OpenCL’s data structures and functions are unique. Even the most introductory application is difficult for a newcomer to grasp. You really can’t dip your foot in the pool—you either know OpenCL or you don’t. In this article based on OpenCL in Action, author Matthew Scarpino explains how host applications work and then shows how kernels execute on a device. Then, he walks us through an example application with a kernel that adds 64 floating-point values together.

A Gentle Introduction to OpenCL (PDF)