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