EISPACK - A PACKAGE FOR SOLVING MATRIX EIGENVALUE PROBLEMS.

EISPACK is a collection of Fortran subroutines that compute the eigenvalues and eigenvectors of matrices and matrix systems. The package can determine the eigensystem of complex general, complex Hermitian, real general, real symmetric, real symmetric band, real symmetric tridiagonal, and special real tridiagonal matrices, and generalized real and generalized real symmetric matrix systems. The subroutines are based mainly on Algol procedures published in the Handbook series of Springer-Verlaga by Wilkinson and Reinsch (1971) and the QZ algorithm of Moler and Stewart (1973). The algorithms have been adapted to Fortran and thoroughly tested on a wide range of different computers. The software has been certified and is supported by the developers.