| T O P I C R E V I E W |
| altomare |
Posted - 06/20/2001 : 3:11:08 PM
Hi all,
I have a question about a fit and I hope someone can help me.
I have to fit some experimental data to the derivative of the log of a gamma function.
gammaln(x)=ln(gamma(x)) is already defined, but how can I have a fit to its derivative?
Thanks a lot
Fabio
PS I'm using origin 6.0 (not the professional edition)
Edited by - altomare on 06/20/2001 15:25:49 |
| 2 L A T E S T R E P L I E S (Newest First) |
| altomare |
Posted - 06/28/2001 : 5:51:32 PM
HI Greg,
thanks a lot for your answer: since there was nothing in the help I kind of suspected it.
I'm just wondering however if I can create an external function with Origin Professional (I may have access to an older version) and use it somehow. I have no idea if I can, I'm just contemplating the hipotesys. Would it be possible?
Thanks
Fabio |
| greg |
Posted - 06/25/2001 : 11:18:55 AM
There is an example of using LabTalk's Integrate command within a fitting function:
http://www.originlab.com/www/support/resultstech.asp?ItemID=121
Fitting with Integrals
, but I don't think that will help much. Origin does not do abtract math so a differentiation in this case would only be of discrete values - complicated by the fact that the derivative command (our discrete differentiation) will alter the dataset on which it operates (so you need a copy) and needs to be associated with the same X dataset as the original data.
Maybe consulting a calculus book will give you the functional form of what you seek which you can implement as a new function in Origin.
Edited by - greg on 06/25/2001 11:23:04 |
