.. index:: Node

.. _Node_Category:

Node
====

The *nodes* are one of the basics in constructing a HUGIN network (:ref:`Bayesian network<About_Bayesian_Network>`, :ref:`LIMID<About_Limited_Memory_Influence_Diagram>`, or :ref:`object-oriented network<Object_oriented_network>`). Currently, HUGIN has five types of nodes that differ in appearance and semantics.

* :ref:`Discrete Chance Nodes<discrete_chance_node>` - represent random variables with a discrete finite state space.
* :ref:`Continuous Chance Nodes<continuous_chance_node>` - represent random variables with a continuous infinite satet space having a Gaussian (normal) distribution.
* :ref:`Decision Nodes<decision_node>` - represent decisions or actions with a discrete state space.
* :ref:`Utility Nodes<utility_node>` - represent the utility function one or more decisions are to be compared on.
* :ref:`Instance Nodes<instance_node>` - represent instances of other networks, enabling object-oriented specification of networks (both Bayesian networks and influence diagrams).
* :ref:`Function Nodes<function_node>` - computes a value based on expressions

The graph of a network consist of the nodes and the :ref:`links<link_label>`.