| T O P I C R E V I E W |
| regal |
Posted - 10/16/2007 : 6:01:19 PM
I am currently evaluating Origin 8 and I have a few questions:
1) In the built-in nonlinear fitting functions are the partial derivatives analytically defined? If so how do I find these equations?
2) How do I define partial derivatives in the user-defined fitting functions interface?
3) When using the curve fitting tools the program keeps putting little purple tabs on the graph. Can you point me to the section of the manual that will tell what these are and how I can get rid of them?
4) How do I get Origin 8 to stop putting the fitting results in different tabs within my "book"? I just want it to leave my dataset in the book as is so I don't have to keep toggling back to it.
Thank you,
Cindy
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| 4 L A T E S T R E P L I E S (Newest First) |
| larry_lan |
Posted - 10/22/2007 : 02:31:16 AM
Hi Cindy:
1). This is by design. If your fit was converged, No more iterations occur if you click the Fit button, but it will still need some time to create result worksheets. However, if your fit did not converged after you clicking Fit till converged button, Origin 8 will try to make it converged by some more iterations.
Right now, as a work around, you can just press the Fit button directly if you only need a specific number of iterations. If you want to see the result before clicking Fit button, and your model is overparameterized, maybe you can click the Fit till converge button and then press the Initialized Parameters button, then press Fit. We are considering adding a Done button like 7.5, but still need more discussion.
2a). What you can do is creating an empty hidden workbook before bringing up the NLFit dialog, and specify the output destination to this <existing> book.
2b). To remove data column headings on the pasted table, you can create a table theme. Paste the following lines on a text editor (such as Windows Notepad)
[DataLinks]
Entry1=Notes![Equation]
Entry2=RegStats![AdjRsq]
Entry3=Parameters!(Value,Error)
And then save as an .INI file, such as NewTable.INI in the \CustomTable folder of Orign .exe folder. Specify this file on the following edit box:
We haven't documented how to created such theme since it looks like a very Advanced option, and user should modify the .ini files. Anyway, I will add this context on our wiki page. Before finished, you can refer to the other .ini files on \CustomTable folder. (Note, the lines starts by ";" are commented)
2c). Sorry, this is a bug, we will fix it in SR1.
3). You can press Shift key and select the theme to open NLFit dialog.
Maybe this tutorial can help.
Thanks
Larry
OriginLab Technical Services
Edited by - larry_lan on 10/22/2007 04:08:05 AM |
| regal |
Posted - 10/21/2007 : 10:40:39 PM
Thanks for the information. I have been using Origin 8 some now, and I have some more detailed questions essentially how I make Origin 8 do what I am used to in Origin 7:
1) In the NLSF dialog I would like the equivalent of the "done" button in the Origin 7 fitting dialog. I want to be able to iterate just a specific number of times and then have Origin go back to the graph and display the results. In Origin 8 it seems the only way I can do this is press the "fit" button, but then additional iterations occur (taking time I don't want to wait) before the results are displayed.
2) I also am still working on getting the reporting of fit results to do what I want. In general I am trying to get less information reported to reduce the clutter every time I fit. Below are some things I still can't seem to find in Settings->Advanced->Output Results->Output Report Tables To:
- I want to have the reported results reported to a "hidden" book.
- In the results table pasted to the graph I don't want it to list the data column heading. (It currently lists the data column label in every row of the first column of the table.)
- Under the following conditions the residuals output settings do not seem to be saved properly to my dialog theme (the residuals setting reverts to the factory default the next time I open the dialog):
Output Report Tables To - Book - none
Output Fitted Values To - <new>
Output Residuals to - <fittedvalue>
3) I would like to be able to open the nonlinear curve fitting dialog to my custom dialog theme instead of the factory settings. I don't want to fit to the exact same fit as my previous fit as is done when I click on my dialog theme as it appears in the analysis pull down menu. I want to open the full dialog to my theme without having to toggle from the factory settings every time. |
| larry_lan |
Posted - 10/16/2007 : 10:17:15 PM
Hi Cindy:
For question 2):
Sorry we miss the partial derivatives part in our manual. You can define the partial derivatives in Function Organizer. To know more about how to define a user-defined function in Function Organizer, please refer to:
Regression and Curve Fitting > Nonlinear Curve Fitting > Fitting Functions and the Fitting Function Organizer
of Origin Help. Or read the online help here
Now I will show you how to define partial derivatives using the equation:
y = a + b*x;
a). Press F9 to open Function Organizer. New a Category and new a Function. Name the function such as MyLine.
b). Make sure to check the Derivatives checkbox and define the function as follow:
Noticed that in the Function edit box, the function body is:
y = a + b*x;
dy_a = 1;
dy_b = x;
where dy_a = 1 and dy_b = x specifies the partial derivatives for parameters. You can also click the  button to check and compile the function.
c). Save the function and close FO. Then you can use this function in the NLFit dialog. Partial Derivative will speed up the fitting procedure, however, it's not necessary.
For question 1):
The built-in functions have compile as a dll file so you can't see the function body. However, you can define an External DLL fitting function which work as fast as the built-in functions. And you can also define the partial derivatives when creating External DLL fitting functions. To know more about it, please drag & drop the file FittingWithExternalDLL.opx on the \Samples\Curve Fitting folder of your Origin .exe folder to Origin workspace. Then there will be a new folder named Fitting with External DLL in your Origin User Folder. Please read the PDF help for more information.
Thanks
Larry
OriginLab Technical Services
Edited by - larry_lan on 10/16/2007 10:47:53 PM |
| cpyang |
Posted - 10/16/2007 : 7:45:36 PM
1) 2) Maybe someone else can help answer these two questions better.
3) These are Analysis Markers. You can hide them by Data->Analysis Markers->Hide, or just Cntrl-Shift-M to toggle them.
You can double-click on these markers to open the Change Parameter dialog, in this case this will open the NLFit dialog again to allow you to make changes to redo the fitting.
You can read this or this one.
4) You can control the output location of analysis results from the Fitting dialog by
Settings->Advanced->Output Results->Output Report Tables To
and select <New>. Once you have changed any of these settings, it is remembered into the <last used> theme file or the settings can be saved into a new theme file. You can read more here
CP
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