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/*

 *  Mathlib : A C Library of Special Functions

 *  Copyright (C) 1998 Ross Ihaka

 *

 *  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, a copy is available at

 *  http://www.r-project.org/Licenses/

 *

 *  SYNOPSIS

 *

 *    #include <Rmath.h>

 *    double fsign(double x, double y);

 *

 *  DESCRIPTION

 *

 *    This function performs transfer of sign.  The result is:

 *

 *                        |x| * signum(y)

 */

#include "nmath.h"

double fsign(double x, double y)

{

#ifdef IEEE_754

    if (ISNAN(x) || ISNAN(y))

	return x + y;

#endif

    return ((y >= 0) ? fabs(x) : -fabs(x));

}