blob: 7d2620ff9fe18868ec534c5b4da2612abfa234b7 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
#include <stdint.h>
#include <math.h>
/****************************
** RANDOM NUMBER GENERATOR **
*****************************
** This is a second-order linear congruential random number
** generator. Its advantage is (of course) that it can be
** seeded and will thus produce repeatable sequences of
** random numbers.
*/
/****************************
* randnum() *
*****************************
** Second order linear congruential generator.
** Constants suggested by J. G. Skellam.
** If val==0, returns next member of sequence.
** val!=0, restart generator.
*/
int32_t randnum(int32_t val) {
static int32_t randw[2] = { 13 , 117 };
int32_t interm;
if (val != 0) {
randw[0] = 13;
randw[1] = 117;
}
interm = (randw[0]* (int32_t)254754 + randw[1]*(int32_t)529562) % (int32_t)999563;
randw[1] = randw[0];
randw[0] = interm;
return(interm);
}
/****************************
* randwc() *
*****************************
** Returns signed 32-bit random modulo num.
*/
int32_t randwc(int32_t num) {
return(randnum(0) % num);
}
/***************************
** abs_randwc() **
****************************
** Same as randwc(), only this routine returns only
** positive numbers.
*/
uint32_t abs_randwc(uint32_t num) {
return abs(randwc(num));
}
|
