DSTEVR Example

To find the eigenvalues whose indices are in the range $\left[\vphantom{2, 3}\right.$2, 3$\left.\vphantom{2, 3}\right]$, and the corresponding eigenvectors, of the symmetric tridiagonal matrix

A = $$\left(\vphantom{ \begin{array}{rrrr} 1 & 1 & 0 & 0 \\ 1 & 4 & 2 & 0 \\ 0 & 2 & 9 & 3 \\ 0 & 0 & 3 & 16 \end{array} }\right.$$$$\begin{array}{rrrr} 1 & 1 & 0 & 0 \\ 1 & 4 & 2 & 0 \\ 0 & 2 & 9 & 3 \\ 0 & 0 & 3 & 16 \end{array}$$$$\left.\vphantom{ \begin{array}{rrrr} 1 & 1 & 0 & 0 \\ 1 & 4 & 2 & 0 \\ 0 & 2 & 9 & 3 \\ 0 & 0 & 3 & 16 \end{array} }\right)$$.

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