Lösungsvorschlag

#ifndef HPC_ULMBLAS_H
#define HPC_ULMBLAS_H 1

namespace ulmBLAS {

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

template <typename T, typename Index>
void
gecopy(Index m, Index n,
       const T *A, Index incRowA, Index incColA,
       T *B, Index incRowB, Index incColB)
{
    for (Index j=0; j<n; ++j) {
        for (Index i=0; i<m; ++i) {
            B[i*incRowB+j*incColB] = A[i*incRowA+j*incColA];
        }
    }
}

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

template <typename T, typename Index>
void
geaxpy(Index m, Index n,
       T alpha,
       const T *X, Index incRowX, Index incColX,
       T       *Y, Index incRowY, Index incColY)
{
    for (Index i=0; i<m; ++i) {
        for (Index j=0; j<n; ++j) {
            Y[i*incRowY+j*incColY] += alpha*X[i*incRowX+j*incColX];
        }
    }
}

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

template <typename T, typename Index>
void
gescal(Index m, Index n,
       T alpha,
       T *X, Index incRowX, Index incColX)
{
    if (alpha!=T(1)) {
        for (Index i=0; i<m; ++i) {
            for (Index j=0; j<n; ++j) {
                X[i*incRowX+j*incColX] *= alpha;
            }
        }
    }
}

} // namespace ulmBLAS

#endif // HPC_ULMBLAS_h

#ifndef HPC_GEMM_REFCOLMAJOR_H
#define HPC_GEMM_REFCOLMAJOR_H 1

#include "ulmblas.h"

namespace refColMajor {

template <typename T, typename Index>
void
gemm(Index m, Index n, Index k,
     T alpha,
     const T *A, Index incRowA, Index incColA,
     const T *B, Index incRowB, Index incColB,
     T beta,
     T *C, Index incRowC, Index incColC)
{
    ulmBLAS::gescal(m, n, beta, C, incRowC, incColC);
    for (Index j=0; j<n; ++j) {
        for (Index l=0; l<k; ++l) {
            for (Index i=0; i<m; ++i) {
                C[i*incRowC+j*incColC] += alpha*A[i*incRowA+l*incColA]
                                               *B[l*incRowB+j*incColB];
            }
        }
    }
}

} // namespace refColMajor

#endif // HPC_GEMM_REFCOLMAJOR_H