Multiply

#define MYMULTIPLYRES(a,b) (0.0f+a*b*M)
#define MYMULTIPLYLOOP(a,b, C)      \
for (int i = 0; i < (N); ++i)               \
{                                                   \
for (int j = 0; j < (N); ++j)               \
        {                                           \
        C[i][j] = MYMULTIPLYRES((a), (b));   \
        }                                           \
}                                                   \