3.112 FAQ-654 How to fit multiple datasets?

Last Update: 7/27/2018

Do you have multiple datasets that you would like to fit simultaneously? With Origin, you can fit each dataset separately and output results in separate reports or in a consolidated report. Alternately, you can perform global fitting with shared parameters; or perform a concatenated fit which combines replicate data into a single dataset prior to fitting.

First you can click the triangle button next to Input Data to add multiple datasets to fitting dialog.

Multi-Data Fit Mode control is availble for switching between Concatenate/Independent fitting for multiple datasets. There are three options for the multiple datasets fit.

Independent-Consolidated Report
The input datasets are fitted separately. The reports are consolidated into one sheet.
Independent-Separate Report
The input datasets are fitted separately. The reports are output to different worksheets.
Concatenate
All input datasets are concatenated and fitted as one curve.
Global Fit (Available only in Nonlinear Curve Fit)
Simultaneous perform curve fitting on multiple datasets. Because datasets remain distinct, they may or may not "share" parameter values during the fit process. When a parameter is shared, a single parameter value is calculated for all datasets; When a parameter is not shared, a separate parameter value is calculated for each dataset.

A further alternative is to use Mathematics:Average Multiple Curves to produce a single new dependent dataset and fit this dataset. The result will be one set of parameters.

The table below discuss the different cases of fitting for multiple datasets

	Analysis: Fit Linear	Analysis: Fit Linear with X Error	Analysis: Polynomial Fit	Analysis: Nonlinear Curve Fit	Gadget: Quick Fit
Fit separately & at once	Multi-Data Fit Mode	Multi-Data Fit Mode	Multi-Data Fit Mode	Multi-Data Fit Mode	New Output for All Layers/Curves
Fit to Average of all datasets	Mathematics: Average Multiple Curves	Mathematics: Average Multiple Curves	Mathematics: Average Multiple Curves	Mathematics: Average Multiple Curves	Mathematics: Average Multiple Curves
One Fit to all datasets by combing all into a single dataset	Multi-Data Fit Mode(Concatenate)	Multi-Data Fit Mode(Concatenate)	Multi-Data Fit Mode(Concatenate)	Multi-Data Fit Mode(Concatenate)	NO
One Fit to all datasets with shared parameter	NO	NO	NO	Multi-Data Fit Mode(Global Fit)	NO

Keywords: multiple data, fitting, linear fit, nonlinear fit, linear fit with x error, polynomial fit, quick fit, concatenate fit, global fit, independent fit, consolidated report, average curve