about this book Open CL is a complex subject. To code even the simplest of applications, a developer needs to understand host programming, device programming, and the mechanisms that transfer data between the host and device. The goal of this book is to show how these tasks are accomplished and how to put them to use in practical applications. The format of this book is tutorial-based. That is, each new concept is followed by example code that demonstrates how the theory is used in an application. Many of the early applications are trivially basic, and some do nothing more than obtain informa- tion about devices and data structures. But as the book progresses, the code becomes more involved and makes fuller use of both the host and the target device. In the later chapters, the focus shifts from learning how Open CL works to putting Open CL to use in processing vast amounts of data at high speed. Audience In writing this book, I've assumed that readers have never heard of Open CL and know nothing about distributed computing or high-performance computing. I've done my best to present concepts like task-parallelism and SIMD (single instruction, multiple data) development as simply and as straightforwardly as possible. But because the Open CL API is based on C, this book presumes that the reader has a solid understanding of C fundamentals. Readers should be intimately familiar with pointers, arrays, and memory access functions like malloc and free . It also helps to be cognizant of the C functions declared in the common math library, as most of the ker- nel functions have similar names and usages. xix