her2

Prototype

There are two prototypes of her2 available, please see below.

her2( const Scalar >, const VectorX& x, const VectorY& y, MatrixA& a );

her2( const Scalar alpha, const VectorX& x, const VectorY& y,
        MatrixA& a );

Description

her2 (short for hermitian rank-2 update) provides a C++ interface to BLAS routines SSYR2, DSYR2, CHER2, and ZHER2. her2 performs the hermitian rank 2 operation

A := alpha*x*conjg( y' ) + conjg( alpha )*y*conjg( x' ) + A,

where alpha is a scalar, x and y are n element vectors and A is an n by n hermitian matrix.

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 1.46. Dispatching of her2.

Value type of VectorX	BLAS routine	CBLAS routine	CUBLAS routine
`float`	SSYR2	cblas_ssyr2	cublasSsyr2
`double`	DSYR2	cblas_dsyr2	Unavailable
`complex<float>`	CHER2	cblas_cher2	cublasCher2
`complex<double>`	ZHER2	cblas_zher2	Unavailable

The original routines SSYR2, DSYR2, CHER2, and ZHER2 have nine arguments, whereas her2 requires four arguments.

Table 1.47. Deduction of arguments of her2.

Definition

Defined in header boost/numeric/bindings/blas/level2/her2.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/level2/her2.hpp>
using namespace boost::numeric::bindings;

blas::her2( x, y, z );

this will output

[5] 0 1 2 3 4 5