Specifying Get/Pay Expressions
You may specify get/pay expressions using the ribbon directly or through the Get/Pay tab of the Branch Definition dialog, which can be accessed by double-clicking on the appropriate branches in the decision tree.
Get/Pay expressions are used to calculate the value model as DPL evaluates the Decision Tree. A get expression is added to the value model; a pay expression is subtracted. You can get or pay more than one value by using an expression that contains sums or differences of the values. You can enter either simple numerical values or complex expressions as data. You can also enter previously defined variables or use DPL's functions. If you use the name of a node defined as a variable, you must enter it as DPL will use it internally, not as it appears in the node name. See Node Names for information on the possible differences.
To avoid typing the name of a variable or function, the Get/Pay group on the ribbon and the dialog offers lists of the previously defined variables and the functions supported by DPL. For information on entering variables or functions, see Entering Variables or Entering Functions.
If a node is symmetric, that is, the branches have one common endpoint, the same get/pay expression will be attached to all the branches. If a node is asymmetric or mixed, different get/pay expressions can be attached to each branch or each group of branches.
If your model doesn't contain any decision or chance nodes, DPL will ask you for an expression to use for the value model when you run the model.
Editing Get/Pay Expressions Using the Ribbon
- Select the branches in the Decision Tree you wish to modify.
- If you have a multiple attribute model, select the attribute for which you wish to modify the get/pay in the top Select Attribute drop-down in Decision Tree | Get/Pay group.
- Use the lower Edit Get/Pay drop-down within Decision Tree | Get/Pay group to select a variable for the get/pay expression or the Link Excel Metric option (see blow).
- If the get/pay expression contains multiple variables or functions, use the Select Variable button or Select Function button . Select the appropriate variable or function from the dialog and click OK.
- Use the radio button to show, hide or show an indicator ($) for the selected get/pay. See below.
Link Excel Metric
If the get/pay expression for a particular branch is going to include a linked value node that has not yet been added to the model, DPL can create this linked value node and add it as a get/pay expression to the selected branches for you by choosing the Link Excel Metric command from the lower Edit Get/Pay drop-down. This will launch the Range Names dialog, from which you can choose the desired metric. In addition to the selected branches, the value node will also be added to the Influence Diagram.
Editing Get/Pay Expressions in the Dialog
The Get/Pay tab of the Branch Definition dialog will only show one get or pay expression labeled Objective Function if your model does not have multiple attributes. If you see only one get or pay expression:
- Double-click on the magenta cell to enter or edit the expression.
- Use the variable and function buttons near the bottom or the dialog to edit the expression.
- Select Get or Pay depending on whether the expression should be added to or subtracted from your value model.
If you have multiple attributes, you will also see a row for each attribute, and you need to indicate an expression (or zero) in the Get or pay expression cell for each attribute. You can click the Go to Attributes button to see what the attributes are. See Multiple Attributes and Objective Functions for instructions on how to enter Get/Pay expressions for models with Multiple Attributes, and how to use the Fill Down button .
Hiding Get/Pay Expressions or Displaying an Indicator
The get/pay expression is displayed under the branch at the right end of it in the decision tree. If you wish to hide the get/pay or display only an indicator ($), you may do so by selecting the branches and using the radio buttons within the Decision Tree | Get/Pay group on the ribbon.
Versions: DPL Professional, DPL Enterprise, DPL Portfolio