小编Pas*_*ion的帖子

我是一个蟒蛇新手.我正在尝试使用python评估普朗克方程.我写了一个简单的程序.但是,当我给它输入时,给我一个错误.任何人都可以告诉我哪里出错了？这是程序和错误:

程序:

from __future__ import division
from sympy.physics.units import *
from math import *
import numpy
from scipy.interpolate import interp1d

#Planck's Law evaluation at a single wavelength and temperature
def planck_law(wavelength,temperature):
    T=temperature
    f=c/wavelength
    h=planck
    k=boltzmann
    U=2*h/(c**3)*(f**3)/(exp(h*f/(k*T))-1)
    return U.evalf()

输入:我已将函数导入为'cp',输入如下

value = (cp.planck_law(400,2000))

错误:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>`enter code here`
  File "Camera_performance.py", line 14, in planck_law
  U=2*h/(c**3)*(f**3)/(exp(h*f/(k*T))-1)
  File "/usr/lib/python2.7/dist-packages/sympy/core/expr.py", line 221, in __float__
  raise TypeError("can't convert expression to float")

TypeError: can't convert expression to …