OverflowError: Python中的数学范围错误

Question

我是Python的新手，我遇到了这个问题:

import cmath as cm
import numpy as np
from scipy import special
from scipy.misc import derivative
def T(X, Y):
s0 = np.sign(X)
s1 = np.sign(X - 15)
s3 = np.sign(X + 15)
k0 = cm.sqrt( X**2 -(10*Y)**2 )/10
k1 = cm.sqrt( ((X - 15)**2) - (10*Y)**2 )/10
k3 = cm.sqrt( ((X + 15)**2) - (10*Y)**2 )/10
def z(k):
return complex(k, -Y)/cm.sqrt(k**2 + Y**2)
def w(k, s, x):
return np.array([[cm.exp(complex(0, 1)*k*x), cm.exp(-complex(0, 1)*k*x)], [s*z(k)*cm.exp(complex(0, 1)*k*x), -s*cm.exp(-complex(0, 1)*z(k)*x)/z(k)]])
I15 = np.linalg.inv(w(k1, s1, 5))
I05 = np.linalg.inv(w(k0, s0, 5))
I310 = np.linalg.inv(w(k3, s3, 10))
Omega = w(k1, s1, 0).dot(I15).dot(w(k0, s0, 5)).dot(I05).dot(w(k3, s3, 5)).dot(I310)
Omegan = special.eval_chebyu(19, np.trace(Omega)/2)*Omega - special.eval_chebyu(18, np.trace(Omega)/2)*np.identity(2)
I00 = np.linalg.inv(w(k0, s0, 0))
tt = I00.dot(Omegan).dot(w(k0, s0, 200))
t = 1/tt[0][0]
return cm.log(t)
def V(X):
Y0 = X*np.sin(np.deg2rad(2))/10
result = derivative(func=T, x0=Y0, args=(X,))*X/(20*np.pi)
return -result.imag
V = np.vectorize(V)
X = np.linspace(0.01, 10, 1000)
VX = V(X)

我得到一个OverflowError: math range error，当尝试运行此代码时。有没有办法避免这个错误?任何帮助都是感激的。谢谢!

Answer 1

如何调试:

1. 像这样更改函数w:

def w(k, s, x):
try:
return np.array([[cm.exp(complex(0, 1)*k*x), cm.exp(-complex(0, 1)*k*x)], [s*z(k)*cm.exp(complex(0, 1)*k*x), -s*cm.exp(-complex(0, 1)*z(k)*x)/z(k)]])
except OverflowError:
import pdb
pdb.set_trace()

2. 运行程序:

#> python myprog.py
--Return--
> /Users/xxx/tmp/myprog.py(19)w()->None
-> pdb.set_trace()
(Pdb)

3. 通过测试所有表达式来调试:

(Pdb) locals()
{'k': 3.5499997838094535j, 's': 1.0, 'x': 200, 'z': <function T.<locals>.z at 0x124770c10>, '__return__': None}
(Pdb) cm.exp(complex(0, 1)*k*x)
(4.47647977601281e-309+0j)
(Pdb) cm.exp(-complex(0, 1)*k*x)  # The problem is here x=200, x=199 works
*** OverflowError: math range error