randomUniformityTest/main.c

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <unistd.h>

#define CELLS_COUNT 3000
//#define EVENTS_MULTIPLIER 6

#if CELLS_COUNT > RAND_MAX
#	error CELLS_COUNT > RAND_MAX
#endif

int main(int argc, char *argv[]) {
	if (argc <= 1) {
		fprintf(stderr, "syntax: test events_multiplier\n");
		return -1;
	}

	int events_multiplier = atoi(argv[1]);

	long cells[CELLS_COUNT];
	memset(cells, 0, sizeof(cells));

	srand((unsigned) time(NULL) ^ getpid());

	for (int i = 0; i < CELLS_COUNT*events_multiplier; i++) {
		long value = rand() % CELLS_COUNT;
		cells[value]++;
	}

	long average    = events_multiplier;
	long derivation = 0;

	for (int i = 0; i < CELLS_COUNT; i++) {
		derivation += fabs(cells[i] - average);
		printf("% 4li", cells[i]);
		if ((i+1) % 50 == 0) {
			printf("\n");
		}
	}

	double average_derivation = ((double)derivation) / CELLS_COUNT;

	printf("\n\naverage:\t\t\t%li\naverage derivation:\t\t%lf\naverage relative derivation:\t%lf\n", average, average_derivation, average_derivation / average);

	return 0;
}