Fitting functions

Among others HistPresent's canvas provides a popup menu Fit/Calibrate (see fig. 3). Several predefined functions like Polynomials and Gauss+High Tail are available. In this case marks which are activated with the middle mouse button are used to define limits and approximate means for a fit. Start parameters are estimated and editable by the user.

A second more general way is to use a ROOT macro. Commands Edit User Fit Macro and Execute User Fit Macro are provided for this. If with Edit User Fit Macro a non existing file name is given the user can choose from a few examples as templates. Again this is to put the entrance threshold to use ROOT as low as possible.

Figure 4: Widgets used with Fitting

For 2-dim histograms hooks are provided to fit slices and 2d functions. Also here examples are provided to start with.

Fig. 5 shows the 2-dim histogram from the builtin tutorial and the result of the example fit macro.

Figure 5: Example of 2d fit