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Jun-09-2020, 02:57 PM
(This post was last modified: Jun-12-2020, 10:56 PM by Gribouillis.)
Hi every one,
when i am trying solve this equation using fsolve with variables as list
![[Image: 2ZOfu.png]](https://i.stack.imgur.com/2ZOfu.png)
can any help me out.
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from optimize import fsolve
import numpy as np
T = np.array([137,145,150,152,159,160,184])
Di =np.array([1,0,1,1,1,0,1])
r = 5.0
def lnL(P):
mu, sigma = P
return -r*np.log(sigma)-(1/2)*np.sum(Di*((T-mu)/sigma)**2)+np.sum(1-Di)
sol = fsolve(lnL, (15.0,258.0))
sol
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i am getting this error
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fsolve: there is a mismatch between the input and output shape of the 'func' argument 'lnL'.Shape should be (2,) but it is (1,).
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Posts: 4,801
Threads: 77
Joined: Jan 2018
This is not an equation because there is no = sign. It is merely a scalar expression of the two variables mu and sigma. If you want to solve the equation "expression = 0", there will be a curve of solutions in the mu, sigma plane. If you look at the expression, you'll see that it is a quadratic equation in mu, which means that you could solve it explicitly and give mu as a function of sigma.
Posts: 2
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Joined: Jun 2020
Jun-10-2020, 03:32 PM
(This post was last modified: Jun-10-2020, 03:39 PM by djhak.)
(Jun-09-2020, 04:01 PM)Gribouillis Wrote: This is not an equation because there is no = sign. It is merely a scalar expression of the two variables mu and sigma. If you want to solve the equation "expression = 0", there will be a curve of solutions in the mu, sigma plane. If you look at the expression, you'll see that it is a quadratic equation in mu, which means that you could solve it explicitly and give mu as a function of sigma.
hi,
Actually it is equation only, while taking screen crop i missed that, here challenging is two variables are in list[],while passing them, i am getting error,
Posts: 4,801
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Jun-10-2020, 04:12 PM
(This post was last modified: Jun-10-2020, 04:13 PM by Gribouillis.)
djhack Wrote:here challenging is two variables are in list[],while passing them, i am getting error, This is not the problem. You are getting an error because you have a scalar function (1 real value) of two variables (2 real values). fsolve works when a function of n variables produces n values. This is the first line of the documentation, see the func argument.
Your problem doesn't have a unique solution.
I understand that you want to use an equation solver as a magic black box, but it can only solve the problems for which it was designed.
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