(torch.matmul(x, self.W_i_backward) + torch.matmul(h_backward[-1], self.U_i_backward) + self.b_i_backward)
f = torch.sigmoid(torch.matmul(x, self.W_f_backward) + torch.matmul(h_backward[-1], self.U_f_backward) + self.b_f_backward)
c_tilde = torch.tanh(torch.matmul(x, self.W_c_backward) + torch.matmul(h_backward[-1], self.U_c_backward) + self.b_c_backward)
c_backward[-1] = f * c_backward[-1] + i * c_tilde
o = torch.matmul(x, self.W_o_backward) + torch.matmul(h_backward[-1], self.U_o_backward) + self.b_o_backward
o = torch.sigmoid(o)
h_backward[-1] = o * torch.tanh(c_backward[-1])
outputs_backward.append(h_backward[-1])
outputs_backward = torch.flip(torch.stack(outputs_backward), [0])
```