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97. CEIG: Eigenvalues and Eigenvectors for (H-lS) C=0
by H. H. Michels, C. P. VanDine and P. Elliott, United Aircraft Research Laboratories Subroutine computes the eigenvalues and eigenvectors of a real symmetric matrix H with the metric S, also real and symmetric. The method employs only a single matrix diagonalization instead of the usual two. The use of either of two rapid eigenvalue routines, NESBET (QCPE 93) for a single root or GIVENS (QCPE 62) for more than one root, makes this method quite fast. It is thus well suited for large matrices. Requires QCPE 62 or QCPE 93 FORTRAN IV (IBM 7090, CDC 3600, Univac 1108) Lines of Code: 199 Recommended Citation: H. H. Michels et al., QCPE 11, 97 (1966). |