There are two prototypes of gemv
            available, please see below. 
gemv( const Scalar >, const MatrixA& a, const VectorX& x, const Scalar >, VectorY& y );
gemv( const Scalar alpha, const MatrixA& a, const VectorX& x, const Scalar beta, VectorY& y );
            gemv (short for generic
            matrix-vector operation) provides a C++ interface to BLAS routines SGEMV,
            DGEMV, CGEMV, and ZGEMV. gemv
            performs one of the matrix-vector operations
          
y := alpha*A*x + beta*y, or y := alpha*A'*x + beta*y, or
y := alpha*conjg( A' )*x + beta*y,
where alpha and beta are scalars, x and y are vectors and A is an m by n 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 1.34. Dispatching of gemv.
| Value type of MatrixA | BLAS routine | CBLAS routine | CUBLAS routine | 
|---|---|---|---|
| 
                       | SGEMV | cblas_sgemv | cublasSgemv | 
| 
                       | DGEMV | cblas_dgemv | cublasDgemv | 
| 
                       | CGEMV | cblas_cgemv | cublasCgemv | 
| 
                       | ZGEMV | cblas_zgemv | cublasZgemv | 
            The original routines SGEMV, DGEMV, CGEMV, and ZGEMV have eleven arguments,
            whereas gemv requires
            five arguments.
          
            Defined in header boost/numeric/bindings/blas/level2/gemv.hpp.
          
Parameters
The definition of term 1
The definition of term 2
The definition of term 3.
Definitions may contain paragraphs.
#include <boost/numeric/bindings/blas/level2/gemv.hpp> using namespace boost::numeric::bindings; blas::gemv( x, y, z );
this will output
[5] 0 1 2 3 4 5