试着解方程中的B

2024-03-28 14:00:04 发布

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我在试着解那个长表达式中的变量B。它给了我一个错误,它不能转换成浮点数。我真的不知道这到底意味着什么,我需要做什么,以修复这一点,并获得一个B值。我是非常新的Python所以任何帮助将不胜感激。你知道吗

代码:

import matplotlib.pyplot as plt
import numpy as np
import math
from sympy.solvers import solve
from sympy import Symbol 

W = 1*(10**(-4)) 
mu = 300  
Cox = 6.906*(10**-6)
Leff = 1*(10**(-4))
Vg1 = 0.5
Vg2 = 1.0
Vg3 = 1.5
Vg4 = 2.0
Vth = 0.0259
tsi = 5 * (10 ** -7)
Vg = [0.5, 1, 1.5, 2]
Esi = 11.7
tox = 1.5 * (10 ** -7)
tsi = 5 * (10 ** -7)
ni = 1.5 * (10 ** 10)
q = 1.602 * (10 ** -19)

B = Symbol('B')

solve((Vg1/2*Vth) - math.log((2/tsi)*(np.sqrt((2*Esi*Vth)/(ni * q)))) - 
math.log(B) + math.log(np.cos(B)) - 2*11.7*(tox)/(3.9 * tsi), B)

错误:

TypeError                                 Traceback (most recent call last)
<ipython-input-3-003cda8dedbd> in <module>()
 18 B = Symbol('B')
 19 
 ---> 20 solve((Vg1/2*Vth) - math.log((2/tsi)*(math.sqrt((2*Esi*Vth)/(ni * 
  q)))) - math.log(B) + math.log(math.cos(B)) - 2*11.7*(tox)/(3.9 * tsi), B)

~\Anaconda3\lib\site-packages\sympy\core\expr.py in __float__(self)
237         if result.is_number and result.as_real_imag()[1]:
238             raise TypeError("can't convert complex to float")
 --> 239         raise TypeError("can't convert expression to float")
240 
241     def __complex__(self):

TypeError: can't convert expression to float

Tags: importlogtoxasnpmathfloatsymbol
1条回答
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1楼 · 发布于 2024-03-28 14:00:04

按照@jdehesa的建议,使用sympy表达式:

from sympy.solvers import nsolve
from sympy import Symbol, log, sqrt, cos

W = 1*(10**(-4)) 
mu = 300  
Cox = 6.906*(10**-6)
Leff = 1*(10**(-4))
Vg1 = 0.5
Vg2 = 1.0
Vg3 = 1.5
Vg4 = 2.0
Vth = 0.0259
tsi = 5 * (10 ** -7)
Vg = [0.5, 1, 1.5, 2]
Esi = 11.7
tox = 1.5 * (10 ** -7)
tsi = 5 * (10 ** -7)
ni = 1.5 * (10 ** 10)
q = 1.602 * (10 ** -19)

B = Symbol('B')

nsolve((Vg1/2*Vth) - sympy.log((2/tsi)*(sympy.sqrt((2*Esi*Vth)/(ni * q)))) - sympy.log(B) + sympy.log(sympy.cos(B)) - 2*11.7*(tox)/(3.9 * tsi), 1)

您试图求解的表达式是非线性的,因此您应该尝试用nsolve进行数值求解。你知道吗

注意:第二个参数是猜测结果应该接近什么。你知道吗

1我得到一个复杂的结果:

-17910.2176436326 - 37.1544916945789*I

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