I am a beginner in pytorch, many examples on the internet for LeNet5 implementations via PyTorch. Most of them are like this:

   self.c1 = nn.Conv2d(3, 6, 5)
   self.s2 = nn.MaxPool2d(2)
   self.c3 = nn.Conv2d(6, 16, 5)
   self.s4 = nn.MaxPool2d(2)
   self.c5   = nn.Linear(16*5*5, 120)
   self.f6   = nn.Linear(120, 84)
   self.output   = nn.Linear(84, 10)


Obviously, it is not the original design by Lecun. This is just connect all feature maps in s2 with all feature maps in c3.
But in Lecun’s paper, the connection relationship between s2 and c3 c is very specified as follow:
6 feature maps connect 3 feature maps in S2, another  6 feature map connect to 4 feature maps in S2, and 3 feature maps  connect to another 4 feature maps in S2, the final 1 feature map connects all feature maps in S2.
As we know, pytorch is very flexiable, how to implement this in pytorch?