| T O P I C R E V I E W |
| pazmush |
Posted - 12/19/2008 : 10:21:52 PM
Can anyone give me a rough guide or tutorial on how to fit my own nonlinear function to some data? |
| 4 L A T E S T R E P L I E S (Newest First) |
| Deanna |
Posted - 12/30/2008 : 02:56:30 AM
Hi, you also send us an email. I have replied it. Please check.
Deanna
OriginLab Technical Services |
| pazmush |
Posted - 12/29/2008 : 11:38:55 AM
hi my emails havent been getting through so i thought i'd post here
sorry to bother you again but ive got this far now (see attachments).
As you can see my problem is that my data doesnt start from zero, how can i get around this problem with the curve fitting?
i used the formula;
y = ((h*exp(-a*x))/((3.14*b*(x+1/a))^0.5))*(exp((-(c-d*x)^2)/(b*(x+1/a))))
and parameters
h=5
a=10000
b=0.01
c-0.065 (fixed)
d=90
some of these parameter need a little fiddeling as c should equal 0.0025?
 |
| Shirley_GZ |
Posted - 12/22/2008 : 02:34:18 AM
Hi pazmush,
I'm not sure where the problem is, Would you please check your steps according to the below pages?
http://www.originlab.com/www/helponline/origin8/en/origin.htm#Regression_and_Curve_Fitting/User-Defined_Fitting_Functions.htm
http://www.originlab.com/www/helponline/origin8/en/origin.htm#Regression_and_Curve_Fitting/The_Fitting_Function_Organizer_dialog_box.htm
If still any problem, please send the FDF file, which can find through the FileName(.FDF) item in the Fitting Function Organizer dialog, and the data to tech@originlab.com, quote this post in the E-mail.
Thank you!
Shirley
Originlab Technical Service Team |
| pazmush |
Posted - 12/19/2008 : 11:38:09 PM
right, sorry, i think i understand the fitting process now, but when i perform an iteration origin seems to freeze up, what do you think might be wrong? |
