Asked about Convolution arithmetic and a CNN in PyTorch

What is the output shape of a 3x3 convolution with stride 2 and padding 1 on a 64x64x32 input with 64 filters, and how many parameters does it have?

An answer that works

Spatially floor((64 - 3 + 2) / 2) + 1 = 32, so 32x32x64. Parameters: 3 x 3 x 32 x 64 = 18,432 weights plus 64 biases, 18,496.

Then they push further

Why do residual connections help very deep networks train?

Each block learns a correction added to its input, so an unhelpful block can stay close to the identity, and gradients flow directly through the additions to early layers without shrinking at every layer.

What gets marked up

Marked up for getting the arithmetic right out loud. Interviews for vision roles often include exactly this.

Reading an answer is not being able to give one. The section that teaches this is Convolution arithmetic and a CNN in PyTorch, 5 hours of Convolutional networks.

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