/*
 * Program to test leapfrog LCG RNG.
 *
 * Command-line arguments are seed, number of samples, number of streams
 * (processes or threads for the Monte Carlo pi program).
 *
 * Notice that for a given seed and number of samples this should generate
 * the same results for any number of streams, and if it doesn't, something
 * is wrong!
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
#include "leapfrog-lcg.h"

int main(int argc, char* argv[]) {

    char* usage_msg = "arguments:  seed, number of sample, number of streams\n";
    
    if (argc < 3) {
        fprintf(stderr, usage_msg);
        return EXIT_FAILURE;
    }
    char *endptr;
    long seed = strtol(argv[1], &endptr, 10);
    if ((*endptr != '\0') || (seed < 1)) {
        fprintf(stderr, usage_msg);
        return EXIT_FAILURE;
    }
    long num_samples = strtol(argv[2], &endptr, 10);
    if ((*endptr != '\0') || (num_samples < 1)) {
        fprintf(stderr, usage_msg);
        return EXIT_FAILURE;
    }
    int num_streams = strtol(argv[3], &endptr, 10);
    if ((*endptr != '\0') || (num_streams < 1)) {
        fprintf(stderr, usage_msg);
        return EXIT_FAILURE;
    }

    rand_state_t rstates[num_streams];
    for (int i = 0; i < num_streams; ++i) {
        rand_init_state(num_streams, i, &rstates[i]);
        rand_set_seed(seed, &rstates[i]);
        printf("p %d, id %d, a %"PRId64", b %"PRId64", value %"PRId64"\n", 
                num_streams, i, 
                rstates[i].a, rstates[i].b, rstates[i].next_value);
    }

    int stream_id = 0;
    for (long i = 0; i < num_samples; ++i) {
        int64_t n = rand_next(&rstates[stream_id]);
        double d = (double) n / (double) RANDMAX;
        fprintf(stdout, "%20"PRId64" %17.15f\n", n, d);
        stream_id = (stream_id + 1) % num_streams;
    }
    return EXIT_SUCCESS;
}