Menu: Node menu

From DSL

The Node menu offers the following commands:

• Node properties

The Node properties command is active only if there is one (and only one) node selected in the Graph view. It invokes the Node Property sheet for the selected node. The Node Properties sheet can also be invoked by right clicking a particular node and selecting Node Properties from the popup menu.

• Change Type SubMenu

This command allows the user to change the type of the selected node. It opens up the Change Type sub menu shown below:

You can select any of the displayed types of nodes to change the type of the selected node. See Node Types section for more information on the node types available.

• Set evidence / Set decision submenu

The Set evidence / Set decision submenu is active only if there is one (and only one) node selected in the Graph view. If that node is a Chance or Deterministic node, the text Set evidence appears in the menu. If the node is a Decision node, the text Set decision appears. The Set evidence / Set decision submenu allows you to see the states of the selected node and set one of them as the observed value.

To select a state of the currently selected node, select this state on the submenu listing the states and release the mouse button. The state will have a check mark next to its name. The node will from that point on be equipped with the (Observed) status icon, indicating that one of the states of this node has been observed. If the node was equipped with the (Invalid) status icon, the icon will disappear (please note that the value of an observed node is known and it is, therefore, valid). To change the node back to the unobserved state, choose Clear evidence from the Node menu.

• Control Value

The Control Value submenu is active only if there is one (and only one, having a causal relationship with a parent ) node selected in the Graph view. It is not available for Decision and Value type nodes. This command lets you to force a particular state for the node independent of its causal relationship with its parents. A node that is controlled is indicated by the (Control) Status Icon and the dimming of the arcs connecting the node to its parents. The Control Value submenu allows you to see the states of the selected node and set one of them as controlled.

To select a state of the currently selected node, select this state on the submenu listing the states and release the mouse button. The state will have a check mark next to its name. The node will from that point on be equipped with the (Controlled) status icon, indicating that one of the states of this node has been observed. If the node was equipped with the (Invalid) status icon, the icon will disappear. To change the node back to the original state, choose Release Value from the Node menu. See Using Control Values section in GeNIe Tutorials for more information on how to use this in your model.

• Clear evidence / Release Value

The Clear evidence / Release Value command is active only if there is one (and only one) node selected in the Graph view and one of the states of this node has been previously observed or controlled. Clear evidence un-observes a state, i.e., it reverses the effect of the Set evidence command. Release Value un-controls a state, i.e., it reverses the effect of the Control Value command. The check mark next to the state name will disappear. The (Observed) status icon / (Controlled) status icon will disappear and possibly the (Invalid) status icon will appear.

• Set target

The Set target command is active only if there is one (and only one) node selected in the Graph view. It allows you to set the status of the node to be Target. The node will from that point on be equipped with the (Target) status icon, indicating that the node is a target (i.e., its value or the probability distribution over its possible values are of interest to the user).

• Clear target

The Clear target command is active only if there is one (and only one) node selected in the Graph view and it is marked as a target. Clear target reverses the effect of the Set target command. The (Target) status icon will disappear.

• View As..

The View As submenu controls how the nodes are displayed in the Graph View.

The Icon option displays the node as an elliptical or polygonal shape [ depending on node type ]. The probability distribution for the states can be viewed by updating the model and placing the cursor over the (Updated) status icon.

The Bar Chart option displays the node as a Barchart of the probabilities of each state of the node. This view is useful when we want to see the probabilities at a glance.

If a decision has been made , it will be highlighted in bold in the bar view and displayed as below:

• Locate Parent

This command can be used to locate the Parent of the selected node. If there is more than 1 parent, then it will display a list of all parents of the selected node. Select one of the parents to locate it in the Graph View. Once located, the node is flashed on the screen.

• Locate Child

This command can be used to locate the children of the selected node. If there is more than 1 child, then it will display a list of all children of the selected node. Select one of the children to locate it in the Graph View. Once located the node is flashed on the screen.