f08gtf generates the complex unitary matrix
, which was determined by
f08gsf when reducing a Hermitian matrix to tridiagonal form.
f08gtf is intended to be used after a call to
f08gsf, which reduces a complex Hermitian matrix
to real symmetric tridiagonal form
by a unitary similarity transformation:
.
f08gsf represents the unitary matrix
as a product of
elementary reflectors.
The computed matrix
differs from an exactly unitary matrix by a matrix
such that
where
is the
machine precision.
Background information to multithreading can be found in the
Multithreading documentation.
Please consult the
X06 Chapter Introduction for information on how to control and interrogate the OpenMP environment used within this routine. Please also consult the
Users' Note for your implementation for any additional implementation-specific information.
The real analogue of this routine is
f08gff.
This example computes all the eigenvalues and eigenvectors of the matrix
, where
using packed storage. Here
is Hermitian and must first be reduced to tridiagonal form by
f08gsf. The program then calls
f08gtf to form
, and passes this matrix to
f08jsf which computes the eigenvalues and eigenvectors of
.