axpy

Prototype

There are two prototypes of axpy available, please see below.

axpy( const Scalar >, const VectorX& x, VectorY& y );

axpy( const Scalar a, const VectorX& x, VectorY& y );

Description

axpy (short for a times x plus y) provides a C++ interface to BLAS routines SAXPY, DAXPY, CAXPY, and ZAXPY.

The selection of the BLAS routine is done during compile-time, and is determined by the type of values contained in type VectorX. The type of values is obtained through the value_type meta-function typename value_type<VectorX>::type. Table X below illustrates to which specific routine this dispatching will take place.

Table 1.6. Dispatching of axpy.

Value type of VectorX	BLAS routine	CBLAS routine	CUBLAS routine
`float`	SAXPY	cblas_saxpy	cublasSaxpy
`double`	DAXPY	cblas_daxpy	cublasDaxpy
`complex<float>`	CAXPY	cblas_caxpy	cublasCaxpy
`complex<double>`	ZAXPY	cblas_zaxpy	Unavailable

The original routines SAXPY, DAXPY, CAXPY, and ZAXPY have six arguments, whereas axpy requires three arguments.

Table 1.7. Deduction of arguments of axpy.

Definition

Defined in header boost/numeric/bindings/blas/level1/axpy.hpp.

Parameters or Requirements on Types

Parameters

MatrixA

The definition of term 1

MatrixB

The definition of term 2

MatrixC

The definition of term 3.

Definitions may contain paragraphs.

Complexity

Example

#include <boost/numeric/bindings/blas/level1/axpy.hpp>
using namespace boost::numeric::bindings;

blas::axpy( x, y, z );

this will output

[5] 0 1 2 3 4 5