Using Intel's valarray Implementation

Intel's valarray implementation allows you to declare huge arrays for parallel processing. Improved implementation of valarray is tied up with calling the IPP libraries that are part of Intel® Integrated Performance Primitives (Intel® IPP). Intel® IPP is part of the product.

Using valarray in Source Code

To use valarrays in your source code, include the valarray header file , <valarray>. The <valarray> header file is located in the path <installdir>/perf_header.

The example code below shows a valarray addition operation (+) specialized through use of Intel's implementation of valarray:

#include <valarray>

void test( )

  std::valarray<float> vi(N), va(N);

…

  vi = vi + va;  //array addition

…

Note

To use the static merged library containing all CPU-specific optimized versions of the library code, you need to call the ippStaticInit function first, before any IPP calls. This ensures automatic dispatch to the appropriate version of the library code for Intel® processor and the generic version of the library code for non-Intel processor at runtime. If you do not call ippStaticInit first, the emerged library will use the generic instance of the code. If you are using the dynamic version of the libraries, you do not need to call ippStaticInit.

Compiling valarray Source Code

To compile your valarray source code, the compiler option, /Quse-intel-optimized-headers (for Windows* OS) or -use-intel-optimized-headers (for Linux* and MacOS* X OSes), is used to include the required valarray header file and all the necessary IPP library files.

The following examples illustrate two instances of how to compile and link a program to include the Intel valarray replacement header file and link with the Intel® Integrated Performance Primitives (Intel® IPP) libraries. Refer to the Intel® IPP documentation for details.

In the following examples, "merged" libraries means using a static library that contains all the CPU-specific variants of the library code.

Windows* OS examples:

The following command line performs a one-step compilation for a system based on IA-32 architecture, running Windows OS:

icl /Quse-intel-optimized-headers source.cpp

The following command lines perform separate compile and link steps for a system based on IA-32 architecture, running Windows OS:

DLL (dynamic):

icl /Quse-intel-optimized-headers /c source.cpp

icl source.obj /Quse-intel-optimized-headers

Merged (static):

icl /Quse-intel-optimized-headers /c source.cpp
icl source.obj /Quse-intel-optimized-headers

Linux* OS examples:

The following command line performs a one-step compilation for a system based on Intel® 64 architecture, running Linux OS:

icpc -use-intel-optimized-headers source.cpp

The following command lines perform separate compile and link steps for a system based on Intel® 64 architecture, running Linux OS:

so (dynamic):

icpc -use-intel-optimized-headers -c source.cpp

icpc source.o -use-intel-optimized-headers

Merged (static):

icpc -use-intel-optimized-headers -c source.cpp

icpc source.o -use-intel-optimized-headers

Optimization Notice
The Intel® Integrated Performance Primitives (Intel® IPP) library contains functions that are more highly optimized for Intel microprocessors than for other microprocessors. While the functions in the Intel® IPP library offer optimizations for both Intel and Intel-compatible microprocessors, depending on your code and other factors, you will likely get extra performance on Intel microprocessors. While the paragraph above describes the basic optimization approach for the Intel® IPP library as a whole, the library may or may not be optimized to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include Intel® Streaming SIMD Extensions 2 (Intel® SSE2), Intel® Streaming SIMD Extensions 3 (Intel® SSE3), and Supplemental Streaming SIMD Extensions 3 (Intel® SSSE3) instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Intel recommends that you evaluate other library products to determine which best meets your requirements.

Optimization Notice

The Intel® Integrated Performance Primitives (Intel® IPP) library contains functions that are more highly optimized for Intel microprocessors than for other microprocessors. While the functions in the Intel® IPP library offer optimizations for both Intel and Intel-compatible microprocessors, depending on your code and other factors, you will likely get extra performance on Intel microprocessors.

While the paragraph above describes the basic optimization approach for the Intel® IPP library as a whole, the library may or may not be optimized to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include Intel® Streaming SIMD Extensions 2 (Intel® SSE2), Intel® Streaming SIMD Extensions 3 (Intel® SSE3), and Supplemental Streaming SIMD Extensions 3 (Intel® SSSE3) instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors.

Intel recommends that you evaluate other library products to determine which best meets your requirements.