3.38 FAQ-267 How do I speed up the fitting routine for the user-defined function with integration?

Last Update: 2/4/2015

If your Origin C, integration by using NAG library, user-defined fitting function is not fast enough, you can call GSL library to perform integration fitting.

Please refer to this tutorial for how to define the Origin C fitting function.

Please refer to using external DLL for how to create an external DLL fitting function.


There is an opx package, FittingWithExternalDLL.opx, in the folder of <Origin Installation Directory>/Samples/Curve Fitting/.

  1. Drag and drop it onto Origin to install it.
  2. A folder, Fitting with External DLL, is added to your User Files Folder, including the sample codes, help documentation, etc..
  3. The third example fitting function, which is commented out, in FitFuncs.c, will guide you to call the GSL lib to perform integration fitting using external DLL.



Keywords:speed, integration, dll, GSL, fit