Parameters are special types of local variables that are recognized as model parameters in some platforms, such as Nonlinear fitting. They can be used in formulas just as ordinary local variables can.
To view examples of parameters
1. In the sample data folder that was installed when you installed JMP, open the Nonlinear Examples folder and then US Population.jmp.
2. Right-click the column name x-formula and select Formula.
3. In the middle pane of the Formula Editor, select Parameters from the list.
Notes:
• After completing a nonlinear fit or after clicking the Reset button in the nonlinear control panel, the parameter’s value is the most recent value computed by the nonlinear platform.
• Each time the fitting algorithm takes a step, the updated parameter values are shown in the Nonlinear report.
• When you paste a formula with parameters into a column, the parameters are automatically created for that column unless it has existing parameters with the same names.
• Double-clicking or pressing Alt and clicking the parameter replaces the portion of the formula that is selected.
• Pressing Alt+Shift and clicking enables you to edit the selected parameter in place instead of in a new window.
To build a formula that references values found in parameters
1. Open the Formula Editor by right-clicking a column name in the data table and selecting Formula.
2. Make sure the formula is selected in the formula editing area. (It is selected when there is a blue outline around it.)
3. In the middle pane of the Formula Editor, select Parameters from the list.
4. Click New Parameter.
5. Enter a name for the parameter. By default, parameters have the names b0, b1, and so on, and have missing values.
6. Assign a starting value. It is important to enter this value when using a parameter in a model for the nonlinear platform. After completing a nonlinear fit, the parameter’s value is the most recent value computed by the nonlinear platform.
7. (Optional) To add several parameters (one for each level of a categorical variable, for example) at once, select Expand into categories, selecting column. Then select the column for which you want to expand the parameter.
8. Click OK.
9. (Optional) To copy, edit, or delete a parameter, right-click (Ctrl-click on the macOS) its name and select Copy, Edit, or Delete.
1. Select a term in the formula editing area by clicking it. (It is selected when there is a blue outline around it.)
2. Click the parameter name in the Parameters box. The parameter appears in the formula as bold type.
Tip: Pressing Alt+Shift and clicking enables you to edit the selected parameter.