docs: public static void scale( double alpha , DMatrixD1 a )
      {
          // on very small matrices (2 by 2) the call to getNumElements() can slow it down
          // slightly compared to other libraries since it involves an extra multiplication.
          final int size = a.getNumElements();
  
          for( int i = 0; i < size; i++ ) {
              a.data[i] *= alpha;
          }
      }