| /* blas/source_rotg.h |
| * |
| * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or (at |
| * your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| */ |
| |
| { |
| const BASE roe = (fabs(*a) > fabs(*b) ? *a : *b); |
| const BASE scale = fabs(*a) + fabs(*b); |
| BASE r, z; |
| |
| if (scale != 0.0) { |
| const BASE aos = *a / scale; |
| const BASE bos = *b / scale; |
| r = scale * sqrt(aos * aos + bos * bos); |
| r = GSL_SIGN(roe) * r; |
| *c = *a / r; |
| *s = *b / r; |
| z = 1.0; |
| if (fabs(*a) > fabs(*b)) |
| z = *s; |
| if (fabs(*b) >= fabs(*a) && *c != 0.0) |
| z = 1.0 / (*c); |
| } else { |
| *c = 1.0; |
| *s = 0.0; |
| r = 0.0; |
| z = 0.0; |
| } |
| |
| *a = r; |
| *b = z; |
| } |
