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greg |
1.1 |
#ifndef lint |
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greg |
2.7 |
static const char RCSid[] = "$Id: multisamp.c,v 2.6 2024/04/17 15:07:29 greg Exp $"; |
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greg |
1.1 |
#endif |
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/* |
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* Binary space partitioning curve for multidimensional sampling. |
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* |
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* Written by Christophe Schlick |
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*/ |
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greg |
2.4 |
#include "copyright.h" |
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schorsch |
2.5 |
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#include <stdlib.h> |
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greg |
2.3 |
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#include "random.h" |
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greg |
2.6 |
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/* Convert 1-dimensional sample to N dimensions */ |
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greg |
2.3 |
void |
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greg |
2.6 |
multisamp(double t[], int n, double r) |
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greg |
1.1 |
{ |
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int j; |
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greg |
2.6 |
int i, k; |
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greg |
1.1 |
int ti[8]; |
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double s; |
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greg |
2.7 |
while (n > 8) |
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t[--n] = frandom(); |
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greg |
1.1 |
i = n; |
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while (i-- > 0) |
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ti[i] = 0; |
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j = 8; |
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while (j--) { |
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k = s = r*(1<<n); |
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r = s - k; |
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i = n; |
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while (i-- > 0) |
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ti[i] += ti[i] + ((k>>i) & 1); |
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} |
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i = n; |
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while (i-- > 0) |
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greg |
2.6 |
t[i] = (1./256.) * (ti[i] + frandom()); |
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greg |
1.1 |
} |
