##### upgtr

###### Prototype

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

    upgtr( const char uplo, const VectorAP& ap, const VectorTAU& tau,
            MatrixQ& q );

###### Description

`upgtr` (short for $FRIENDLY_NAME) provides a C++ interface to LAPACK routines SOPGTR, DOPGTR, CUPGTR, and ZUPGTR. `upgtr` generates a complex unitary matrix Q which is defined as the product of n-1 elementary reflectors H(i) of order n, as returned by ZHPTRD using packed storage:

if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),

if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).

The selection of the LAPACK routine is done during compile-time, and is determined by the type of values contained in type `VectorAP`. The type of values is obtained through the `value_type` meta-function `typename value_type<VectorAP>::type`. The dispatching table below illustrates to which specific routine the code path will be generated.

Table 1.328. Dispatching of upgtr

Value type of VectorAP | LAPACK routine
--- | ---
`float` | SOPGTR
`double` | DOPGTR
`complex<float>` | CUPGTR
`complex<double>` | ZUPGTR

###### Definition

Defined in header `boost/numeric/bindings/lapack/computational/upgtr.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/lapack/computational/upgtr.hpp>
    using namespace boost::numeric::bindings;

    lapack::upgtr( x, y, z );

this will output

    [5] 0 1 2 3 4 5

###### Notes

###### See Also

- Originating Fortran source files sopgtr.f, dopgtr.f, cupgtr.f, and zupgtr.f at Netlib.