title: Arbitrary filters for conv2d (as opposed to rectangular)
body: <p>I using convolutional layers on data samples that consist of 2d images. One option for the shape of the filter is 1x2, which acts on a 1x2 contiguous block of two neighbor pixels. What if I want to have a filter which also acts on 2 pixels, but the pixels are separated by another one between them? Is it possible to encode such a filter for convolutions in the neural network?</p>