syrk

Prototype

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

syrk( const Scalar >, const MatrixA& a, const Scalar >, MatrixC& c );

syrk( const Scalar alpha, const MatrixA& a, const Scalar beta,
        MatrixC& c );

Description

syrk (short for symmetric rank-k update) provides a C++ interface to BLAS routines SSYRK, DSYRK, CSYRK, and ZSYRK. syrk performs one of the symmetric rank k operations

C := alpha*A*A' + beta*C,

C := alpha*A'*A + beta*C,

where alpha and beta are scalars, C is an n by n symmetric matrix and A is an n by k matrix in the first case and a k by n matrix in the second case.

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

Table 1.94. Dispatching of syrk.

Value type of MatrixA	BLAS routine	CBLAS routine	CUBLAS routine
`float`	SSYRK	cblas_ssyrk	cublasSsyrk
`double`	DSYRK	cblas_dsyrk	cublasDsyrk
`complex<float>`	CSYRK	cblas_csyrk	cublasCsyrk
`complex<double>`	ZSYRK	cblas_zsyrk	cublasZsyrk

The original routines SSYRK, DSYRK, CSYRK, and ZSYRK have ten arguments, whereas syrk requires four arguments.

Table 1.95. Deduction of arguments of syrk.

Definition

Defined in header boost/numeric/bindings/blas/level3/syrk.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/level3/syrk.hpp>
using namespace boost::numeric::bindings;

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

this will output

[5] 0 1 2 3 4 5