code: def cal_p(self, v, temp):
          
          if not isinstance(temp, np.ndarray):
              temp = np.asarray(temp)
          if not isinstance(v, np.ndarray):
              v = np.asarray(v)
          return self.cal_pst(v) + self.cal_pth(v, temp) + \
              self.cal_pel(v, temp) + self.cal_panh(v, temp)
docs: calculate total pressure at given volume and temperature
  
          :param v: unit-cell volume in A^3
          :param temp: temperature in K
          :return: pressure in GPa
          :note: 2017/05/10 temp must be numpy array.  If not, such as list,
              create an error.