使用scipy.integrate.odeint求解微分方程时遇TypeError问题求助

我是Python新手，尝试使用scipy.integrate.odeint求解微分方程，但始终遇到TypeError: 'float' object is not callable错误，无法让odeint正常工作。

我的代码如下：

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
from scipy.interpolate import CubicSpline
from scipy.integrate import odeint
from math import *

# Define parameters
alpha = 52.875
beta = 13.345
gamma = -1.44
delta = 2.29

# Define model
def model(h,t,om):
    halflife = alpha - (beta(-delta+gamma*om))
    k = log(2)/halflife
    dherb_dt = -kh
    return dherb_dt

# Initial condition
h0 = 4.271 # mg/kg, assuming a 2.67 pt/acre application of Dual II Magnum

# Time, in days, to interpolate over
t = np.linspace(0, 20)

# Solve ODE
om = 2.5
y1 = odeint(model, h0, t, args=(om,))

# Plot
plt.plot(t,y1)
plt.xlabel("Months")
plt.ylabel("Dose")
plt.show()

错误信息：

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Input In [17], in <cell line: 22>()
     20 # Solve ODE
     21 om = 2.5
---> 22 y1 = odeint(model, h0, t, args=(om,))
     24 # Plot
     25 plt.plot(t,y1)

File ~\anaconda3\envs\agron893\lib\site-packages\scipy\integrate\_odepack_py.py:241, in odeint(func, y0, t, args, Dfun, col_deriv, full_output, ml, mu, rtol, atol, tcrit, h0, hmax, hmin, ixpr, mxstep, mxhnil, mxordn, mxords, printmessg, tfirst)
    239 t = copy(t)
    240 y0 = copy(y0)
---> 241 output = _odepack.odeint(func, y0, t, args, Dfun, col_deriv, ml, mu,
    242                          full_output, rtol, atol, tcrit, h0, hmax, hmin,
    243                          ixpr, mxstep, mxhnil, mxordn, mxords,
    244                          int(bool(tfirst)))
    245 if output[-1] < 0:
    246     warning_msg = _msgs[output[-1]] + " Run with full_output = 1 to get quantitative information."

Input In [17], in model(h, t, om)
      8 def model(h,t,om):
----> 9     halflife = alpha - (beta(-delta+gamma*om))
     10     k = log(2)/halflife
     11     dherb_dt = -kh

TypeError: 'float' object is not callable

修复方案 #

错误核心是Python中乘法不能省略运算符，你在两处代码里遗漏了*号：

• beta(-delta+gamma*om)：beta是float变量，被误当作函数调用，正确写法为beta * (-delta + gamma*om)
• -kh：k和h之间缺少乘法运算符，正确写法为-k * h

修改后的完整代码：

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
from scipy.interpolate import CubicSpline
from scipy.integrate import odeint
from math import *

# Define parameters
alpha = 52.875
beta = 13.345
gamma = -1.44
delta = 2.29

# Define model
def model(h,t,om):
    halflife = alpha - (beta * (-delta + gamma*om))  # 修复乘法运算符
    k = log(2)/halflife
    dherb_dt = -k * h  # 修复乘法运算符
    return dherb_dt

# Initial condition
h0 = 4.271 # mg/kg, assuming a 2.67 pt/acre application of Dual II Magnum

# Time, in days, to interpolate over
t = np.linspace(0, 20)

# Solve ODE
om = 2.5
y1 = odeint(model, h0, t, args=(om,))

# Plot
plt.plot(t,y1)
plt.xlabel("Days")  # 建议改为Days，与t的单位一致
plt.ylabel("Dose")
plt.show()

内容的提问来源于stack exchange，提问作者s_o_c_account