To enable this option in the context menu, click the Show More Options button () and select Sensitivity in the Show More Options dialog box.

Use the Sensitivity () study step to add a sensitivity analysis to the study. Using a Sensitivity study node, you can add sensitivity functions at the study level and use model parameters as global control variables. Compared to The Sensitivity Interface, the Sensitivity study step has these capabilities:

The Settings window has the following sections:

Choose a method from the Gradient method list: one of the analytical methods Forward or Adjoint (the default). See Choosing a Sensitivity Method for information about the forward and adjoint methods. These methods have similar limitations as the gradient-based optimization methods (MMA, IPOPT, SNOPT and Levenberg-Marquardt). For example, nonanalytic functions are not correctly treated. Also, when model parameters are used in the geometry or mesh, the sensitivity is not correctly computed.

You choose the study step to use from the Study step list, which contains None and any supported study steps in the study. Supported types are those for which the default solver is a Stationary Solver or a Time-Dependent Solver. Note that this includes the Frequency Domain study step, which uses a stationary solver. Click the Go to Source button ) to move to the Settings window for the selected study node.

You specify the objective function for the optimization problem in the table’s Expression column. Enter any globally available expression that evaluates to a real number. Optionally, you can add a description in the Description column. Click the Add Expression () and Replace Expression () buttons to search through a list of predefined expressions.

If you have defined more than one objective function, choose how to evaluate the overall objective: For sensitivity studies, only Sum of objectives is available.

Here you select the evaluation method of the objective function when several solutions are present, like for Time Dependent studies. For sensitivity studies, only Auto is available. The solver chooses the evaluation method based on the innermost study. For a Time Dependent study, the optimization solver selects the last solution (final time).

The table under Control Variables and Parameters is used to define control variables. In this table you can select all parameters defined in the Global Definitions>Parameters node’s Settings window through the Add () button.

From a list in the Parameter name column, select the parameter to define as a control variable. You can then give it a value and scale as a control variable in the Value and Scale columns, respectively. If the control value is complex-valued, select Complex from the list in the Value type column (the default is Real).

Move control parameter rows up and down using the Move Up () and Move Down () buttons. To remove a control parameter, select some part of that parameter’s row in the table and click the Delete button ().

You can also save the definitions of the control parameters to a text file by clicking the Save to File button () and using the Save to File dialog box that appears. To load a text file with control variables, click the Load from File button () and use the Load from File dialog box that appears. Data must be separated by spaces or tabs.