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

Memory objects


Memory objects are encapsulated by cl_mem data structure. The two important functions to create a memory object are as follows:

cl_mem clCreateBuffer (cl_context context,cl_mem_flags flags,size_t size,void *host_ptr,cl_int *errcode_ret)
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)

Note that both the buffer and image data objects are of type cl_mem and these objects form the most important basic component in OpenCL. Both these functions return the cl_mem objects and the type of memory is specified by the flags variable of type cl_mem_flags. For comparison purpose the clCreateImage function is shown here. More details of this will be discussed in the next chapter. The possible values for the cl_mem_flags flags are shown in the following table:

cl_mem_flags

Description

CL_MEM_READ_WRITE

The buffer is created in the device global memory and can be read and written...