const char *dgemm_desc = "Naive, three-loop dgemm.";
void square_dgemm( int n, double *A, double *B, double *C )
{
  for( int i = 0; i < n; i++ )
       for( int j = 0; j < n; j++ ) 
       {
            double cij = C[i+j*n];
            for( int k = 0; k < n; k++ )
                 cij += A[i+k*n] * B[k+j*n];
            C[i+j*n] = cij;
       }
  }