Links in a Bayesian network or Dynamic Bayesian network, indicate that the variable(s) in one node, influence the variable(s) in the other.
The distribution for a node, depends on the incoming links of a node. More specifically,
the distribution for a node
A is the conditional probability
Add a new link
To add a new link to a Bayesian network or Dynamic Bayesian network, select a node in the From drop down and a node in the To drop down.
The Ellipsis buttons allow one or more nodes to be selected from a list if you want to add multiple links at once, and also allows sorting and filtering which is useful when the network contains a large number of nodes.
The Delete button clears the currently selected node(s).
The Swap button located between the two drop downs, changes the From node(s) to the To node(s), and vice versa.
When ready, click OK to add the link(s).
This operation can be undone, by clicking the Undo button on the main window.
When a link is added, the variables in a node's distribution change. If distributions have been specified before the link is added, the behavior depends on the option Migrate Existing Distributions.
When creating a link between two temporal nodes in a Dynamic Bayesian network, a Temporal Order must be specified. A temporal order indicates that the From node links to the To node at a future time. A value of zero, indicates that they are linked at the same time.
The From node and To node, can be the same node, if the node is a Temporal node, and the temporal order is greater than zero.
Multiple links can be created between two temporal nodes (including the same node) if the temporal order is different.
To add multiple links with different orders in a single operation, the Range option can be set to true, allowing the input of a minimum and maximum order. Multiple links will then be added, from the minimum to the maximum order (inclusive).
While a link can be specified from a Discrete node to a Continuous node, the reverse is not true. i.e. a link cannot be specified from a Continuous node to a discrete node.