1#include <stdio.h>
2#include <stdlib.h>
3#include <inttypes.h>
4#include <assert.h>
5#include <math.h>
6#include <string.h>
7
8#include "../lib/types.h"
9#include "../log.h"
10#include "../lib/lfsr.h"
11#include "../lib/axmap.h"
12#include "../smalloc.h"
13#include "../minmax.h"
14#include "../lib/rand.h"
15
16int main(int argc, char *argv[])
17{
18	struct frand_state s;
19	uint64_t i, start, end, nvalues;
20	unsigned long *buckets, index, pass, fail;
21	double p, dev, mean, vmin, vmax;
22
23	if (argc < 4) {
24		log_err("%s: start end nvalues\n", argv[0]);
25		return 1;
26	}
27
28	start = strtoul(argv[1], NULL, 10);
29	end = strtoul(argv[2], NULL, 10);
30
31	if (start >= end) {
32		log_err("%s: start must be smaller than end\n", argv[0]);
33		return 1;
34	}
35	index = 1 + end - start;
36	buckets = calloc(index, sizeof(unsigned long));
37
38	nvalues = strtoul(argv[3], NULL, 10);
39
40	init_rand(&s, false);
41
42	for (i = 0; i < nvalues; i++) {
43		int v = rand32_between(&s, start, end);
44
45		buckets[v - start]++;
46	}
47
48	p = 1.0 / index;
49	dev = sqrt(nvalues * p * (1.0 - p));
50	mean = nvalues * p;
51	vmin = mean - dev;
52	vmax = mean + dev;
53
54	pass = fail = 0;
55	for (i = 0; i < index; i++) {
56		if (buckets[i] < vmin || buckets[i] > vmax) {
57			printf("FAIL bucket%4lu: val=%8lu (%.1f < %.1f > %.1f)\n", (unsigned long) i + 1, buckets[i], vmin, mean, vmax);
58			fail++;
59		} else {
60			printf("PASS bucket%4lu: val=%8lu (%.1f < %.1f > %.1f)\n", (unsigned long) i + 1, buckets[i], vmin, mean, vmax);
61			pass++;
62		}
63	}
64
65	printf("Passes=%lu, Fail=%lu\n", pass, fail);
66
67	return 0;
68}
69