| T O P I C R E V I E W |
| dominik.mierzwa |
Posted - 03/29/2017 : 1:14:30 PM
Origin Ver. 2017 94E
Operating System: Windows 10 64bit
Hi,
I'd like to add user fitting function described with expression:
y=exp(-k*x^n)
where:
k and n are constants which should be calculated from the fitting
Starting conditions are as follows:
y0=1 - is moisture ratio from 1 to 0
x0=0 - is time from 0 to 21600 sec
Should k0 and n0 be also provided?
I have tried various combination with fitting function builder but unsuccessfully so far. How should I define such a function?
Kind regards,
Dominik |
| 2 L A T E S T R E P L I E S (Newest First) |
| Marboulin |
Posted - 04/03/2017 : 11:10:00 AM
Hi,
I was working before on Origin 7.0 and now we changed for 8.5. And in the 8.5 version the feature 'Fit Comparison' has disappeared... I was using that to compare the statistical differences between two Boltzmann fit (F-Test).
Can I still do Fit comparison in the 8.5 version? (don't want to compare dataset or models)
Thanks for your help!
|
| JacquelineHe |
Posted - 03/30/2017 : 02:06:53 AM
Hi Dominik,
1.You can create the User-defined function in the Fitting Function Builder
To know more detail, please refer to this tutorial:
http://www.originlab.com/doc/Tutorials/UserDef-FitFunc
2. If you want to define the X and Y range used when you fit the dataset, you can custom the range in "Data Selection" page under "Setting" tab of the NLFit dialog
http://www.originlab.com/doc/Origin-Help/NLFit-Dialog-SettingsTab#Data_Selection
3. If "k" and "n" are the paramters in your function, the k0 and n0 are their "Initial Value", right?
If so you can custom them when you create this function (Fitting Function Builder dialog:Function Body Page:Parameters Tab) http://www.originlab.com/doc/Origin-Help/FitFuncBuilder-FuncBody ,
or custom them when you do fitting (NLFit dialog:Parameters Tab) http://www.originlab.com/doc/Origin-Help/NLFit-Dialog-ParaTab
Thanks
Jacqueline
OriginLab |
|
|
