##### symv

###### Prototype

There is one prototype of `symv` available, please see below.

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

###### Description

`symv` (short for symmetric matrix-vector operation) provides a C++ interface to BLAS routines SSYMV and DSYMV. `symv` performs the matrix-vector operation

y := alpha*A*x + beta*y,

where alpha and beta are scalars, x and y are n element vectors and A is an n by n symmetric matrix.

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 1.64. Dispatching of symv.

Value type of MatrixA | BLAS routine | CBLAS routine | CUBLAS routine
--- | --- | --- | ---
`float` | SSYMV | cblas_ssymv | cublasSsymv
`double` | DSYMV | cblas_dsymv | Unavailable

The original routines SSYMV and DSYMV have ten arguments, whereas `symv` requires five arguments.

Table 1.65. Deduction of arguments of symv.

###### Definition

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

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

this will output

    [5] 0 1 2 3 4 5

###### Notes

###### See Also

- Originating Fortran source files ssymv.f and dsymv.f at Netlib.