##### ptcon

###### Prototype

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

    ptcon( const VectorD& d, const VectorE& e, const Scalar >, Scalar > );

###### Description

`ptcon` (short for $FRIENDLY_NAME) provides a C++ interface to LAPACK routines SPTCON, DPTCON, CPTCON, and ZPTCON. `ptcon` computes the reciprocal of the condition number (in the 1-norm) of a complex Hermitian positive definite tridiagonal matrix using the factorization A = LD*LH or A = U*H*D*U computed by ZPTTRF.

Norm(inv(A)) is computed by a direct method, and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).

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

Table 1.282. Dispatching of ptcon

Value type of VectorD | LAPACK routine
--- | ---
`float` | SPTCON
`double` | DPTCON
`complex<float>` | CPTCON
`complex<double>` | ZPTCON

###### Definition

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

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

this will output

    [5] 0 1 2 3 4 5

###### Notes

###### See Also

- Originating Fortran source files sptcon.f, dptcon.f, cptcon.f, and zptcon.f at Netlib.