code: @Nonnull
    @ReturnsMutableCopy
    public Matrix getR ()
    {
      final Matrix aNewMatrix = new Matrix (m_nCols, m_nCols);
      final double [] [] aNewArray = aNewMatrix.internalGetArray ();
      for (int nRow = 0; nRow < m_nCols; nRow++)
      {
        final double [] aDstRow = aNewArray[nRow];
        for (int j = 0; j < m_nCols; j++)
        {
          if (nRow < j)
            aDstRow[j] = m_aQR[nRow][j];
          else
            if (nRow == j)
              aDstRow[j] = m_aRdiag[nRow];
            else
              aDstRow[j] = 0.0;
        }
      }
      return aNewMatrix;
    }
docs: Return the upper triangular factor
  
  @return R