How to solve “NotImplementedError”

I defined a three layer convolution layer(self.convs) ,the input tensor has the shape([100,10,24])

x_convs = self.convs(Variable(torch.from_numpy(X).type(torch.FloatTensor)))

>>Variable(torch.from_numpy(X).type(torch.FloatTensor)).shape

torch.Size([100, 10, 24])

>>self.convs

ModuleList(
  (0): ConvBlock(
    (conv): Conv1d(24, 8, kernel_size=(5,), stride=(1,), padding=(2,))
    (relu): ReLU()
    (maxpool): AdaptiveMaxPool1d(output_size=10)
    (zp): ConstantPad1d(padding=(1, 0), value=0)
  )
  (1): ConvBlock(
    (conv): Conv1d(8, 8, kernel_size=(5,), stride=(1,), padding=(2,))
    (relu): ReLU()
    (maxpool): AdaptiveMaxPool1d(output_size=10)
    (zp): ConstantPad1d(padding=(1, 0), value=0)
  )
  (2): ConvBlock(
    (conv): Conv1d(8, 8, kernel_size=(5,), stride=(1,), padding=(2,))
    (relu): ReLU()
    (maxpool): AdaptiveMaxPool1d(output_size=10)
    (zp): ConstantPad1d(padding=(1, 0), value=0)
  )
)

When I excuate x_convs = self.convs(Variable(torch.from_numpy(X).type(torch.FloatTensor))), it gives me the error

    `94             registered hooks while the latter silently ignores them.

     95         """

---> 96         raise NotImplementedError`

The ConvBlock is defined as below

class ConvBlock(nn.Module):
    def __init__(self, T, in_channels, out_channels, filter_size):
        super(ConvBlock, self).__init__()
        padding = self._calc_padding(T, filter_size)
        self.conv=nn.Conv1d(in_channels, out_channels, filter_size, padding=padding)
        self.relu=nn.ReLU()
        self.maxpool=nn.AdaptiveMaxPool1d(T)       
        self.zp=nn.ConstantPad1d((1, 0), 0)        
        
    def _calc_padding(self, Lin, kernel_size, stride=1, dilation=1):
        p = int(((Lin-1)*stride + 1 + dilation*(kernel_size - 1) - Lin)/2)    
        return p                                                              
    
    def forward(self, x):
        x = x.permute(0,2,1)    
        x = self.conv(x)        
        x = self.relu(x)
        x = self.maxpool(x)     
        x = x.permute(0,2,1)    
        return x

The “forward” function has correct indent, so I cannot figure it out what is going on.

Answer

You are trying to call a ModuleList, which is a list (i.e. a list object in Python), slightly modified for being used with PyTorch.

A quick fix would be to call the self.convs as:

x_convs = self.convs[0](Variable(torch.from_numpy(X).type(torch.FloatTensor)))

if len(self.convs) > 1:
    for conv in self.convs[1:]:
        x_convs = conv(x_convs)

That is, although self.convs is a list, each member of it is a Module. You can directly call each member of the self.convs, using its index, e.g. “self.convsan_index`.

Or, you can do it with the help of functools module:

from functools import reduce

def apply_layer(layer_input, layer): 
    return layer(layer_input)

output_of_self_convs = reduce(apply_layer, self.convs, Variable(torch.from_numpy(X).type(torch.FloatTensor)))

P.S. Though, the Variable keyword is not used anymore.