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<p>我根据本文编写了一个模块:<a href="http://www.wildml.com/2015/12/implementing-a-cnn-for-text-classification-in-tensorflow/" rel="nofollow noreferrer">http://www.wildml.com/2015/12/implementing-a-cnn-for-text-classification-in-tensorflow/</a></p>
<p>其思想是将输入传递到多个流中,然后合并到一起并连接到FC层。我将源代码分成3个自定义模块:<code>TextClassifyCnnNet</code>>;<code>FlatCnnLayer</code>>;<code>FilterLayer</code></p>
<p>过滤层:</p>
<pre><code>class FilterLayer(nn.Module):
def __init__(self, filter_size, embedding_size, sequence_length, out_channels=128):
super(FilterLayer, self).__init__()
self.model = nn.Sequential(
nn.Conv2d(1, out_channels, (filter_size, embedding_size)),
nn.ReLU(inplace=True),
nn.MaxPool2d((sequence_length - filter_size + 1, 1), stride=1)
)
for m in self.modules():
if isinstance(m, nn.Conv2d):
n = m.kernel_size[0] * m.kernel_size[1] * m.out_channels
m.weight.data.normal_(0, math.sqrt(2. / n))
def forward(self, x):
return self.model(x)
</code></pre>
<p>扁平图层:</p>
^{pr2}$
<p>textClassifyCnnet(主模块):</p>
<pre><code>class TextClassifyCnnNet(nn.Module):
def __init__(self, embedding_size, sequence_length, num_classes, filter_sizes=[3, 4, 5], out_channels=128):
super(TextClassifyCnnNet, self).__init__()
self.flat_layer = FlatCnnLayer(embedding_size, sequence_length, filter_sizes=filter_sizes,
out_channels=out_channels)
self.model = nn.Sequential(
self.flat_layer,
nn.Linear(out_channels * len(filter_sizes), num_classes)
)
def forward(self, x):
x = self.model(x)
return x
def fit(net, data, save_path):
if torch.cuda.is_available():
net = net.cuda()
for param in list(net.parameters()):
print(type(param.data), param.size())
optimizer = optim.Adam(net.parameters(), lr=0.01, weight_decay=0.1)
X_train, X_test = data['X_train'], data['X_test']
Y_train, Y_test = data['Y_train'], data['Y_test']
X_valid, Y_valid = data['X_valid'], data['Y_valid']
n_batch = len(X_train) // batch_size
for epoch in range(1, n_epochs + 1): # loop over the <a href="https://www.cnpython.com/pypi/dataset" class="inner-link">dataset</a> multiple times
net.train()
start = 0
end = batch_size
for batch_idx in range(1, n_batch + 1):
# get the inputs
x, y = X_train[start:end], Y_train[start:end]
start = end
end = start + batch_size
# zero the parameter gradients
optimizer.zero_grad()
# forward + backward + optimize
predicts = _get_predict(net, x)
loss = _get_loss(predicts, y)
loss.backward()
optimizer.step()
if batch_idx % display_step == 0:
print('Train Epoch: {} [{}/{} ({:.0f}%)]\tLoss: {:.6f}'.format(
epoch, batch_idx * len(x), len(X_train), 100. * batch_idx / (n_batch + 1), loss.data[0]))
# print statistics
if epoch % display_step == 0 or epoch == 1:
net.eval()
valid_predicts = _get_predict(net, X_valid)
valid_loss = _get_loss(valid_predicts, Y_valid)
valid_accuracy = _get_accuracy(valid_predicts, Y_valid)
print('\r[%d] loss: %.3f - accuracy: %.2f' % (epoch, valid_loss.data[0], valid_accuracy * 100))
print('\rFinished Training\n')
net.eval()
test_predicts = _get_predict(net, X_test)
test_loss = _get_loss(test_predicts, Y_test).data[0]
test_accuracy = _get_accuracy(test_predicts, Y_test)
print('Test loss: %.3f - Test accuracy: %.2f' % (test_loss, test_accuracy * 100))
torch.save(net.flat_layer.state_dict(), save_path)
def _get_accuracy(predicts, labels):
predicts = torch.max(predicts, 1)[1].data[0]
return np.mean(predicts == labels)
def _get_predict(net, x):
# wrap them in Variable
inputs = torch.from_numpy(x).float()
# convert to cuda tensors if cuda flag is true
if torch.cuda.is_available:
inputs = inputs.cuda()
inputs = Variable(inputs)
return net(inputs)
def _get_loss(predicts, labels):
labels = torch.from_numpy(labels).long()
# convert to cuda tensors if cuda flag is true
if torch.cuda.is_available:
labels = labels.cuda()
labels = Variable(labels)
return F.cross_entropy(predicts, labels)
</code></pre>
<p>似乎每个历元的参数都会稍微更新一点,整个过程的精度都保持不变。虽然在Tensorflow中使用相同的实现和相同的参数,但它可以正确运行。在</p>
<p>我是新来的Pythorch,所以可能我的指示有问题,请帮我找出原因。谢谢您!在</p>
<p>注:我尝试使用<code>F.nll_loss</code>+<code>F.log_softmax</code>而不是<code>F.cross_entropy</code>。理论上,它应该返回相同的结果,但实际上打印出另一个结果(但它仍然是错误的损失值)</p>