Using nn.ModuleList over Python list dramatically slows down training












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I'm training a very simple model that takes the number of hidden layers as a parameter. I originally stored these hidden layers in a vanilla python list , however when converting this list to a nn.ModuleList, training slows down dramatically by at least one order of magnitude!



AdderNet



class AdderNet(nn.Module):
def __init__(self, num_hidden, hidden_width):
super(AdderNet, self).__init__()
self.relu = nn.ReLU()

self.hiddenLayers =
self.inputLayer = nn.Linear(2, hidden_width)
self.outputLayer = nn.Linear(hidden_width, 1)

for i in range(num_hidden):
self.hiddenLayers.append(nn.Linear(hidden_width, hidden_width))

self.hiddenLayers = nn.ModuleList(self.hiddenLayers) # <--- causes DRAMATIC slowdown!

def forward(self, x):
out = self.inputLayer(x)
out = self.relu(out)

for layer in self.hiddenLayers:
out = layer(out)
out = self.relu(out)

return self.outputLayer(out)


Training



for epoch in range(num_epochs):
for i in range(0,len(data)):
out = model.forward(data[i].x)
loss = lossFunction(out, data[i].y)

optimizer.zero_grad()
loss.backward()
optimizer.step()









share|improve this question





























    0















    I'm training a very simple model that takes the number of hidden layers as a parameter. I originally stored these hidden layers in a vanilla python list , however when converting this list to a nn.ModuleList, training slows down dramatically by at least one order of magnitude!



    AdderNet



    class AdderNet(nn.Module):
    def __init__(self, num_hidden, hidden_width):
    super(AdderNet, self).__init__()
    self.relu = nn.ReLU()

    self.hiddenLayers =
    self.inputLayer = nn.Linear(2, hidden_width)
    self.outputLayer = nn.Linear(hidden_width, 1)

    for i in range(num_hidden):
    self.hiddenLayers.append(nn.Linear(hidden_width, hidden_width))

    self.hiddenLayers = nn.ModuleList(self.hiddenLayers) # <--- causes DRAMATIC slowdown!

    def forward(self, x):
    out = self.inputLayer(x)
    out = self.relu(out)

    for layer in self.hiddenLayers:
    out = layer(out)
    out = self.relu(out)

    return self.outputLayer(out)


    Training



    for epoch in range(num_epochs):
    for i in range(0,len(data)):
    out = model.forward(data[i].x)
    loss = lossFunction(out, data[i].y)

    optimizer.zero_grad()
    loss.backward()
    optimizer.step()









    share|improve this question



























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      I'm training a very simple model that takes the number of hidden layers as a parameter. I originally stored these hidden layers in a vanilla python list , however when converting this list to a nn.ModuleList, training slows down dramatically by at least one order of magnitude!



      AdderNet



      class AdderNet(nn.Module):
      def __init__(self, num_hidden, hidden_width):
      super(AdderNet, self).__init__()
      self.relu = nn.ReLU()

      self.hiddenLayers =
      self.inputLayer = nn.Linear(2, hidden_width)
      self.outputLayer = nn.Linear(hidden_width, 1)

      for i in range(num_hidden):
      self.hiddenLayers.append(nn.Linear(hidden_width, hidden_width))

      self.hiddenLayers = nn.ModuleList(self.hiddenLayers) # <--- causes DRAMATIC slowdown!

      def forward(self, x):
      out = self.inputLayer(x)
      out = self.relu(out)

      for layer in self.hiddenLayers:
      out = layer(out)
      out = self.relu(out)

      return self.outputLayer(out)


      Training



      for epoch in range(num_epochs):
      for i in range(0,len(data)):
      out = model.forward(data[i].x)
      loss = lossFunction(out, data[i].y)

      optimizer.zero_grad()
      loss.backward()
      optimizer.step()









      share|improve this question
















      I'm training a very simple model that takes the number of hidden layers as a parameter. I originally stored these hidden layers in a vanilla python list , however when converting this list to a nn.ModuleList, training slows down dramatically by at least one order of magnitude!



      AdderNet



      class AdderNet(nn.Module):
      def __init__(self, num_hidden, hidden_width):
      super(AdderNet, self).__init__()
      self.relu = nn.ReLU()

      self.hiddenLayers =
      self.inputLayer = nn.Linear(2, hidden_width)
      self.outputLayer = nn.Linear(hidden_width, 1)

      for i in range(num_hidden):
      self.hiddenLayers.append(nn.Linear(hidden_width, hidden_width))

      self.hiddenLayers = nn.ModuleList(self.hiddenLayers) # <--- causes DRAMATIC slowdown!

      def forward(self, x):
      out = self.inputLayer(x)
      out = self.relu(out)

      for layer in self.hiddenLayers:
      out = layer(out)
      out = self.relu(out)

      return self.outputLayer(out)


      Training



      for epoch in range(num_epochs):
      for i in range(0,len(data)):
      out = model.forward(data[i].x)
      loss = lossFunction(out, data[i].y)

      optimizer.zero_grad()
      loss.backward()
      optimizer.step()






      python neural-network pytorch






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      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 21 '18 at 5:27









      Milo Lu

      1,61511427




      1,61511427










      asked Nov 21 '18 at 0:52









      Stephen LaskyStephen Lasky

      140112




      140112
























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