DSPEV Example

To find all the eigenvalues of the symmetric matrix

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

together with an approximate error bound for the computed eigenvalues.

Example program
Example data
Example results