.. _muon_model_fitting_tab-ref: Model Fitting Tab ----------------- .. image:: ../../images/muon_interface_tab_model_fitting.png :align: right :height: 400px Overview ^^^^^^^^ The model fitting tab is used to perform a fit across fit parameters and sample logs found in a results table within the :ref:`Muon Analysis ` and :ref:`Frequency Domain Analysis `. To use Model fitting it must first be enabled via the :ref:`feature flags `. This tab allows you to select a results table, before selecting the data that should be plotted on the x and y axes. It is then possible to perform a fit using a selected fit function. The selected model fit data is displayed in a plotting pane on the right hand side of the interface. An example model fit plot is seen in the image below. .. image:: ../../images/muon_interface_tab_model_fitting_plot.png :align: right :height: 400px **Fit** Executes the specified fit. **Undo Fit** Undoes the previously performed fit. **Results table** Allows you to select a results table from a drop-down menu. **Select data** Allows you to select the fit parameter or sample log data to be plotted on the x and y axis. **Covariance Matrix** Opens the normalised covariance matrix for the currently selected fit domain. Fit function browser ^^^^^^^^^^^^^^^^^^^^ .. image:: ../../images/muon_interface_tab_fitting_browser.png :height: 125px Right clicking in the central box will bring up a context menu for adding or removing functions. **Property** This is a list of property names, individual functions can be collapsed down for greater legibility. **Value** This lists the initial guesses for variables within fitting functions. Variables can be fixed for a given fit from the edit parameter values dialog box (click the ellipsis to the right of the value box). Fit properties browser ^^^^^^^^^^^^^^^^^^^^^^ **Start/End X** Defines the boundary values for the fit calculation. **Minimizer** Choose the minimisation method for the fit. Used By ^^^^^^^ :ref:`Muon Analysis ` :ref:`Frequency Domain Analysis `