/* * (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 struct complex { double r,i; }; _PROTOTYPE(double hypot, (double x, double y )); _PROTOTYPE(double cabs, (struct complex p_compl )); /* $Header: /cvsup/minix/src/lib/other/hypot.c,v 1.1.1.1 2005/04/21 14:56:27 beng Exp $ */ 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); }