#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/times.h>
#include <unistd.h>

#ifndef COLMAJOR
#define COLMAJOR 0
#else
#undef  COLMAJOR
#define COLMAJOR 1
#endif

#ifndef MAXDIM_M
#define MAXDIM_M    4000
#endif

#ifndef MAXDIM_N
#define MAXDIM_N    4000
#endif

#ifndef MAXDIM_K
#define MAXDIM_K    4000
#endif

#ifndef MIN_M
#define MIN_M   100
#endif

#ifndef MIN_N
#define MIN_N   100
#endif

#ifndef MIN_K
#define MIN_K   100
#endif

#ifndef MAX_M
#define MAX_M   4000
#endif

#ifndef MAX_N
#define MAX_N   4000
#endif

#ifndef MAX_K
#define MAX_K   4000
#endif

#ifndef INC_M
#define INC_M   100
#endif

#ifndef INC_N
#define INC_N   100
#endif

#ifndef INC_K
#define INC_K   100
#endif

#ifndef ALPHA
#define ALPHA   1.0
#endif

#ifndef BETA
#define BETA    0.0
#endif

double A[MAXDIM_M*MAXDIM_K];
double B[MAXDIM_K*MAXDIM_N];

double C1[MAXDIM_M*MAXDIM_N];
double C2[MAXDIM_M*MAXDIM_N];
double C3[MAXDIM_M*MAXDIM_N];
double C4[MAXDIM_M*MAXDIM_N];

double
walltime()
{
   struct tms    ts;
   static double ClockTick=0.0;

   if (ClockTick==0.0) {
        ClockTick = 1.0 / ((double) sysconf(_SC_CLK_TCK));
   }
   return ((double) times(&ts)) * ClockTick;
}



void
initMatrix(long m, long n, double *A, long incRowA, long incColA)
{
    int i, j;
    for (j=0; j<n; ++j) {
        for (i=0; i<m; ++i) {
            A[i*incRowA+j*incColA] = ((double)rand() - RAND_MAX/2)*200/RAND_MAX;
        }
    }
}

void
dgecopy(long m, long n,
        const double *A, long incRowA, long incColA,
        double *B, long incRowB, long incColB)
{
    int i, j;
    for (j=0; j<n; ++j) {
        for (i=0; i<m; ++i) {
            B[i*incRowB+j*incColB] = A[i*incRowA+j*incColA];
        }
    }
}

void
dgeaxpy(long m, long n,
        double alpha,
        const double *X, long incRowX, long incColX,
        double       *Y, long incRowY, long incColY)
{
    long i, j;

    for (i=0; i<m; ++i) {
        for (j=0; j<n; ++j) {
            Y[i*incRowY+j*incColY] += alpha*X[i*incRowX+j*incColX];
        }
    }
}


double
asumDiffMatrix(long m, long n,
               const double *A, long incRowA, long incColA,
               double *B, long incRowB, long incColB)
{
    int i, j;

    double asum = 0;

    for (j=0; j<n; ++j) {
        for (i=0; i<m; ++i) {
            asum += fabs(B[i*incRowB+j*incColB] - A[i*incRowA+j*incColA]);
        }
    }
    return asum;
}

//------------------------------------------------------------------------------
// 1. GEMM Variante: Schulmethode
//------------------------------------------------------------------------------


//------------------------------------------------------------------------------
// 2. GEMM Variante: Zeilenweise
//------------------------------------------------------------------------------


//------------------------------------------------------------------------------
// 3. GEMM Variante: Spaltenweise
//------------------------------------------------------------------------------


//------------------------------------------------------------------------------
// 4. GEMM Variante: Bisschen mit Puffer
//------------------------------------------------------------------------------

int
main()
{
    initMatrix(MAXDIM_M, MAXDIM_K, A, 1, MAXDIM_M);
    initMatrix(MAXDIM_K, MAXDIM_N, B, 1, MAXDIM_K);
    initMatrix(MAXDIM_M, MAXDIM_N, C1, 1, MAXDIM_M);
    dgecopy(MAXDIM_M, MAXDIM_N, C1, 1, MAXDIM_M, C2, 1, MAXDIM_M);
    dgecopy(MAXDIM_M, MAXDIM_N, C1, 1, MAXDIM_M, C3, 1, MAXDIM_M);
    dgecopy(MAXDIM_M, MAXDIM_N, C1, 1, MAXDIM_M, C4, 1, MAXDIM_M);

    long m, n, k;

    // Header-Zeile für die Ausgabe

    for (m = MIN_M, n = MIN_N, k = MIN_K;
         m <=MAX_M && n <= MAX_N && k <= MAX_K;
         m += INC_M, n += INC_N, k += INC_K)
    {
        double t0, t1, t2, t3, t4;

        long incRowA = (COLMAJOR) ? 1 : k;
        long incColA = (COLMAJOR) ? m : 1;

        long incRowB = (COLMAJOR) ? 1 : n;
        long incColB = (COLMAJOR) ? k : 1;

        long incRowC = (COLMAJOR) ? 1 : n;
        long incColC = (COLMAJOR) ? m : 1;

        t0 = walltime();
        // GEMM Variante 1 hier aufrufen
        t1 = walltime() - t0;


        // Weitere Varianten aufrufen ....


        // Audgabe: Dimensionen, Zeit, MFLOPS, ...

    }
}