The EANet model leverages external attention. The computational complexity of traditional self attention is O(d * N ** 2), where d is the embedding size, and N is the number of patch. the authors find that most pixels are closely related to just a few other pixels, and an N-to-N attention matrix may be redundant. So, they propose as an alternative an external attention module where the computational complexity of external attention is O(d * S * N). As d and S are hyper-parameters, the proposed algorithm is linear in the number of pixels. In fact, this is equivalent to a drop patch operation, because a lot of information contained in a patch in an image is redundant and unimportant.