THIS INFORMATION IS OBSOLETE AND IS PROVIDED ONLY FOR ITS HISTORICAL VALUE

by Isaiah Shavitt, Battelle Memorial Institute, Columbus, Ohio 43201

The subroutine EIGEN computes an eigenvalue (usually the lowest) and corresponding eigenvector of a real symmetric matrix. The matrix need not fit into the central memory, and only the non-zero elements (ordered by row for the lower triangle and suitably identified) need to be provided. The user must supply a subroutine ROW to access the matrix, one row at a time. The method is iterative, and an initial guess for the desired eigenvector must be provided.

FORTRAN IV Lines of Code: 387 Recommended Citation: I. Shavitt, QCPE 11, 172 (1970).