3 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Gerard Jungman, Brian Gough
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 3 of the License, or (at
8 * your option) any later version.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 /* Generate a Givens rotation (cos,sin) which takes v=(x,y) to (|v|,0)
22 From Golub and Van Loan, "Matrix Computations", Section 5.1.8 */
25 create_givens (const double a, const double b, double *c, double *s)
32 else if (fabs (b) > fabs (a))
35 double s1 = 1.0 / sqrt (1 + t * t);
42 double c1 = 1.0 / sqrt (1 + t * t);