如何修复 scipy 的 odeint 函数中的 np.float64 not callable 错误？

Question

所以我试图用 scipy odeint 函数求解一组耦合的 ODE-s，并且错误：'numpy.float64' object is not callable 不断弹出。我已经对这个功能有了一些经验，但我无法弄清楚哪一部分是错误的。这是我的代码：

import numpy as np
import matplotlib.pyplot as plt
from scipy.integrate import odeint


def ODE(f, t):
    """Function containing the ODE-s, to be used in odeint"""
    x, vx, y, vy = f
    ax = -2.0*y**2*x(1 - x**2)*np.exp(-(x**2 + y**2))
    ay = -2.0*x**2*y(1 - y**2)*np.exp(-(x**2 + y**2))
    return np.array([vx, ax, vy, ay])
    

def trajectory(impactpar, speed):
    """Using odeint to calculate values"""
    x0 = impactpar
    vy = speed
    y0 = -2
    vx = 0
    initvals = [x0, vx, y0, vy]
    maxtime = 10 / speed
    time = np.linspace(0, maxtime, 300)
    result = odeint(ODE, initvals, time)
    return result


"""setting initial conditions for trajectory()"""
a_x0 = np.random.randint(-9000, 9001, 1)[0]/1e4
a_vy = np.random.randint(1, 5000, 1)[0]/1e4
xt = trajectory(a_x0, a_vy)[0]
yt = trajectory(a_x0, a_vy)[2]

这是我收到的完整错误消息：

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-55-40f25e7b2ba0> in <module>
     28 a_x0 = np.random.randint(-9000, 9001, 1)[0]/1e4
     29 a_vy = np.random.randint(1, 5000, 1)[0]/1e4
---> 30 xt = trajectory(a_x0, a_vy)[0]
     31 yt = trajectory(a_x0, a_vy)[2]

<ipython-input-55-40f25e7b2ba0> in trajectory(impactpar, speed)
     22     maxtime = 10 / speed
     23     time = np.linspace(0, maxtime, 300)
---> 24     result = odeint(ODE, initvals, time)
     25     return result
     26 

E:\Coding\Anaconda\lib\site-packages\scipy\integrate\odepack.py 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)
    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."

<ipython-input-55-40f25e7b2ba0> in ODE(f, t)
      9     """Function containing the ODE-s, to be used in odeint"""
     10     x, vx, y, vy = f
---> 11     ax = -2.0*y**2*x(1 - x**2)*np.exp(-(x**2 + y**2))
     12     ay = -2.0*x**2*y(1 - y**2)*np.exp(-(x**2 + y**2))
     13     return np.array([vx, ax, vy, ay])

TypeError: 'numpy.float64' object is not callable

如果有人能帮助我，我将不胜感激

Answer 1

正如它所说的那样，浮点变量不是函数，因此不能被调用。您需要将 x(...) 替换为 x*(...)。

如何修复 scipy 的 odeint 函数中的 np.float64 not callable 错误？

How do I fix np.float64 not callable error in scipy's odeint function?

python

numpy

scipy

ode

odeint