A Note on Computing Eigenvalues of Banded Hermitian Toeplitz Matrices
William F. Trench · SIAM Journal on Scientific Computing · 1993
It is pointed out that the author’s $O(n^2 )$ algorithm for computing individual eigenvalues of an arbitrary $n \times n$ Hermitian Toeplitz matrix $T_n $ reduces to an $O(rn)$ algorithm if $T_n $ is banded, with bandwidth r.