User`s guide

8 Model Analysis

3 Select Regressor 1 from th e list of available regressors. In the Range

ﬁeld, enter the range of v alues to include on the plot for this regressor. The

regressor values are plotted on the Reg1 ax is.

4 Specify a second regressor for a 3-D plot by selecting one of the following

types of options:

• Select R e gr essor 2 to display three axes. In the Range ﬁeld, enter the

range of values to include on the plot for this regressor. The regressor

values are plotted on the Reg2 axis.

• Select

<none> in the Regressor 2 list to display only tw o axes.

5 To ﬁx the values of the regressor that are not displayed, click Fix Values.

In the Fix Regressor Va lues d ia log box , double-click the Value cell to edit

the constant value of the corresponding regresso r. The d efault values are

determined during model estimation. Click OK.

6 In the Nonlinear ARX Model Plot window, click Apply to update the plot.

7 To change the grid of the regressor space along each axis, Options > Set

number of samples, and enter the number of samples to use for each

regressor. Click A pply and then Close .

For example, if the number of samples is 20, each regressor variable

contains 20 points in its speciﬁed range. For a 3-D plots, this results in

evaluating the nonlinearity at 20 x 20 = 400 points.

Axis Limits, Legend, and 3-D Rotation

The following table summarizes the commands to modify the appearance

of the Nonlinear ARX plot.

Changing Appearance of the Nonlinear ARX Plot

Action

Command

Change axis limits. Select Options > Set axis limits to

open the Axis Limits d ialog b ox, and

edit the lim its. Click Apply.

8-54