Tutorial:Fit Multiple Datasets by Fitting One and then Using Those Fit Parameters for Other Datasets

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Summary

In some cases, you might have multiple datasets, and want to fit them using the user-defined function without parameter initial code. For increased efficiency, you can fit one and then apply the fit parameters for other datasets.

Minimum Origin Version Required: Origin 8.6

What you will learn

  • How to perform an independent fit.
  • How to fit one of multiple datasets by doing 1-iteration, full-iteration.
  • How to apply the parameter values of one dataset to other datasets.

Example

  1. Create a user-defined function MyExp by following the steps in this tutorial.
  2. Import \Samples\Curve Fitting\Exponential Decay.dat to Origin worksheet.
  3. Highlight all columns and then select Analysis: Fitting: Non-linear Curve Fit from the menu to open the NLFit dialog.
  4. Select the function just defined in Settings tab, Function Selection page:
    Image:Fit_Multiple_Datasets_by_Fitting_One_Firstly.png
  5. Switch to Parameters tab, enter 80, 100, -5 on the Value column as initial values for y0, a, b of the first dataset. Then select 1 from the independent fit drop-down list and iterate the first dataset until converged.
    Image:Fit_Multiple_Datasets_by_Fitting_One_Firstly_01.png
  6. The parameter values are calculated and the fitting result is hinted in the left corner of this dialog.
    Image:Fit_Multiple_Datasets_by_Fitting_One_Firstly_02.png
  7. To initialize the parameters of other datasets, apply the parameter values of the first dataset to other datasets by right-clicking the values, and then selecting Apply Whole Set of "Value" to All Datasets from the fly-out menu.
    Image:Fit_Multiple_Datasets_by_Fitting_One_Firstly_03.png
  8. Click Fit button to finish the fitting for all datasets.
    Image:Fit_Multiple_Datasets_by_Fitting_One_Firstly_04.png
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