docs: public static void normalizeColumns(final double[][] m1) {
      final int columndimension = getColumnDimensionality(m1);
      for(int col = 0; col < columndimension; col++) {
        double norm = 0.0;
        for(int row = 0; row < m1.length; row++) {
          final double v = m1[row][col];
          norm += v * v;
        }
        if(norm > 0) {
          norm = FastMath.sqrt(norm);
          for(int row = 0; row < m1.length; row++) {
            m1[row][col] /= norm;
          }
        }
      }
    }