Graphic Policy Trees
The default view for a Policy Tree is the graphic view. If the Policy Tree is in text view, uncheck Policy | Display | Text View to switch to the graphical view. By default, DPL will show only those decision paths that are optimal and only as many decision levels as needed to display all decision alternatives; other paths will be collapsed. If you have changed the detail level in text view, the graphic view will show the same detail level.
The optimal alternative of each decision is drawn with a heavier line. All computed probabilities and get/pay expressions are shown below the branches. Above the branches, objective function rollback values (expected values for subsequent parts of the tree) are shown in square brackets. If you have multiple attributes and you asked for Fat Policy, these attribute expected values are also displayed in the square brackets. If your model has multiple objective functions then the optimal decision alternative will be drawn in blue and the expected value of the objective function used at a particular decision point (specified within Node Definition | Tree Instance)will be blue as well.
You can change which data elements that are shown by using the commands within or launching the dialog box launcher for the Policy | Display group.
Changing the Detail Level of a Graphic Policy Tree
For complex problems, the Policy Tree can be quite large. DPL allows you to adjust the level of detail shown in the window to suit your needs. If you didn't request all policy levels when you ran the analysis, you may not be able to expand the tree fully (see Number of Policy Levels).
To expand the Policy Tree, double-click on a collapsed node (one that ends in a decision or chance node symbol rather than an endpoint) or select the node and choose Policy | Display | Expand or Expand and Zoom. This will by default, expand the tree from the selected node by one level and zoom full if Expand and Zoom was chosen. Note that once you have chosen other Expand options (Expand Subtree, Expand All, or Expand to Level), double-clicking a node or selecting a node and choosing Policy | Display | Expand or Expand and Zoom will expand the tree to the level previously chosen.
To expand the subtree from the selected node, choose Policy | Display | Expand Subtree. To expand the Policy Tree from the selected node to a specific number of policy levels, choose Policy | Display | Expand to Level, and enter the desired level in the Expand Policy Tree dialog. To expand all of the tree choose Policy | Display | Expand All. To collapse the Policy Tree, double-click on any expanded node, or select the node and choose Policy | Display | Collapse or Collapse and Zoom. All of the Zoom/Collapse commands are also available in the context menu for the Policy Tree when a node is selected. Shift+double-click expands/collapses and then does a Zoom Full to fit the Policy Tree to the window.
Displaying the Certain Equivalent-Based Policy
To display the certain equivalent-based policy, turn on View | Results | CE. If your model does not include a utility function, the CE option will not be available.
Displaying Multiple Objective Functions (DPL Enterprise)
For models with multiple objective functions the Policy Tree will indicate which objective function was used to evaluate a particular decision by displaying the expected value for that objective function in blue. You'll also note that the bolded lines are also shaded in blue. You can choose which, if any, objective functions expected values to display in the Policy Tree within the Format Policy Tree dialog.
Formatting and Viewing a Graphic Policy Tree
In terms of graphical functionality, the Policy Tree graphic window is very similar to the Decision Tree drawing window. You can use the mouse or zoom options to zoom in on particular areas of the tree (see the Model Window). You can change the diagram text formatting via the View | Font group. You can also add, change, and format text blocks using the View | Layout and View | Font groups.
Printing a Graphic Policy Tree
To print a graphic Policy Tree, choose File | Print. See Printing.
Copying a Graphic Policy Tree to Other Applications
To copy a graphic Policy Tree to other Windows applications, use Home | Edit | Copy or Ctrl+C.
Versions: DPL Professional, DPL Enterprise, DPL Portfolio