/*
    mat1bench

    Written by Scott Robert Ladd.
    No rights reserved. This is public domain software, for use by anyone.

    A number-crunching benchmark that can be used as a fitness test for
    evolving optimal compiler options via genetic algorithm.
    
    Nothing special here -- just a brute-force matrix multiply.

    Note that the code herein is design for the purpose of testing 
    computational performance; error handling and other such "niceties"
    is virtually non-existent.

    Actual benchmark results can be found at:
            http://www.coyotegulch.com

    Please do not use this information or algorithm in any way that might
    upset the balance of the universe or otherwise result in gastric upset.
*/

#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

// adjust size of test for environment
//static const int N = 600;
#define N 600

// embedded random number generator; ala Park and Miller
static       int32_t seed = 1325;
static const int32_t IA   = 16807;
static const int32_t IM   = 2147483647;
static const double  AM   = 4.65661287525E-10;
static const int32_t IQ   = 127773;
static const int32_t IR   = 2836;
static const int32_t MASK = 123459876;

static double random_double()
{
    int32_t k;
    double result;
    
    seed ^= MASK;
    k = seed / IQ;
    seed = IA * (seed - k * IQ) - IR * k;
    
    if (seed < 0)
        seed += IM;
    
    result = AM * seed;
    seed ^= MASK;
    
    return result;
}

double a[N][N];
double b[N][N];
double c[N][N];

int main(int argc, char * argv[])
{
    // general purpose indices
    int i, j, k;
    
    // do we have verbose output?
    bool   ga_testing = false;
    
    if (argc > 1)
    {
        for (i = 1; i < argc; ++i)
        {
            if (!strcmp(argv[i],"-ga"))
            {
                ga_testing = true;
                break;
            }
        }
    }
    
    for (i = 0; i < N; ++i)
    {
        for (j = 0; j < N; ++j)
        {
            a[i][j] = random_double();
            b[i][j] = random_double();
            c[i][j] = 0.0;
        }
    }
    
    // get starting time    
    struct timespec start, stop;
    clock_gettime(CLOCK_REALTIME,&start);
    
    // generate mandelbrot set
    for (i = 0; i < N; ++i)
    {
        for (j = 0; j < N; ++j)
        {
            for (k = 0; k < N; ++k)
            {
                c[i][j] = c[i][j] + a[i][k] * b[k][j];
            }
        }
    }

    // get final time
    clock_gettime(CLOCK_REALTIME,&stop);        
    double run_time = (stop.tv_sec - start.tv_sec) + (double)(stop.tv_nsec - start.tv_nsec) / 1000000000.0;

    // report runtime
    if (ga_testing)
        fprintf(stdout,"%f",run_time);
    else        
        fprintf(stdout,"mat1bench (Std. C) run time: %f\n",run_time);
    
    fflush(stdout);

    // done    
    return 0;
}