47 lines
783 B
C
47 lines
783 B
C
/*
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* (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*
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* Author: Ceriel J.H. Jacobs
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*/
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#include <math.h>
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struct complex {
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double r,i;
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};
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_PROTOTYPE(double hypot, (double x, double y ));
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/* $Header$ */
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double
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hypot(double x, double y)
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{
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/* Computes sqrt(x*x+y*y), avoiding overflow */
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if (x < 0) x = -x;
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if (y < 0) y = -y;
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if (x > y) {
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double t = y;
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y = x;
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x = t;
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}
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/* sqrt(x*x+y*y) = sqrt(y*y*(x*x/(y*y)+1.0)) = y*sqrt(x*x/(y*y)+1.0) */
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if (y == 0.0) return 0.0;
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x /= y;
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return y*sqrt(x*x+1.0);
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}
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#if 0
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_PROTOTYPE(double cabs, (struct complex p_compl ));
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double
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cabs(p_compl)
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struct complex p_compl;
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{
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return hypot(p_compl.r, p_compl.i);
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}
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#endif
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