85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
/*
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* Copyright (c) 1987 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted provided
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* that: (1) source distributions retain this entire copyright notice and
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* comment, and (2) distributions including binaries display the following
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* acknowledgement: ``This product includes software developed by the
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* University of California, Berkeley and its contributors'' in the
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* documentation or other materials provided with the distribution and in
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* all advertising materials mentioning features or use of this software.
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* Neither the name of the University nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)sincos.c 5.5 (Berkeley) 10/9/90";
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#endif /* not lint */
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#include "trig.h"
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double
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sin(x)
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double x;
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{
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double a,c,z;
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if(!finite(x)) /* sin(NaN) and sin(INF) must be NaN */
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return x-x;
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x=drem(x,PI2); /* reduce x into [-PI,PI] */
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a=copysign(x,one);
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if (a >= PIo4) {
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if(a >= PI3o4) /* ... in [3PI/4,PI] */
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x = copysign((a = PI-a),x);
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else { /* ... in [PI/4,3PI/4] */
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a = PIo2-a; /* rtn. sign(x)*C(PI/2-|x|) */
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z = a*a;
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c = cos__C(z);
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z *= half;
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a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
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return copysign(a,x);
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}
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}
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if (a < small) { /* rtn. S(x) */
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big+a;
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return x;
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}
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return x+x*sin__S(x*x);
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}
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double
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cos(x)
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double x;
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{
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double a,c,z,s = 1.0;
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if(!finite(x)) /* cos(NaN) and cos(INF) must be NaN */
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return x-x;
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x=drem(x,PI2); /* reduce x into [-PI,PI] */
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a=copysign(x,one);
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if (a >= PIo4) {
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if (a >= PI3o4) { /* ... in [3PI/4,PI] */
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a = PI-a;
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s = negone;
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}
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else { /* ... in [PI/4,3PI/4] */
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a = PIo2-a;
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return a+a*sin__S(a*a); /* rtn. S(PI/2-|x|) */
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}
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}
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if (a < small) {
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big+a;
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return s; /* rtn. s*C(a) */
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}
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z = a*a;
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c = cos__C(z);
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z *= half;
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a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
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return copysign(a,s);
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}
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