3.9.2 Fitting

NLFit is Origin's non-linear fitting tool, first introduced in Origin version 8.0, and it can be controlled using Origin C. Navigate the categories below to see full Origin C examples using the non-linear fitter.

NLFit represents a complete rewrite from the older NLSF module, and it is what you see from the Origin GUI menu since version 8.0. NLFit handles the fitting process with a copy of the data during the iteration, so it is faster than NLSF, which directly accessed the worksheet during the minimization process, since it eliminates the overhead of external access to worksheet data.

Origin C class that wraps the low level API from the Origin 8 fitting engine. This class has no knowledge of Origin and works with copies of data in buffers. In order to use this class, you will be responsible of preparing all those buffers (pointers). This separation prepares for the future implementation of doing the fitting as a background process.
Higher level Origin C class that wraps the NLFit class with friendly interface to Origin objects. This class is the kernel in the Origin 8 NLFit Dialog. We recommend that you use this class in your Origin C code as the process to interface to Origin is rather complicated and NLFitSession class has taken care of all that complexity for you.
This section covers the following topics: