1 /*
2 * Mathlib : A C Library of Special Functions
3 * Copyright (C) 1998 Ross Ihaka
4 *
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 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, a copy is available at
17 * http://www.r-project.org/Licenses/
18 *
19 * SYNOPSIS
20 *
21 * #include <Rmath.h>
22 * double fsign(double x, double y);
23 *
24 * DESCRIPTION
25 *
26 * This function performs transfer of sign. The result is:
27 *
28 * |x| * signum(y)
29 */
30
31 #include "nmath.h"
32
fsign(double x,double y)33 double fsign(double x, double y)
34 {
35 #ifdef IEEE_754
36 if (ISNAN(x) || ISNAN(y))
37 return x + y;
38 #endif
39 return ((y >= 0) ? fabs(x) : -fabs(x));
40 }
41