docs: def fmttime(tin):
      """Return LaTeX expression with time in scientific notation.
  
      Args:
          tin (float): the time.
      Returns:
          str: the LaTeX expression.
      """
      aaa, bbb = '{:.2e}'.format(tin).split('e')
      bbb = int(bbb)
      return r'$t={} \times 10^{{{}}}$'.format(aaa, bbb)