FIT2D for 1-D ``Peak'' Fitting

Both 1-D and 2-D models may be fitted to experimental data using a variety of minimisation methods. 1-D model fitting is available within the MFIT (MULTIPLE 1-D FITTING) interface. The main menu is shown in Figure 12.

Figure 12: A Fitted 1-D Peak Model

Fit models may be defined using the INITIALISE sub-menu. A fit model may be constructed from an arbitrary number of peak functions (Gaussian, Lorentzian, and Voigt) and trigonometric or exponential decay functions, and a polynomial function of specified order. The SET-UP form allows the control parameters to be varied e.g. Weighted fitting or not (provided variance arrays exist). The CONSTRAINTS form allows individual model parameters to be constrained, or set to freely vary. The OPTIMISE button optimises the model to the data, according to the current control parameters.

The display of the fitted model and the data is shown in the upper X/Y graph in Figure 12, and beneath is a display of the residuals. This graphical display of the results may be saved as a PostScript file using the PRINT button (while this is displayed in the graphics window).