43 lines
767 B
C
43 lines
767 B
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
|
|
*/
|
|
|
|
#include <math.h>
|
|
|
|
struct complex {
|
|
double r,i;
|
|
};
|
|
|
|
_PROTOTYPE(double hypot, (double x, double y ));
|
|
_PROTOTYPE(double cabs, (struct complex p_compl ));
|
|
|
|
/* $Header$ */
|
|
|
|
double
|
|
hypot(x, y)
|
|
double x, y;
|
|
{
|
|
/* Computes sqrt(x*x+y*y), avoiding overflow */
|
|
|
|
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) */
|
|
if (y == 0.0) return 0.0;
|
|
x /= y;
|
|
return y*sqrt(x*x+1.0);
|
|
}
|
|
|
|
double
|
|
cabs(p_compl)
|
|
struct complex p_compl;
|
|
{
|
|
return hypot(p_compl.r, p_compl.i);
|
|
}
|