Nonlinear Regression Parameters
Parameters are the parts of your model that the Nonlinear Regression procedure estimates. Parameters can be additive constants, multiplicative coefficients, exponents, or values used in evaluating functions. All parameters that you have defined will appear (with their initial values) on the Parameters list in the main dialog box.
Name. You must specify a name for each parameter. This name must be a valid variable name and must be the name used in the model expression in the main dialog box.
Starting Value. Allows you to specify a starting value for the parameter, preferably as close as possible to the expected final solution. Poor starting values can result in failure to converge or in convergence on a solution that is local (rather than global) or is physically impossible.
Use starting values from previous analysis. If you have already run a nonlinear regression from this dialog box, you can select this option to obtain the initial values of parameters from their values in the previous run. This permits you to continue searching when the algorithm is converging slowly. (The initial starting values will still appear on the Parameters list in the main dialog box.)
Note: This selection persists in this dialog box for the rest of your session. If you change the model, be sure to deselect it.
Specifying Nonlinear Regression Parameters
This feature requires the Regression option.
- From the menus choose:
- In the Nonlinear Regression dialog box, click Parameters.
- Enter a name for the parameter. This name must be a valid variable name and must be the name used in the model expression in the main dialog box.
- Enter a starting value for the parameter, preferably as close as possible to the expected final solution. Poor initial values can result in failure to converge or in convergence on a solution that is local (rather than global) or is physically impossible.
- After specifying a name and starting value, click Add to add the parameter to the Parameters list.