1 /*
2 * Normal distribution table generator
3 * Taken from the uncopyrighted NISTnet code.
4 */
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <math.h>
8 #include <string.h>
9 #include <limits.h>
10
11 #include <linux/types.h>
12 #include <linux/pkt_sched.h>
13
14 #define TABLESIZE 16384
15 #define TABLEFACTOR NETEM_DIST_SCALE
16
17 static double
normal(double x,double mu,double sigma)18 normal(double x, double mu, double sigma)
19 {
20 return .5 + .5*erf((x-mu)/(sqrt(2.0)*sigma));
21 }
22
23
24 int
main(int argc,char ** argv)25 main(int argc, char **argv)
26 {
27 int i, n;
28 double x;
29 double table[TABLESIZE+1];
30
31 for (x = -10.0; x < 10.05; x += .00005) {
32 i = rint(TABLESIZE * normal(x, 0.0, 1.0));
33 table[i] = x;
34 }
35
36
37 printf("# This is the distribution table for the normal distribution.\n");
38 for (i = n = 0; i < TABLESIZE; i += 4) {
39 int value = (int) rint(table[i]*TABLEFACTOR);
40 if (value < SHRT_MIN) value = SHRT_MIN;
41 if (value > SHRT_MAX) value = SHRT_MAX;
42
43 printf(" %d", value);
44 if (++n == 8) {
45 putchar('\n');
46 n = 0;
47 }
48 }
49
50 return 0;
51 }
52