# Function Node

A function node represents a real-valued function that depends on (some or all of) the parents of the node. Function nodes are not (directly) involved in the inference process - evidence cannot be specified for function nodes, but the function associated with the node can be evaluated using the results of inference or simulation as input. Add a Function node by using the Function Tool.

Figure 1: A Function node (F1) with a discrete and a continuous parent.

Function node values are specified as an expression in the node model. A number of rules apply for Function Nodes:

- If Function node has non-function node children, there must not exist a cyclic functional dependency such that one of the function node ancestors depends on the value of the function node.

- Function value expressions can use parent Function-, Boolean-, Numbered- and Continuous node values. (currently Interval nodes are not supported).

- When a Continuous node appear in the expression, the mean of the node is used when computing the function value.