ack/lang/cem/libcc/math/hypot.c

/*
 * (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 *
 * Author: Ceriel J.H. Jacobs
 */

/* $Id$ */

double
hypot(x,y)
	double x,y;
{
	/*	Computes sqrt(x*x+y*y), avoiding overflow */

	extern double sqrt();

	if (x < 0) x = -x;
	if (y < 0) y = -y;
	if (x > y) {
		double t = y;
		y = x;
		x = t;
	}
	/* sqrt(x*x+y*y) = sqrt(y*y*(x*x/(y*y)+1.0)) = y*sqrt(x*x/(y*y)+1.0) */
	x /= y;
	return y*sqrt(x*x+1.0);
}

struct complex {
	double r,i;
};

double
cabs(p_compl)
	struct complex p_compl;
{
	return hypot(p_compl.r, p_compl.i);
}