Compound output parameters

The compound output parameters are displayed in a list with two fields, as show in the figure below.

Figure 62: List of compound output parameters

Adding compound output parameters

Compound outputs adding

Compound output parameters are computed using an expression that you supply. The expression can be any valid combination of:

• Simple output parameters,

• Input parameters,

• other compound output parameters,

• simple mathematical functions,

• special export functions.

Simple mathematical functions are things like sin, exp, abs etc.

The full list of special export functions and a description of each is given in Description of export and post-processing functions.

In order to add a new compound output parameter, go through the following steps:

Procedure

1. If necessary select Configure > Study parameters or click the Study parameters button from the mode contextual toolbar.

The Study Manager opens. Ensure the Parameters tab is selected.

2. Go to the Compound outputs table and click the Add button.

A new line appears in the list.

Removing compound output parameters

Compound output removing

To remove a parameter from the Compound outputs:

• right-click on it and select Remove,

• select it in the list and click the Remove button, or,

• select it in the list and press the Del key.

Compound output parameter properties

Once the compound output parameters have been added, their properties have to be set. The following section details the properties that define a compound output parameter.

• Name: This is the same as for Input parameters: see Input parameters.

• Compound outputs expression Expression: This property is needed in order to compute the output.Note See Description of the Expression Editor functions in the Simcenter Amesim Reference Manual for more information on the syntax of mathematical functions. To change the expression, click twice on the corresponding cell. You then enter edit mode. There are two ways to set the new expression:

If it is simple, you can just type in the new expression and validate it by pressing the Enter key.

Click the ... button on the right-hand side of the edited cell. The Expression Editor opens, in which you can build the expression. However, please note that the expression editor that opens for the Study Manager contains certain enhancements, as shown in the figure below.

Figure 63: Special Expression Editor for Study Manager

Expression evaluation rules

Compound outputs expression evaluation rules

At run time, the following rules are applied to evaluate the expression:

• For input parameters, the value used is the one used to perform the simulation (e.g. the one you set or the default one).

• For simple output parameters: unless you specify something else (using the valueat function for instance) the value used is the value of the corresponding variable at the end of the simulation.

• For compound output parameters, the value used is the result of evaluating the corresponding expression.

• Some specific functions consider all the values taken by a variable during the simulation period. If such function is applied to a compound output parameter, this compound output parameter will have to be evaluated for each simulation communication time.

Results

Under some circumstances, it is impossible to compute a compound output parameter. In this case, the result is said to be undefined and then all compound output parameters which use it are also undefined.

Finally, note that even an integer input parameter is considered as real when used in an expression.