Re: exponential fitting

[Gert Van den Eynde]

On Wed, 4 Sep 2002 16:41:39 +0200
address@hidden wrote:

> Fine. It's working now, thanks a lot.
> 
> expfit is nice, really. the only two problems are:
> 1.) the data is shifted very often, that's why I need the 'c' 
> {y=a*exp(b*x)+c}. 

expfit will return a term where b = 0 and a is the constant 'c' you're looking 
for (exp(0*x) = 1).

> 2.) expfit doesn't calculate the R^2 for me.
> maybe I get rid of these, but if you have already a solution - just tell me.

expfit returns the root mean square (rms): 
sqrt(sum((data(i)-fitting_evaluation(i))**2)), you would want to square this, 
no ?


Hope this helps,


Gert Van den Eynde

SCK-CEN
Reactor Physics & MYRRHA Dept
Mol,Belgium



-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------