DSPEVX Example

To find the eigenvalues in the half-open interval $\left(\vphantom{-1, 1}\right.$ -1, 1$\left.\vphantom{-1, 1}\right]$, and the corresponding eigenvectors, of the symmetric matrix

A = $$\left(\vphantom{ \begin{array}{rrrr} 1 & 2 & 3 & 4 \\ 2 & 2 & 3 & 4 \\ 3 & 3 & 3 & 4 \\ 4 & 4 & 4 & 4 \end{array} }\right.$$$$\begin{array}{rrrr} 1 & 2 & 3 & 4 \\ 2 & 2 & 3 & 4 \\ 3 & 3 & 3 & 4 \\ 4 & 4 & 4 & 4 \end{array}$$$$\left.\vphantom{ \begin{array}{rrrr} 1 & 2 & 3 & 4 \\ 2 & 2 & 3 & 4 \\ 3 & 3 & 3 & 4 \\ 4 & 4 & 4 & 4 \end{array} }\right)$$.

Example program
Example data
Example results