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

#ifndef 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   7000
#endif

#ifndef MAX_N
#define MAX_N   7000
#endif

#ifndef MAX_K
#define MAX_K   7000
#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   1.5
#endif

#ifndef BETA
#define BETA    1.5
#endif


//==============================================================================
// bench
//==============================================================================


//------------------------------------------------------------------------------
// Auxiliary data for benchmarking
//------------------------------------------------------------------------------


double A_bench[MAXDIM_M*MAXDIM_K];
double B_bench[MAXDIM_K*MAXDIM_N];

double C1_bench[MAXDIM_M*MAXDIM_N];
double C2_bench[MAXDIM_M*MAXDIM_N];

//------------------------------------------------------------------------------
// Auxiliary functions for benchmarking
//------------------------------------------------------------------------------

double
walltime_bench()
{
   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_bench(long m, long n, double *A, long incRowA, long incColA)
{
    long 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;
        }
    }
}

double
dasumDiffMatrix_bench(long m, long n,
                      const double *A, long incRowA, long incColA,
                      double *B, long incRowB, long incColB)
{
    long 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;
}


//==============================================================================
// ulmBLAS
//==============================================================================

//------------------------------------------------------------------------------
// A <- B
//------------------------------------------------------------------------------

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

//------------------------------------------------------------------------------
// Y <- Y + alpha*Y
//------------------------------------------------------------------------------

void
dgeaxpy_ulmBLAS(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];
        }
    }
}

//------------------------------------------------------------------------------
// A <- alpha * A
//------------------------------------------------------------------------------

void
dgescal_ulmBLAS(long m, long n,
                double alpha,
                double *X, long incRowX, long incColX)
{
    long i, j;

    if (alpha!=1.0) {
        for (i=0; i<m; ++i) {
            for (j=0; j<n; ++j) {
                X[i*incRowX+j*incColX] *= alpha;
            }
        }
    }
}

//==============================================================================
// refColMajor
//==============================================================================

void
dgemm_refColMajor(long m, long n, long k,
                  double alpha,
                  const double *A, long incRowA, long incColA,
                  const double *B, long incRowB, long incColB,
                  double beta,
                  double *C, long incRowC, long incColC)
{
    long i, j, l;

    dgescal_ulmBLAS(m, n, beta, C, incRowC, incColC);
    for (j=0; j<n; ++j) {
        for (l=0; l<k; ++l) {
            for (i=0; i<m; ++i) {
                C[i*incRowC+j*incColC] += alpha*A[i*incRowA+l*incColA]
                                               *B[l*incRowB+j*incColB];
            }
        }
    }
}

//==============================================================================
// simpleBuffer
//==============================================================================

#ifndef SIMPLE_PUFFER_MC
#define SIMPLE_PUFFER_MC 256
#endif

#ifndef SIMPLE_PUFFER_KC
#define SIMPLE_PUFFER_KC 256
#endif

#ifndef SIMPLE_PUFFER_NC
#define SIMPLE_PUFFER_NC 1024
#endif

double A_simpleBuffer[SIMPLE_PUFFER_MC*SIMPLE_PUFFER_KC];
double B_simpleBuffer[SIMPLE_PUFFER_KC*SIMPLE_PUFFER_NC];
double C_simpleBuffer[SIMPLE_PUFFER_MC*SIMPLE_PUFFER_NC];

void
dgemm_simpleBuffer(long m, long n, long k,
                   double alpha,
                   const double *A, long incRowA, long incColA,
                   const double *B, long incRowB, long incColB,
                   double beta,
                   double *C, long incRowC, long incColC)
{
    long i, j, l;

    long MC = SIMPLE_PUFFER_MC;
    long NC = SIMPLE_PUFFER_NC;
    long KC = SIMPLE_PUFFER_KC;

    long mb = m / MC;
    long nb = n / NC;
    long kb = k / KC;

    long mr = m % MC;
    long nr = n % NC;
    long kr = k % KC;

    dgescal_ulmBLAS(m, n, beta, C, incRowC, incColC);

    for (j=0; j<=nb; ++j) {
        long N = (j<nb || nr==0) ? NC : nr;

        for (l=0; l<=kb; ++l) {
            long K = (l<kb || kr==0) ? KC : kr;

            dgecopy_ulmBLAS(K, N,
                            &B[l*KC*incRowB+j*NC*incColB], incRowB, incColB,
                            B_simpleBuffer, 1, KC);

            for (i=0; i<=mb; ++i) {
                long M = (i<mb || mr==0) ? MC : mr;

                dgecopy_ulmBLAS(M, K,
                                &A[i*MC*incRowA+l*KC*incColA], incRowA, incColA,
                                A_simpleBuffer, 1, MC);

                dgemm_refColMajor(M, N, K,
                                  1.0,
                                  A_simpleBuffer, 1, MC,
                                  B_simpleBuffer, 1, KC,
                                  0.0,
                                  C_simpleBuffer, 1, MC);

                dgeaxpy_ulmBLAS(M, N,
                                alpha,
                                C_simpleBuffer, 1, MC,
                                &C[i*MC*incRowC+j*NC*incColC], incRowC, incColC);
            }
        }
    }
}

int
main()
{
    initMatrix_bench(MAXDIM_M, MAXDIM_K, A_bench, 1, MAXDIM_M);
    initMatrix_bench(MAXDIM_K, MAXDIM_N, B_bench, 1, MAXDIM_K);
    initMatrix_bench(MAXDIM_M, MAXDIM_N, C1_bench, 1, MAXDIM_M);
    dgecopy_ulmBLAS(MAXDIM_M, MAXDIM_N,
                    C1_bench, 1, MAXDIM_M,
                    C2_bench, 1, MAXDIM_M);

    long m, n, k;

    // Header-Zeile für die Ausgabe
    printf("%5s %5s %5s ", "m", "n", "k");
    printf("%5s %5s ", "IRA", "ICA");
    printf("%5s %5s ", "IRB", "ICB");
    printf("%5s %5s ", "IRC", "ICC");
    printf("%20s %9s", "refColMajor: t", "MFLOPS");
    printf("%20s %9s %9s", "refSimpleBuffer: t", "MFLOPS", "diff");
    printf("\n");

    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, diff;

        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;

        printf("%5ld %5ld %5ld ", m, n, k);
        printf("%5ld %5ld ", incRowA, incColA);
        printf("%5ld %5ld ", incRowB, incColB);
        printf("%5ld %5ld ", incRowC, incColC);

        t0 = walltime_bench();
        dgemm_refColMajor(m, n, k, ALPHA,
                          A_bench, incRowA, incColA,
                          B_bench, incRowB, incColB,
                          BETA,
                          C1_bench, incRowC, incColC);
        t1 = walltime_bench() - t0;
        printf("%20.4lf %9.2lf", t1, 2.*m/1000*n/1000*k/t1);

        t0 = walltime_bench();
        dgemm_simpleBuffer(m, n, k, ALPHA,
                           A_bench, incRowA, incColA,
                           B_bench, incRowB, incColB,
                           BETA,
                           C2_bench, incRowC, incColC);
        t1 = walltime_bench() - t0;
        diff = dasumDiffMatrix_bench(m, n,
                                     C1_bench, incRowC, incColC,
                                     C2_bench, incRowC, incColC);
        printf("%20.4lf %9.2lf %9.1e", t1, 2.*m/1000*n/1000*k/t1, diff);
        printf("\n");
    }
    return 0;
}