15.3.2.4 Parameters Tab (Upper Panel)

NLFit Parameter tab.png

On this tab you can see and set parameter values and significant digits, and control whether parameter values should be varied or fixed during the iterative fitting process. This tab also displays error and other information for monitoring the fitting procedure.

Auto Parameter Initialization check box

Run automatic parameter initialization code for the chosen fitting function.

For all built-in functions, automatic parameter initialization codes are provided. For user-defined functions, this code is optional. If parameter initialization code is not supplied, all parameter values will register initially as missing values (even though Auto Parameter Initialization may be selected). In this case, you must enter estimated values before you can start fitting.

For more details, please see Parameter Initialization.

Hide button

Click this button to open the Hide dialog. Selected parameters are hidden in the parameter table. This may be useful while manipulating initial parameter values or formats. Hiding a parameter does not remove it from the fit process.

Hide parameter.png

Previous button and Next button

If you want to go back one iteration to check the parameters, you can click the Previous button Previous button.png, or likewise, you can click the Next button Next button.png to go forward one iteration.

Parameter Table

All parameters and properties are listed in tabular format.

Context menu brought up by right-clicking any column title

NLSF dialog Para tab 2.png

Right-click any column title and use the context menu to display (or hide) parameter properties. Select Show All Columns to display all columns.

These columns correspond to columns in the Peak Fit Parameter dialog. For details about each column, please see here.

Context menu brought up by right-clicking the tab title

Right-click the Parameter tab title to open a context menu:

NLSF dialog Para tab 1.png

This is the same menu that displays in the Peak Fit Parameter dialog. Please see Peak Fit Parameter Help for details.

Specify Value cell format

Value cells support Numeric, Date, and Time formats.

PTUP Para tab.png

Right-click the Value cell of a Param in the Parameters tab. Select Format Cells from the short-cut menu. In the Format Cells dialog, select a format from the Format drop-down list. For Date and Time formats, select from the Display drop-down list. To use a custom Date or Time format, select Custom Display from the Display drop-down list, and type the format in the Custom Display combo box.

PTUP Format Cells dlg.png

Formats of Lower Bounds and Upper Bounds cells in the Bounds tab can also be specified in the same way.

Copy/Paste Parameter Values

NLSF dialog Para tab 3.png

When doing an independent fit for multiple datasets with the same fitting function, you can use the fly-out menu to apply the current value to all similar parameters in other datasets.

For example, as in the above screenshot, right-click the value of parameter xc. Select Apply Same "Value" to All xc from the fly-out menu to apply 26 to the similar parameters, xc_1, xc_2, xc_3 and xc_4. Use this menu to copy and paste the initial values to all paralleled parameters.


Note:
  • During the fitting process, if a parameter is Fixed, the parameter value will not change until the check box is cleared.
  • The Share check box is available only when global fitting is used.
  • The parameter values and the Fixed check box status can be saved in a dialog Theme. For more information, see Fitting with Themes.
  • You can also specify these parameter settings when defining a fitting function. This can be done with the Parameter Settings box of the Function Organizer. For more information, see The Fitting Function Organizer dialog box.
  • Parameter settings in a dialog Theme are given priority over settings in the function definition file (FDF). When a theme is loaded, the initial parameter values stored with the theme will be used instead of the initial values in the function definition file.