将参数传递给fsolve

Question

我正在解决一个有很多常数的非线性方程.
我创建了一个解决方案,如:

def terminalV(Vt, data):
    from numpy import sqrt
    ro_p, ro, D_p, mi, g = (i for i in data)
    y = sqrt((4*g*(ro_p - ro)*D_p)/(3*C_d(Re(data, Vt))*ro)) - Vt
    return y

然后我想做:

data = (1800, 994.6, 0.208e-3, 8.931e-4, 9.80665)
Vt0 = 1
Vt = fsolve(terminalV, Vt0, args=data)

但是fsolve解压缩data并传递太多参数才能terminalV运行,所以我得到:

TypeError:terminalV()只需2个参数(给定6个)

所以,我的问题可以以某种方式将一个元组传递给被调用的函数fsolve()？

Answer 1

问题是你需要使用星号来告诉你的函数重新打包元组.将参数作为元组传递的标准方法如下:

from numpy import sqrt   # leave this outside the function
from scipy.optimize import fsolve

#  here it is     V
def terminalV(Vt, *data):
    ro_p, ro, D_p, mi, g = data   # automatic unpacking, no need for the 'i for i'
    return sqrt((4*g*(ro_p - ro)*D_p)/(3*C_d(Re(data, Vt))*ro)) - Vt

data = (1800, 994.6, 0.208e-3, 8.931e-4, 9.80665)
Vt0 = 1
Vt = fsolve(terminalV, Vt0, args=data)

没有fsolve,也就是说,如果你只是想自己调用terminalV,例如,如果你想看到它的值Vt0,那么你必须data用星号解包:

data = (1800, 994.6, 0.208e-3, 8.931e-4, 9.80665)
Vt0 = 1
terminalV(Vt0, *data)

或单独传递值:

terminalV(Vt0, 1800, 994.6, 0.208e-3, 8.931e-4, 9.80665)