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greg |
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/* Copyright (c) 1991 Regents of the University of California */
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#ifndef lint
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static char SCCSid[] = "$SunId$ LBL";
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#endif
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/*
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* Generate an N-dimensional Peano space-filling curve
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* on the interval [0,1).
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*
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* 12 Aug 91 Greg Ward
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*/
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extern double floor();
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static double
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peanoC(n, t, e) /* compute Peano coordinate */
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int n;
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double t, e;
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{
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register int i;
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double d;
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if (e >= 1./3.)
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return(t);
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d = 0.;
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while (t-d >= 1./3.)
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d += 1./3.;
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i = n;
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while (--i > 0)
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t *= 3.;
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t = 3.*(t - floor(t));
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i = 0;
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while (t >= 1.) {
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t -= 1.;
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i ^= 1;
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}
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t = peanoC(n, t, 3.*e);
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if (i)
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t = 1. - t;
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return(d + t/3.);
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}
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peano(p, n, t, e) /* compute Peano point */
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double p[];
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int n;
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double t, e;
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{
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register int i;
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int neg = 0;
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i = n;
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while (i-- > 0) {
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p[i] = peanoC(n, t, e);
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if (neg)
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p[i] = 1. - p[i];
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t *= 3.;
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while (t >= 1.) {
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t -= 1.;
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neg ^= 1;
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}
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}
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}
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