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

Creating images


Image objects can be created using the following function call:

cl_mem clCreateImage (cl_context context,cl_mem_flags flags,const cl_image_format *image_format,const cl_image_desc *image_desc,void *host_ptr,cl_int *errcode_ret)

A single function call supports the creation of a 1D, 2D, and 3D image object, which can either be transferred to the device or can be formed in the device. Besides this, the same function call can be used to create an array of 1D and 2D image objects using the cl_image_desc data structure. We will discuss more on this later. In OpenCL 1.1 instead of one function clCreateImage, there were two different functions clCreateImage2D and clCreateImage3D.

The function call clCreateImage takes the usual four arguments as used in the clCreateBuffer. They are the context, flags, host_ptr, and error_code. The definition of these parameters is similar to that discussed in context with clCreateBuffer. If the flags parameter is specified as 0 then the default value...