/*
 * 'test-square.c' created: Sat Oct 19 13:37:35 2002
 *
 * Copyright 2002 by Lubomir Host <8host AT pauli.fmph.uniba.sk>
 *
 * License: GNU GPL (GNU Public License)
 *
 * frekvencny test generatorov nahodnych cisel -- x^2 test dobrej zhody
 */

/* $Platon$ */

#ifdef HAV_CONFIG_H
#  include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>

#include "main.h"
#include "devices.h"
#include "tests.h"
#include "test-square.h"

RNG_test_t RNG_test_square = {
	"frequency x^2 test of generators", 2E9, test_square
};

int test_square(int *counts)
{
	int j = 0, k;
	int retval = RNG_OK;
	unsigned int cells;
	int *n_i;

	while (rng_devices[j] != NULL) {
		int i = 0;
		int cur = 1;
		int end = counts[0];
		Real_t random;
		Real_t T = 0.0;
		Real_t n_avg = 0.0;
		int index = 0;

		printf("# @@ running test for R.N.G. %s\n", (*rng_devices[j]).desc);
		printf("# ** <count>	<seconds>	<microseconds>	<numbers per second>\n");

		cells = ((unsigned int) (*rng_devices[j]).range >> (*rng_devices[j]).cell_count);
		n_i = calloc(cells, sizeof(int));
		if (n_i == NULL) {
			fprintf(stderr, "Allocation of %d int's failed!\n", cells);
			return RNG_FAIL;
		}
		/*
		else {
			fprintf(stderr, "Allocating of %d int's OK\n", cells);
		}
		*/

		while (counts[i] != -1
				&& end != -1
				&& counts[i] <= RNG_test_square.max_count
				&& counts[i] <= (*rng_devices[j]).max_count
				&& retval == RNG_OK) {
			end = counts[i];
			while ((cur - 1) != end && end != -1) {
				/* printf("cur = %d end = %d\n", cur, end); */

				random = (*rng_devices[j]).read();

				if ((*rng_devices[j]).cell_count != 0)
					index  = (unsigned int) random >> (*rng_devices[j]).cell_count;
				else index = (unsigned int) random;
				/*
				if (j==1)
					printf("random = %Lg\trandom_int = %d\tindex = %d\t\n",
							random, (int) random, index);
				*/

				n_i[index]++; /* increment counter for this cell */
				/*
				if (j==1)
					printf("Incremented n_i[%d] = %d\n", index, n_i[index]);
				*/
				cur++;
			}

			/* here we are looking for parameter
			 * T = Sum((n_j - n * p_j)^2 / (n * p_j)) =
			 *   = (Sum(n_j^2) / (n * p_j)  -  n)
			 * predpokladame rovnomerne rozdelenie,
			 * p_j = p = konst.
			 */
			T     = 0.0;
			n_avg = (1.0 * counts[i]) / cells;
			for (k = 0; k < cells; k++) {
				T += (n_i[k] -n_avg) * (n_i[k] -n_avg);
				/*
				if (j == 1)
					printf("%d ", n_i[k]);
				*/
			}
			T = T / n_avg;

			printf("%d\t%Lg\n", counts[i], T);
			end = counts[++i + 1];
		}
		j++; /* go to the next device ... */


		free(n_i);
	}

	return retval;
}

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