#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <stdio.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <math.h>
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char *pname;
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char *in_file;
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#define DATA_COUNT (1024*1024)
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double data_items[DATA_COUNT];
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int num_data_items = 0;
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#define BUFSIZE 1024
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char in_buf[BUFSIZE];
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static int
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compare_double(const void *p1, const void *p2)
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{
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double val1 = *(u_int64_t *)p1;
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double val2 = *(u_int64_t *)p2;
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if (val1 == val2)
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return 0;
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if (val1 < val2)
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return -1;
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return 1;
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}
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int
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main(int argc, char **argv)
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{
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FILE *in_fp;
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double sum_x = 0;
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double sum_sq_x = 0;
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double mean;
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double std_dev;
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int i;
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int one_sd = 0;
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int two_sd = 0;
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int three_sd = 0;
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double one_sd_low, one_sd_high;
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double two_sd_low, two_sd_high;
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double three_sd_low, three_sd_high;
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pname = argv[0];
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if (argc == 1)
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in_fp = stdin;
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else {
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in_file = argv[1];
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in_fp = fopen(in_file, "r");
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}
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while (fgets(in_buf, BUFSIZE, in_fp)) {
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if (num_data_items == DATA_COUNT) {
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fprintf(stderr,
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"DATA overflow, increase size of data_items array\n");
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exit(1);
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}
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sscanf(in_buf, "%lf", &data_items[num_data_items]);
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#if 0
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printf("%lf\n", data_items[num_data_items]);
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#endif
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num_data_items++;
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}
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if (num_data_items == 0) {
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fprintf(stderr, "Empty input file ?\n");
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exit(1);
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}
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#if 0
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printf("Total items %lu\n", num_data_items);
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#endif
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for (i = 0 ; i < num_data_items ; i++) {
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sum_x += data_items[i];
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sum_sq_x += data_items[i] * data_items[i];
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}
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mean = sum_x / num_data_items;
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printf("\tMean %.4f\n", mean);
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std_dev = sqrt((sum_sq_x / num_data_items) - (mean * mean));
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printf("\tStd Dev %.4f (%.4f%% of mean)\n",
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std_dev, (std_dev * 100.0) / mean);
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one_sd_low = mean - std_dev;
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one_sd_high = mean + std_dev;
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two_sd_low = mean - (2 * std_dev);
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two_sd_high = mean + (2 * std_dev);
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three_sd_low = mean - (3 * std_dev);
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three_sd_high = mean + (3 * std_dev);
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for (i = 0 ; i < num_data_items ; i++) {
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if (data_items[i] >= one_sd_low &&
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data_items[i] <= one_sd_high)
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one_sd++;
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if (data_items[i] >= two_sd_low &&
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data_items[i] <= two_sd_high)
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two_sd++;
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if (data_items[i] >= three_sd_low &&
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data_items[i] <= three_sd_high)
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three_sd++;
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}
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printf("\tWithin 1 SD %.2f%%\n",
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((double)one_sd * 100) / num_data_items);
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printf("\tWithin 2 SD %.2f%%\n",
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((double)two_sd * 100) / num_data_items);
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printf("\tWithin 3 SD %.2f%%\n",
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((double)three_sd* 100) / num_data_items);
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printf("\tOutside 3 SD %.2f%%\n",
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((double)(num_data_items - three_sd) * 100) / num_data_items);
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/* Sort the data to get percentiles */
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qsort(data_items, num_data_items, sizeof(u_int64_t), compare_double);
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printf("\t50th percentile %lf\n", data_items[num_data_items / 2]);
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printf("\t75th percentile %lf\n", data_items[(3 * num_data_items) / 4]);
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printf("\t90th percentile %lf\n", data_items[(9 * num_data_items) / 10]);
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printf("\t99th percentile %lf\n", data_items[(99 * num_data_items) / 100]);
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}
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