[SciPy-user] lsq problem

Gael Varoquaux gael.varoquaux@normalesup....
Thu Feb 15 00:54:59 CST 2007


Hi Tommy,

Maybe the cookook example at http://scipy.org/Cookbook/FittingData can
help you.

Gaël

On Wed, Feb 14, 2007 at 09:16:50PM -0500, Tommy Grav wrote:
> I need to fit a gaussian profile to a set of points and would like to  
> use scipy (or numpy) to
> do the least square fitting if possible. I am however unsure if the  
> proper routines are
> available, so I thought I would ask to get some hints to get going in  
> the right direction.

> The input are two 1-dimensional arrays x and flux, together with a  
> function

> def Gaussian(a,b,c,x1):
> 	return a*exp(-(pow(x1,2)/pow(c,2))) - c

> I would like to find the values of (a,b,c), such that the difference  
> between the gaussian
> and fluxes are minimalized. Would scipy.linalg.lstsq be the right  
> function to use, or is this
> problem not linear? (I know I could find out this particular problem  
> with a little research, but
> I am under a little time pressure and I can not for the life of me  
> remember my old math
> classes). If the problem is not linear, is there another function  
> that can be used or do I have
> to code up my own lstsq function to solve the problem?

> Thanks in advance for any hints to the answers.

> Cheers
>    Tommy
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> SciPy-user@scipy.org
> http://projects.scipy.org/mailman/listinfo/scipy-user

-- 
  Gael Varoquaux,
  Groupe d'optique atomique,
  Laboratoire Charles Fabry de l'Institut d'Optique
  Campus Polytechnique, RD 128
  91127 Palaiseau cedex FRANCE
  !!!! NEW Phone number !!!!
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