| Author |
 Topic  |
|
|
biglemon
China
Posts |
 Posted - 09/09/2004 : 03:02:03 AM
|
Origin Version (Select Help-->About Origin): 7.5
Operating System:Windwos 2000
Hi, everyone,
I'm a new Origin user, working on neuroscience.
As we know, compared with the built-in function, the user-defined curve fitting function must be well initiated in order to get the well fitted result. My question is, how to let the user-defined function work as well as the built-in functions.
Thank you!
|
|
|
easwar
USA
1965 Posts |
Posted - 09/09/2004 : 10:21:16 AM
|
Hello,
The parameter initialization for our built-in fitting functions is coded in Origin C. If you browse to any function in the advanced NLSF tool, such as say Gaussian in the Peak category, you can view the initialization code using the NLSF menu command Scripts->Parameter Initialization.
The initialization code uses many functions from the file internal.c, such as sort(), smooth(), yatxmin(), fwhm() etc. Note that in the initialization code, one can use the curve x_y_curve. This curve is a copy of the data that is being fit, and so can be manipulated at will to extract useful information for initializing the parameters of your function.
So you can try using these available functions, or write your own functions to assign initial values to parameters. The code will depend on what your function is, and what kind of analysis needs to be done on the fit data to determine good initial values.
If you need further help, you could contact tech support with your function code for suggestions on how to initialize your parameters.
Note that the initialization code does not have to be in Origin C. You can write LabTalk script code for initialization as well. With Origin C, the advantage is that many functions such as xatymin() are already available for your use.
Easwar
OriginLab
Edited by - easwar on 09/09/2004 10:22:31 AM |
 |
|
|
biglemon
China
Posts |
Posted - 09/09/2004 : 9:07:59 PM
|
Thank you very much!
quote:
Hello,
The parameter initialization for our built-in fitting functions is coded in Origin C. If you browse to any function in the advanced NLSF tool, such as say Gaussian in the Peak category, you can view the initialization code using the NLSF menu command Scripts->Parameter Initialization.
......
|
|
|
| |
Topic |
|
|
|
User-defined curve fitting