Specifying Output Variables
You can define output variables to use calculated expressions of results as adaptive convergence goals and for reports. You can use output variables in the Expression Cache tab of the Solution Setup dialog box and select them as Categories in the Reports dialog box, as well as the Output Variables window.
Access the Output Variables window one of several ways:
- Click
- In the Project Manager, right-click Results and select Output Variables from the shortcut menu.
- In the Solution Setup dialog box, select the Expression Cache tab, click Add... to display the Add to expression cache dialog box, and click the Output Variables button.
- Click the Output Variables button in the Report dialog box.
The Output Variables window contains four sections:
- Output Variables – contains a list of existing output variables, and allows you to specify the name and expression for a new output variable. The Validate output variable... check box allows you to validate an expression before adding it. Valid expressions appear in blue and invalid expressions appear in red.
- Context – specifies the
Report Type and Solution. Depending on the type of report selected, additional fields may appear. All
selections affect the functions and quantities listed.
Note:
The context is used only for generating expressions.
- Quantities – allows you to insert quantities into the Expression area of the Output Variables section.
- Function – allows you to insert completed expressions into the Expression area of the Output Variables section.
To add an output variable:
- Enter a Name for the variable.
- Specify the Context. This impacts the available quantities and functions.
- Specify the Quantities (required) and Functions (optional) using the Insert Into Expression buttons.
- Review the Expression. When it is ready, click Add.
The new output variable appears in the Output Variables list.
To delete an output variable:
- Remove all references to the output variable from the project.
- Save the project to erase the command history.
- Open the Output Variables window using one of the methods above.
- Select the variable from the Output Variables list and click Delete.
The evaluated value of an expression is always interpreted in SI units. However, when an angle quantity is plotted in a report, you have the option to plot values in units other than SI. For example, if you want to plot the polar angle of a complex simulation result S11, you can choose between ang_deg(S11) and ang_rad(S11). Both of these return the exact same angle quantity, but in degree and radian units respectively.
When using non-SI units in expressions, surprising outcomes might result. For example, the expression 1+ang_deg(S11) represents an angle and the number 1 is treated as 1 rad. The angle SI unit is attached to any unitless number that is added/subtracted from an angle value. If you want to treat 1 as degrees, make it explicit and use 1deg + ang_deg(S11) instead.
If you are interested in unitless degree values, two additional functions exist: ang_deg_val(S11) and cang_deg_val(S11). These return simple numbers and are treated as such by any expression. For example, if the complex S11 lies on the positive Y axis, ang_deg_val(S11) would be 90 and 1 + ang_deg_val(S11) would be 91.