1 #include <fcntl.h>
2 #include <sys/ioctl.h>
3 #include <stdio.h>
4 #include <sys/time.h>
5 #include <sys/types.h>
6 #include <sys/mman.h>
7 #include <unistd.h>
8 #include <stdlib.h>
9 #include <math.h>
10
11 char *pname;
12 char *in_file;
13
14 #define DATA_COUNT (1024*1024)
15 double data_items[DATA_COUNT];
16
17 int num_data_items = 0;
18
19 #define BUFSIZE 1024
20 char in_buf[BUFSIZE];
21
22 static int
compare_double(const void * p1,const void * p2)23 compare_double(const void *p1, const void *p2)
24 {
25 double val1 = *(u_int64_t *)p1;
26 double val2 = *(u_int64_t *)p2;
27
28 if (val1 == val2)
29 return 0;
30 if (val1 < val2)
31 return -1;
32 return 1;
33 }
34
35 int
main(int argc,char ** argv)36 main(int argc, char **argv)
37 {
38 FILE *in_fp;
39 double sum_x = 0;
40 double sum_sq_x = 0;
41 double mean;
42 double std_dev;
43 int i;
44 int one_sd = 0;
45 int two_sd = 0;
46 int three_sd = 0;
47 double one_sd_low, one_sd_high;
48 double two_sd_low, two_sd_high;
49 double three_sd_low, three_sd_high;
50
51 pname = argv[0];
52 if (argc == 1)
53 in_fp = stdin;
54 else {
55 in_file = argv[1];
56 in_fp = fopen(in_file, "r");
57 }
58 while (fgets(in_buf, BUFSIZE, in_fp)) {
59 if (num_data_items == DATA_COUNT) {
60 fprintf(stderr,
61 "DATA overflow, increase size of data_items array\n");
62 exit(1);
63 }
64 sscanf(in_buf, "%lf", &data_items[num_data_items]);
65 #if 0
66 printf("%lf\n", data_items[num_data_items]);
67 #endif
68 num_data_items++;
69 }
70 if (num_data_items == 0) {
71 fprintf(stderr, "Empty input file ?\n");
72 exit(1);
73 }
74 #if 0
75 printf("Total items %lu\n", num_data_items);
76 #endif
77 for (i = 0 ; i < num_data_items ; i++) {
78 sum_x += data_items[i];
79 sum_sq_x += data_items[i] * data_items[i];
80 }
81 mean = sum_x / num_data_items;
82 printf("\tMean %.4f\n", mean);
83 std_dev = sqrt((sum_sq_x / num_data_items) - (mean * mean));
84 printf("\tStd Dev %.4f (%.4f%% of mean)\n",
85 std_dev, (std_dev * 100.0) / mean);
86 one_sd_low = mean - std_dev;
87 one_sd_high = mean + std_dev;
88 two_sd_low = mean - (2 * std_dev);
89 two_sd_high = mean + (2 * std_dev);
90 three_sd_low = mean - (3 * std_dev);
91 three_sd_high = mean + (3 * std_dev);
92 for (i = 0 ; i < num_data_items ; i++) {
93 if (data_items[i] >= one_sd_low &&
94 data_items[i] <= one_sd_high)
95 one_sd++;
96 if (data_items[i] >= two_sd_low &&
97 data_items[i] <= two_sd_high)
98 two_sd++;
99 if (data_items[i] >= three_sd_low &&
100 data_items[i] <= three_sd_high)
101 three_sd++;
102 }
103 printf("\tWithin 1 SD %.2f%%\n",
104 ((double)one_sd * 100) / num_data_items);
105 printf("\tWithin 2 SD %.2f%%\n",
106 ((double)two_sd * 100) / num_data_items);
107 printf("\tWithin 3 SD %.2f%%\n",
108 ((double)three_sd* 100) / num_data_items);
109 printf("\tOutside 3 SD %.2f%%\n",
110 ((double)(num_data_items - three_sd) * 100) / num_data_items);
111 /* Sort the data to get percentiles */
112 qsort(data_items, num_data_items, sizeof(u_int64_t), compare_double);
113 printf("\t50th percentile %lf\n", data_items[num_data_items / 2]);
114 printf("\t75th percentile %lf\n", data_items[(3 * num_data_items) / 4]);
115 printf("\t90th percentile %lf\n", data_items[(9 * num_data_items) / 10]);
116 printf("\t99th percentile %lf\n", data_items[(99 * num_data_items) / 100]);
117 }
118
119