Zhiqiang Cai, Jan Mandel, Steve McCormick, Multigrid Methods for Nearly Singular Linear Equations and Eigenvalue Problems, SIAM Journal on Numerical Analysis, Vol. 34, No. 1 (Feb., 1997), pp. 178-200 ...

In this paper the authors develop a general framework for calculating the eigenvalues of a symmetric matrix using ordinary differential equations. New algorithms are suggested and old algorithms, ...