https://rockt.github.io/2018/04/30/einsum
Einsum is All you Need – Einstein Summation in Deep Learning
Tim Rocktäschel
30/04/2018 – updated 02/05/2018
“If you are anything like me, you find it difficult to remember the names and signatures of all the different functions in PyTorch/TensorFlow for calculating dot products, outer products… Einsum notation is an elegant way to express all of these…”