Confused about nb_stacks

[johnchenresearch]

I'm reading the code and I'm just a little confused about the below lines:
for s in range(nb_stacks):
for i in dilatations:
x, skip_out = residual_block(x, s, i, activation, nb_filters, kernel_size)

What is the interpretation of this? In the paper, I had thought that each layer would have its own dilation rate, typically 2 ** i for the ith layer. What is happening here?

[alextheseal]

I'm a bit confused about it too, but my understanding is that you can stack up the TCN blocks, increasing the receptive field as you do. So for a single stack, if the kernel size was 2, the dilations were [1,2,4,8], you would get the situation in the image below:

so a receptive field of 16.

If you specified 2 stacks my intuition is that you would get the situation below, that is, an increase in the receptive field to 32:

If you increased the number of stacks to 3, the size of the receptive field would increase again, such as below:

Philippe, can you please confirm whether my understanding is correct please.

[philipperemy]

@alextheseal I wrote that some times ago but it looks correct.

[alextheseal]

Thanks!

[philipperemy]

Yeah I updated the code to reflect this. It was a bit confusing sorry about that :)

[philipperemy]

I'll update it again to incorporate only one single parameter for the dilations: N

dilations = [2**i for i in range(N)]

So that when we specify N=4, it would mean [0, 1, 2, 4, 8]