For some square images, I'd like to use torch.nn.Conv2d with the kernel as a vertical block. As in, the kernel size is defined as max value of the first dimension by 1. Since the first dimension has no more room, I'd like to have 0 stride along that first dimension. I tried using the following definition:

self.conv1 = torch.nn.Conv2d(3, 32, (max_dim_0, 1),
                                    stride=(0, 1),

However, this causes my training loop throws a RuntimeError: non-positive stride is not supported exception. Is there a way to define the kernel as a vertical block?

  • $\begingroup$ does this help? $\endgroup$
    – Nikos M.
    Commented Jul 26, 2020 at 8:11

1 Answer 1


Setting stride to 0 is not necessary, torch will simply compute with respect to the input tensor sizes, so you can set stride to (1,1).

For x of size (batch_size, 3, max_dim_0, max_dim_0) (square image) the tensor output will be of size (batch_size, 32, 1, max_dim_0).

  • $\begingroup$ Thanks this worked for me :) $\endgroup$ Commented Jul 28, 2020 at 11:05

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