f77 [ flags ] file(s) ... -L/usr/local/lib -lgjlC (K&R, 89, 99), C++ (98):SUBROUTINE tql1(n,d,e,ierr) DOUBLE PRECISION d(*), e(*) INTEGER ierr, n
cc [ flags ] -I/usr/local/include file(s) ... -L/usr/local/lib -lgjl
Use#include <gjl.h>to get this prototype:void tql1(const fortran_integer * n_, fortran_double_precision d_[], fortran_double_precision e_[], fortran_integer * ierr_);
NB: The definition of C/C++ data types fortran_ xxx, and the mapping of Fortran external names to C/C++ external names, is handled by the C/C++ header file. That way, the same function or subroutine name can be used in C, C++, and Fortran code, independent of compiler conventions for mangling of external names in these programming languages.
Last code modification: 31-Aug-1983
On return, the original contents of d(*) and e(*) will have been destroyed, and d(*) will contain the eigenvalues in ascending order.
The error indicator, ierr, is normally set to zero on return. However, if an error exit is made, ierr is set to a positive value, and then the eigenvalues are correct and ordered for indices 1, 2, ..., ierr-1, but may not be the smallest eigenvalues.
This routine is a translation of the Algol procedure tql1() from ``The QR and QL Algorithms for Symmetric Matrices'', Numerische Mathematik 11, 293--306 (1968), by H. J. Bowdler, R. S. Martin, C. Reinsch and J. H. Wilkinson. That article was republished in the Handbook for Automatic Computation, Vol. II, Linear Algebra, 227--240 (1971), eds. J. H. Wilkinson and C. Reinsch, Springer-Verlag, ISBN 3-540-05414-6.
tql1() is part of the EISPACK-1 and EISPACK-2 libraries.
Algorithm xxx: Quadruple-Precision Gamma(x) and psi(x) Functions for Real Argumentsin ACM Transactions on Mathematical Software, Volume ??, Number ??, Pages ????--???? and ????--????, 2001, by
andNelson H. F. Beebe Center for Scientific Computing University of Utah Department of Mathematics, 110 LCB 155 S 1400 E RM 233 Salt Lake City, UT 84112-0090 Tel: +1 801 581 5254 FAX: +1 801 581 4148 Email: beebe@math.utah.edu, beebe@acm.org, beebe@computer.org WWW URL: http://www.math.utah.edu/~beebe
James S. Ball University of Utah Department of Physics Salt Lake City, UT 84112-0830 USA Tel: +1 801 581 8397 FAX: +1 801 581 6256 Email: ball@physics.utah.edu WWW URL: http://www.physics.utah.edu/people/faculty/ball.html