self.gradients = None
时间: 2023-07-06 17:07:31 浏览: 41
这是一个在神经网络中用于保存梯度的变量,通常在反向传播算法中使用。在神经网络的训练过程中,需要计算损失函数对于模型参数的梯度,然后使用这些梯度来更新模型参数,以使得模型的预测结果更加准确。在计算梯度时,需要把梯度值保存在这个变量中,以便在后续的更新步骤中使用。如果这个变量没有被正确设置或者被清空了,那么在进行模型参数更新时就会出现错误。
相关问题
def __init__(self, sess, state_dim, learning_rate): self.sess = sess self.s_dim = state_dim self.lr_rate = learning_rate # Create the critic network self.inputs, self.out = self.create_critic_network() # Get all network parameters self.network_params = \ tf.compat.v1.get_collection(tf.compat.v1.GraphKeys.TRAINABLE_VARIABLES, scope='critic') # Set all network parameters self.input_network_params = [] for param in self.network_params: self.input_network_params.append( tf.compat.v1.placeholder(tf.float32, shape=param.get_shape())) self.set_network_params_op = [] for idx, param in enumerate(self.input_network_params): self.set_network_params_op.append(self.network_params[idx].assign(param)) # Network target目标 V(s) self.td_target = tf.compat.v1.placeholder(tf.float32, [None, 1]) # Temporal Difference, will also be weights for actor_gradients时间差异,也将是actor_gradients的权重 self.td = tf.subtract(self.td_target, self.out) # Mean square error均方误差 self.loss = tflearn.mean_square(self.td_target, self.out) # Compute critic gradient计算临界梯度 self.critic_gradients = tf.gradients(self.loss, self.network_params) # Optimization Op self.optimize = tf.compat.v1.train.RMSPropOptimizer(self.lr_rate). \ apply_gradients(zip(self.critic_gradients, self.network_params))请对这段代码每句进行注释
# 定义一个类,表示 Critic 网络
class CriticNetwork(object):
def __init__(self, sess, state_dim, learning_rate):
# 初始化 Critic 网络的一些参数
self.sess = sess
self.s_dim = state_dim
self.lr_rate = learning_rate
# 创建 Critic 网络
self.inputs, self.out = self.create_critic_network()
# 获取 Critic 网络中所有的参数
self.network_params = tf.compat.v1.get_collection(tf.compat.v1.GraphKeys.TRAINABLE_VARIABLES, scope='critic')
# 定义一个占位符,表示 Critic 网络的输入参数
self.input_network_params = []
for param in self.network_params:
self.input_network_params.append(tf.compat.v1.placeholder(tf.float32, shape=param.get_shape()))
# 定义一个操作,用于设置 Critic 网络的所有参数
self.set_network_params_op = []
for idx, param in enumerate(self.input_network_params):
self.set_network_params_op.append(self.network_params[idx].assign(param))
# 定义一个占位符,表示 Critic 网络的目标输出
self.td_target = tf.compat.v1.placeholder(tf.float32, [None, 1])
# 计算 Critic 网络的 Temporal Difference
self.td = tf.subtract(self.td_target, self.out)
# 定义 Critic 网络的损失函数,使用均方误差
self.loss = tflearn.mean_square(self.td_target, self.out)
# 计算 Critic 网络的梯度
self.critic_gradients = tf.gradients(self.loss, self.network_params)
# 定义 Critic 网络的优化器
self.optimize = tf.compat.v1.train.RMSPropOptimizer(self.lr_rate).apply_gradients(zip(self.critic_gradients, self.network_params))
def calc_gradient_penalty(self, netD, real_data, fake_data): alpha = torch.rand(1, 1) alpha = alpha.expand(real_data.size()) alpha = alpha.cuda() interpolates = alpha * real_data + ((1 - alpha) * fake_data) interpolates = interpolates.cuda() interpolates = Variable(interpolates, requires_grad=True) disc_interpolates, s = netD.forward(interpolates) s = torch.autograd.Variable(torch.tensor(0.0), requires_grad=True).cuda() gradients1 = autograd.grad(outputs=disc_interpolates, inputs=interpolates, grad_outputs=torch.ones(disc_interpolates.size()).cuda(), create_graph=True, retain_graph=True, only_inputs=True, allow_unused=True)[0] gradients2 = autograd.grad(outputs=s, inputs=interpolates, grad_outputs=torch.ones(s.size()).cuda(), create_graph=True, retain_graph=True, only_inputs=True, allow_unused=True)[0] if gradients2 is None: return None gradient_penalty = (((gradients1.norm(2, dim=1) - 1) ** 2).mean() * self.LAMBDA) + \ (((gradients2.norm(2, dim=1) - 1) ** 2).mean() * self.LAMBDA) return gradient_penalty def get_loss(self, net,fakeB, realB): self.D_fake, x = net.forward(fakeB.detach()) self.D_fake = self.D_fake.mean() self.D_fake = (self.D_fake + x).mean() # Real self.D_real, x = net.forward(realB) self.D_real = (self.D_real+x).mean() # Combined loss self.loss_D = self.D_fake - self.D_real gradient_penalty = self.calc_gradient_penalty(net, realB.data, fakeB.data) return self.loss_D + gradient_penalty,return self.loss_D + gradient_penalty出现错误:TypeError: unsupported operand type(s) for +: 'Tensor' and 'NoneType'
这个错误是因为在 calc_gradient_penalty 函数中,如果 gradients2 是 None,则会返回 None。在 get_loss 函数中,如果 gradient_penalty 是 None,则返回的就是 self.loss_D + None,这导致了 TypeError 错误。
为了解决这个问题,你可以在 calc_gradient_penalty 函数中添加一个条件判断,如果 gradients2 是 None,则返回 0.0,而不是 None。这样,当计算 gradient_penalty 时,即使 gradients2 是 None,也不会导致错误。修改后的代码如下:
```
def calc_gradient_penalty(self, netD, real_data, fake_data):
alpha = torch.rand(1, 1)
alpha = alpha.expand(real_data.size())
alpha = alpha.cuda()
interpolates = alpha * real_data + ((1 - alpha) * fake_data)
interpolates = interpolates.cuda()
interpolates = Variable(interpolates, requires_grad=True)
disc_interpolates, s = netD.forward(interpolates)
s = torch.autograd.Variable(torch.tensor(0.0), requires_grad=True).cuda()
gradients1 = autograd.grad(outputs=disc_interpolates, inputs=interpolates,
grad_outputs=torch.ones(disc_interpolates.size()).cuda(),
create_graph=True, retain_graph=True, only_inputs=True, allow_unused=True)[0]
gradients2 = autograd.grad(outputs=s, inputs=interpolates,
grad_outputs=torch.ones(s.size()).cuda(),
create_graph=True, retain_graph=True,
only_inputs=True, allow_unused=True)[0]
if gradients2 is None:
return 0.0
gradient_penalty = (((gradients1.norm(2, dim=1) - 1) ** 2).mean() * self.LAMBDA) + \
(((gradients2.norm(2, dim=1) - 1) ** 2).mean() * self.LAMBDA)
return gradient_penalty
def get_loss(self, net,fakeB, realB):
self.D_fake, x = net.forward(fakeB.detach())
self.D_fake = self.D_fake.mean()
self.D_fake = (self.D_fake + x).mean()
# Real
self.D_real, x = net.forward(realB)
self.D_real = (self.D_real+x).mean()
# Combined loss
self.loss_D = self.D_fake - self.D_real
gradient_penalty = self.calc_gradient_penalty(net, realB.data, fakeB.data)
if gradient_penalty == None:
gradient_penalty = 0.0
return self.loss_D + gradient_penalty
```