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发帖数: 273 | 1 【 以下文字转载自 Quant 讨论区 】
发信人: myregmit (myregmit), 信区: Quant
标 题: solve integral eq. embeeded with another integral eq.
发信站: BBS 未名空间站 (Sun Mar 23 14:20:18 2014, 美东)
I need to solve an integral equation embedded with another integral equation
by python 3.2 in win7.
There are 2 integral equations.
The code is here:
import numpy as np
from scipy.optimize.minpack import fsolve
from numpy import exp
from scipy.integrate.quadpack import quad
import matplotlib.pyplot as plt
import sympy as syp
lb = 0
def integrand2(x, a):
print("integrand2 called")
return x**(a-1) * exp(-x)
def integrand1(x, b, c):
print("integrand1 called")
integral , err = quad(integrand2, lb/b, syp.oo , args=(1+c))
return c/(b*integral)
def intergralFunc1(b,c):
integral,err = quad(integrand1, 0, 10, args=(b,c))
print("integral is ", integral, " and err is ", err)
print("b is ", b, " and c is ", c)
return 10 - integral
def findGuess():
vfunc = np.vectorize(intergralFunc1)
f1 = np.linspace(0.01, 10,10)
f2 = np.linspace(0.01, 10,10)
result = vfunc(f1, f2)
plt.plot(f1, result)
plt.xlabel('f1')
plt.subplot(211)
plt.plot(f2, result)
plt.xlabel('f2')
plt.subplot(212)
plt.show()
def solveFunction():
sol= fsolve(intergralFunc1, 5, 5, full_output=True)
return sol
if __name__ == '__main__':
findGuess()
sol = solveFunction()
print("sol is ", sol)
print("verification: n")
print("f(b,c) is ", intergralFunc1(sol[0],5))
I got the results that make no sense.
integral is nan and err is nan
b is [ 5.] and c is 5
f(b,c) is nan
Any help would be appreciated !!! |
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