ArrayFire is a High Performance software library for parallel computing with an easy-to-use API. It has been released with a BSD 3-Clause License. You can take a look at the github page example https://github.com/arrayfire/arrayfire which gives a clear idea on how to use this library effectively in leveraging the power of your CPU/GPU with minimal effort.
At the risk of taking things entirely too seriously, I wrote this article in which I tried to convey my thoughts on preparing and giving public presentations. What was intended to be a few quick thoughts turned into a fairly long piece. So if you care about presenting, or are just bored and want something long to read, please check it out.