Two working algorithms for the eigenvalues of a symmetric tridiagonal matrix
W. Kahan, J. M. Varah · 1966
Two tested programs are supplied to find the eigenvalues of a symmetric tridiagonal matrix. One program uses a square-root-free version of the QR algorithm. The other uses a compact kind of Sturm sequence algorithm. These programs are faster and more accurate than the other comparable programs published previously with which they have been compared.