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asked 2012-09-20 23:26:30 -0500

mattias gravatar image


I'm trying to use scipy.optimize.root without any luck ( An import attempt returns: "'module' object has no attribute 'root'"

Any suggestions on how I can get this module?

Thanks, jv

Methods tried:

"import scipy from scipy import optimize from scipy.optimize import root"

"import scipy from scipy import optimize sol = optimize.root(q, [0., 0.])"

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`root` was only introduced in 0.11.0; `import scipy; print scipy.__version__` gives 0.9.0 in Sage 5.3. I don't think you're doing anything wrong, it's just that Sage's `scipy` is out of date with respect to that doc.

DSM gravatar imageDSM ( 2012-09-21 03:47:21 -0500 )edit

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answered 2012-09-21 01:12:33 -0500

achrzesz gravatar image

updated 2012-09-21 08:01:50 -0500

Perhaps you should try fsolve:

import numpy as np
import scipy
from scipy import optimize as opt
y_a =50.;y_b =50.; x0 = 40. 
v=lambda n:np.sqrt(n)
v1=lambda n:1/(2*np.sqrt(n))
u=lambda n:np.sqrt(n)
u1=lambda n:1/(2*np.sqrt(n))
alpha_a = .2 ;alpha_b = .2
def f(x):
   f1 =((1-alpha_b)*v1(g_a+alpha_b*(x0 - g_a)))/((1-alpha_a)*v1(x0-g_a+alpha_a*(g_a)))-((v(g_a+alpha_b*(x0-g_a))-u(y_a)+u(y_a-x_a))/(v(x0-g_a+alpha_a*(g_a))-u(y_b)+u(y_b-(x0-x_a))))
   f2 =(u1(x_a)/u1(x0-x_a))-((v(g_a+alpha_b*(x0-g_a))-u(y_a)+u(y_a-x_a))/(v(x0-g_a+alpha_a*(g_a))-u(y_b)+u(y_b-(x0-x_a))))
   return [f1,f2]
# if you copy to the console then first copy and evaluate the above 
# and next copy and evaluate the remaining part (problems with edit?)
print s
print f([20,20])
#[ 20.  20.]
#[0.0, 0.0]
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Asked: 2012-09-20 23:26:30 -0500

Seen: 460 times

Last updated: Sep 21 '12