Daniel Voigt Godoy - Deep Learning with PyTorch Step-by-Step A Beginner’s Guide-leanpub

Padding in Computer Vision
Padding an image simply means adding zeros around it. An image is worth a
thousand words in this case.
By adding columns and rows of zeros around it, we expand the input image
such that the gray region starts centered in the actual top-left corner of the
input image. This simple trick can be used to preserve the original size of the
image.
Padding
Now, we’ll stuff sequences with zeros so they all have matching sizes. Simple
enough, right?
"OK, it is simple, but why are we doing it?"
We need to pad the sequences because we cannot create a tensor out of a list of
elements with different sizes:
all_seqs = [s0, s1, s2]
torch.as_tensor(all_seqs)
654 | Chapter 8: Sequences