This example computes the two smallest eigenvalues, and the associated eigenvectors, of the matrix
, where
using packed storage. Here
is Hermitian and must first be reduced to tridiagonal form
by
zhptrd. The program then calls
dstebz to compute the requested eigenvalues and
zstein to compute the associated eigenvectors of
. Finally
zupmtr is called to transform the eigenvectors to those of
.