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- /* sys/hypot.c
- *
- * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Gerard Jungman, Brian Gough, Patrick Alken
- *
- * 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 3 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.
- */
- #include "gsl__config.h"
- #include <math.h>
- #include "gsl_math.h"
- double gsl_hypot (const double x, const double y);
- double gsl_hypot3 (const double x, const double y, const double z);
- double gsl_hypot (const double x, const double y)
- {
- double xabs = fabs(x) ;
- double yabs = fabs(y) ;
- double min, max;
- if (xabs < yabs) {
- min = xabs ;
- max = yabs ;
- } else {
- min = yabs ;
- max = xabs ;
- }
- if (min == 0)
- {
- return max ;
- }
- {
- double u = min / max ;
- return max * sqrt (1 + u * u) ;
- }
- }
- double
- gsl_hypot3(const double x, const double y, const double z)
- {
- double xabs = fabs(x);
- double yabs = fabs(y);
- double zabs = fabs(z);
- double w = GSL_MAX(xabs, GSL_MAX(yabs, zabs));
- if (w == 0.0)
- {
- return (0.0);
- }
- else
- {
- double r = w * sqrt((xabs / w) * (xabs / w) +
- (yabs / w) * (yabs / w) +
- (zabs / w) * (zabs / w));
- return r;
- }
- }
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