Link

A link in a Bayesian network defines a causal link from one chance node (discrete or continuous) to another.

In an influence diagram, a link can mean one of three things:

  1. It can be a causal link as in a pure Bayesian network. This is the case, when the link goes from a chance node or decision node to a chance node.
  2. It can define the utility function to depend on a chance node or a decision node. This is the case if the link goes from a chance node or decision node to a utility node.
  3. It can define the order of the decision nodes (See the Decision Node section for more about the order of decision nodes). This is the case if the link goes from a chance node or decision node to a decision node.

In an object-oriented Bayesian network (or influence diagram), a link is defined as above, except if the link points to an input node of an instance node.  In that case the link is interpreted as a binding link (i.e., the input node is bound to the node at the other end of the link).

A link can be established in Edit Mode by activating the Link Tool and dragging a line from one node to another.

There are three different display modes for a link:

The display mode for a link is selected by first selecting the link (i.e., left-click at or near the link so it gets highlighted), then right-clicking at the background of the Network Pane to activate the pop-up menu for the pane, then selecting the Link Mode item, and finally selecting the desired mode from the Link Mode sub-menu (see Figure 1).

Figure 1: There are three different display modes for a link.

New bezier points a created simply by click-and-drag operations. Figure 2 shows a link with two bezier points, displayed in Spline mode and Lines mode, respectively. The bezier points can be moved using click-and-drag operations. Please note that if a bezier point is moved to a location lying on the line between its neighboring points, it will be removed.

        

Figure 2: There are three different display modes for a link.


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