Book Image

OpenCL Programming by Example

Book Image

OpenCL Programming by Example

Overview of this book

Research in parallel programming has been a mainstream topic for a decade, and will continue to be so for many decades to come. Many parallel programming standards and frameworks exist, but only take into account one type of hardware architecture. Today computing platforms come with many heterogeneous devices. OpenCL provides royalty free standard to program heterogeneous hardware. This guide offers you a compact coverage of all the major topics of OpenCL programming. It explains optimization techniques and strategies in-depth, using illustrative examples and also provides case studies from diverse fields. Beginners and advanced application developers will find this book very useful. Beginning with the discussion of the OpenCL models, this book explores their architectural view, programming interfaces and primitives. It slowly demystifies the process of identifying the data and task parallelism in diverse algorithms. It presents examples from different domains to show how the problems within different domains can be solved more efficiently using OpenCL. You will learn about parallel sorting, histogram generation, JPEG compression, linear and parabolic regression and k-nearest neighborhood, a clustering algorithm in pattern recognition. Following on from this, optimization strategies are explained with matrix multiplication examples. You will also learn how to do an interoperation of OpenGL and OpenCL. "OpenCL Programming by Example" explains OpenCL in the simplest possible language, which beginners will find it easy to understand. Developers and programmers from different domains who want to achieve acceleration for their applications will find this book very useful.
Table of Contents (18 chapters)
OpenCL Programming by Example
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Conversions and type casts


All programming languages support converting a numerical data type to another numerical data type. There is also a need to reinterpret a data type in some other form, for example, if one wants to extract only the exponent component from a floating point data type, how can one do that? We will discuss the implicit and explicit type conversions, followed by reinterpreting the data types.

Implicit conversion

Implicit conversion refers to the conversion of a data in one type to another type, which is equivalent to the original data type. This conversion is allowed for basic data types, which is described in the table earlier. For example, the integer value 1 will be converted to an equivalent floating point value 1.0f. The corresponding hex representation is 0x3F800000. When you convert a float value to an int, the compiler will usually throw a warning. To avoid that you explicitly cast the scalar data types. Example:

float f = 2.0f;
int i = (int) f;

Explicit cast of vector...