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PatrickP
United Kingdom
4 Posts |
 Posted - 10/28/2016 : 6:34:38 PM
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So I am having difficulties getting origin to calculate which model is the best.
I have a set of 10 x and y values corresponding a gaussian like peak. I want to use them to find the best number of peaks that could describe my data. It looks like origin is unable to "compare models" for my fittings, and I can;t figure out how to do it manually. Any help please? |
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JacquelineHe
287 Posts |
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PatrickP
United Kingdom
4 Posts |
Posted - 11/01/2016 : 4:20:04 PM
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Hi JacquelineHe,
Sadly Origin will not let me compare them. I looked into it and they both were analysed the same way (out of the two provided) so it should not be a problem there. Still.
I think the problem is that the results I get after fitting the multiple Gaussians to my data are not compatible with the model comparison tool.
What I have is 10 data points representing a peak. A Gaussian like peak. By fitting one, two or three peaks I can get better and better fitting results to my data. I want to show that fitting 3 peaks to my data is over-fitting and fitting one is under-fitting. Thus 2 peaks gives me the best BIC value that supports my analysis AND also explains the underlying physics of the system.
I just can not figure out how to use Origin pro to do this comparison.
Sincerely,
PatrikasP
quote:
Originally posted by JacquelineHe
Hi PatrickP,
I am not sure whether you have fitted your dataset by different function (models).
If so, you can compare the results of two models fit to the same dataset, select Analysis : Fitting : Compare Models from the Origin menu.
Please refer to these help pages:
http://www.originlab.com/doc/Quick-Help/Compare-Datasets-FittingModels
http://www.originlab.com/doc/Origin-Help/PostFit-CompareFitFunc-Dialog
Please note: these pages are for the last version of Origin.
If this information is not helpful for you, could you please tell us more detail about your question?
Thanks
Jacqueline
OriginLab
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PatrickP
United Kingdom
4 Posts |
Posted - 11/05/2016 : 9:06:51 PM
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| bump |
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JacquelineHe
287 Posts |
Posted - 11/07/2016 : 10:26:40 PM
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Hi PatrickP,
1. You could fit your dataset with 1 peak, 2 peaks and 3 peaks in NLFit tool
respectively.
About how to fit Multiple Peaks with Replicas in the ”Nonlinear Curve Fit“ dialog, please refer to this page:
http://www.originlab.com/doc/Origin-Help/Fit-MultiPeak-Replica
Then you will get three results.
2. Use "Fitting Compare Models“ tool to compare these three cases.
Please note in this tool, you just can compare two result once, so you need to compare twice.
First: choose 1 peak and 2 peaks result
Second:choose 2 peaks and 3 peaks result
And choose “BIC” as “Comparison Method”.
Please refer to this help page:
http://www.originlab.com/doc/Origin-Help/PostFit-CompareFitFunc-Dialog
http://www.originlab.com/doc/Quick-Help/Compare-Datasets-FittingModels
If you still can not do that, could you mind to send your project file with your dataset to our Tech Support department <tech@originlab.com>?
With the file, please send us your detailed version and Serial Number information. You can check it by selecting "Help: About Origin" in the menu.
Thanks
Jacqueline
OriginLab
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Edited by - JacquelineHe on 11/07/2016 10:27:52 PM |
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PatrickP
United Kingdom
4 Posts |
Posted - 11/09/2016 : 5:20:37 PM
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Hi JacquelineHe,
Yup! That worked. Thank you so much!
Cheers!
Patrick
quote:
Originally posted by JacquelineHe
Hi PatrickP,
1. You could fit your dataset with 1 peak, 2 peaks and 3 peaks in NLFit tool
respectively.
About how to fit Multiple Peaks with Replicas in the ”Nonlinear Curve Fit“ dialog, please refer to this page:
http://www.originlab.com/doc/Origin-Help/Fit-MultiPeak-Replica
Then you will get three results.
2. Use "Fitting Compare Models“ tool to compare these three cases.
Please note in this tool, you just can compare two result once, so you need to compare twice.
First: choose 1 peak and 2 peaks result
Second:choose 2 peaks and 3 peaks result
And choose “BIC” as “Comparison Method”.
Please refer to this help page:
http://www.originlab.com/doc/Origin-Help/PostFit-CompareFitFunc-Dialog
http://www.originlab.com/doc/Quick-Help/Compare-Datasets-FittingModels
If you still can not do that, could you mind to send your project file with your dataset to our Tech Support department <tech@originlab.com>?
With the file, please send us your detailed version and Serial Number information. You can check it by selecting "Help: About Origin" in the menu.
Thanks
Jacqueline
OriginLab
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Bayesian Information Criterion For Gaussian...