| 1 |
– |
/* Copyright (c) 1991 Regents of the University of California */ |
| 2 |
– |
|
| 1 |
|
#ifndef lint |
| 2 |
< |
static char SCCSid[] = "$SunId$ LBL"; |
| 2 |
> |
static const char RCSid[] = "$Id$"; |
| 3 |
|
#endif |
| 6 |
– |
|
| 4 |
|
/* |
| 5 |
< |
* Uncorrelated (anticorrelated) random function |
| 5 |
> |
* Anticorrelated random function due to Christophe Schlick |
| 6 |
|
*/ |
| 7 |
|
|
| 8 |
+ |
#include "copyright.h" |
| 9 |
+ |
|
| 10 |
+ |
#include "standard.h" |
| 11 |
|
#include "random.h" |
| 12 |
|
|
| 13 |
< |
#define NULL 0 |
| 13 |
> |
#undef initurand |
| 14 |
|
|
| 15 |
< |
extern char *malloc(); |
| 15 |
> |
#define MAXORDER (8*sizeof(unsigned short)) |
| 16 |
|
|
| 17 |
< |
short *urperm; /* urand() permutation */ |
| 18 |
< |
int urmask; /* bits used in permutation */ |
| 17 |
> |
static unsigned short empty_tab = 0; |
| 18 |
|
|
| 19 |
+ |
unsigned short *urperm = &empty_tab; /* urand() permutation */ |
| 20 |
+ |
int urmask = 0; /* bits used in permutation */ |
| 21 |
|
|
| 22 |
< |
initurand(size) /* initialize urand() for size entries */ |
| 23 |
< |
int size; |
| 22 |
> |
|
| 23 |
> |
int |
| 24 |
> |
initurand( /* initialize urand() for size entries */ |
| 25 |
> |
int size |
| 26 |
> |
) |
| 27 |
|
{ |
| 28 |
|
int order, n; |
| 29 |
< |
register int i, offset; |
| 29 |
> |
int i, offset; |
| 30 |
|
|
| 31 |
< |
size--; |
| 32 |
< |
for (i = 1; size >>= 1; i++) |
| 33 |
< |
; |
| 31 |
> |
if ((urperm != NULL) & (urperm != &empty_tab)) |
| 32 |
> |
free((void *)urperm); |
| 33 |
> |
if (--size <= 0) { |
| 34 |
> |
empty_tab = 0; |
| 35 |
> |
urperm = &empty_tab; |
| 36 |
> |
urmask = 0; |
| 37 |
> |
return(0); |
| 38 |
> |
} |
| 39 |
> |
for (i = 1; (size >>= 1); i++) |
| 40 |
> |
if (i == MAXORDER) |
| 41 |
> |
break; |
| 42 |
|
order = i; |
| 43 |
< |
urmask = (1<<i) - 1; |
| 44 |
< |
urperm = (short *)malloc((urmask+1)*sizeof(short)); |
| 43 |
> |
urmask = (1<<order) - 1; |
| 44 |
> |
urperm = (unsigned short *)malloc((urmask+1)*sizeof(unsigned short)); |
| 45 |
|
if (urperm == NULL) { |
| 46 |
|
eputs("out of memory in initurand\n"); |
| 47 |
|
quit(1); |
| 49 |
|
urperm[0] = 0; |
| 50 |
|
for (n = 1, offset = 1; n <= order; n++, offset <<= 1) |
| 51 |
|
for (i = offset; i--; ) { |
| 52 |
< |
urperm[i] = |
| 41 |
< |
urperm[i+offset] = 2*urperm[i]; |
| 52 |
> |
urperm[i+offset] = urperm[i] <<= 1; |
| 53 |
|
if (random() & 0x4000) |
| 54 |
|
urperm[i]++; |
| 55 |
|
else |
| 56 |
|
urperm[i+offset]++; |
| 57 |
|
} |
| 58 |
+ |
return(urmask+1); |
| 59 |
+ |
} |
| 60 |
+ |
|
| 61 |
+ |
|
| 62 |
+ |
int |
| 63 |
+ |
ilhash( /* hash a set of integer values */ |
| 64 |
+ |
int *d, |
| 65 |
+ |
int n |
| 66 |
+ |
) |
| 67 |
+ |
{ |
| 68 |
+ |
static int tab[8] = {103699,96289,73771,65203,81119,87037,92051,98899}; |
| 69 |
+ |
int hval; |
| 70 |
+ |
|
| 71 |
+ |
hval = 0; |
| 72 |
+ |
while (n-- > 0) |
| 73 |
+ |
hval ^= *d++ * tab[n&7]; |
| 74 |
+ |
return(hval & 0x7fffffff); |
| 75 |
|
} |
