Class Node

Represents a node with one or more variables in a Bayesian network.

Inheritance

System.Object

Node

Implements

System.ComponentModel.INotifyPropertyChanged

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

Namespace: BayesServer

Assembly: BayesServer.dll

Syntax

public sealed class Node : INotifyPropertyChanged

Remarks

Note that node names must be unique per network, and are case sensitive.

To specify a distribution for a node, see the Distribution property.

To add a directed link between two nodes, it must be added through the Network.Links property.

Constructors

Node()

Initializes a new instance of the Node class, with no variables, and no name.

Declaration

public Node()

Node(Variable)

Initializes a new instance of the Node class with a specified Variable and assigns the name of the variable to the node.

Declaration

public Node(Variable variable)

Parameters

Type	Name	Description
Variable	variable	A single variable for the node.

Node(String, State[])

Initializes a new instance of the Node class, with the name of the node, automatically creating an associated discrete Variable and adds the states specified in states to that variable.

Declaration

public Node(string name, params State[] states)

Parameters

Type	Name	Description
System.String	name	The name of the node and variable.
State[]	states	The states to add to the associated Variable.

Exceptions

Type	Condition
System.ArgumentNullException	Raised when `states` is null.

Node(String, Variable[])

Initializes a new instance of the Node class with a specified name and a number of variables.

Declaration

public Node(string name, params Variable[] variables)

Parameters

Type	Name	Description
System.String	name	The name for the node.
Variable[]	variables	The variable(s) represented by the node.

Node(String, VariableValueType)

Initializes a new instance of the Node class with the specified name. A Variable is automatically created for the node and assigned the same name as the node with the VariableValueType specified.

Declaration

public Node(string name, VariableValueType valueType)

Parameters

Type	Name	Description
System.String	name	The name to give the node and variable, which can be null or empty.
VariableValueType	valueType	The VariableValueType of the node variable, e.g. discrete or continuous.

Node(String, VariableValueType, VariableKind)

Initializes a new instance of the Node class with the specified name. A Variable is automatically created for the node and assigned the same name as the node with the VariableValueType specified.

Declaration

public Node(string name, VariableValueType valueType, VariableKind kind)

Parameters

Type	Name	Description
System.String	name	The name to give the node and variable, which can be null or empty.
VariableValueType	valueType	The VariableValueType of the node variable, e.g. discrete or continuous.
VariableKind	kind	The kind of variable, e.g. Probability (standard), Decision or Utility.

Node(String, IList<Variable>)

Initializes a new instance of the Node class with a specified name and a number of variables.

Declaration

public Node(string name, IList<Variable> variables)

Parameters

Type	Name	Description
System.String	name	The name for the node.
System.Collections.Generic.IList<Variable>	variables	The variable(s) represented by the node.

Node(String, Int32)

Initializes a new instance of the Node class with the specified name and automatically adds a discrete Variable with the number of states specified in states.

Declaration

public Node(string name, int states)

Parameters

Type	Name	Description
System.String	name	The name to give the node and variable, which can be null or empty.
System.Int32	states	The number of states to add to the automatically created Variable. States will be given default names.

Exceptions

Type	Condition
System.ArgumentOutOfRangeException	Raised when the `states` parameter is less than zero.

Node(String, String[])

Initializes a new instance of the Node class, with the name of the node, automatically creating an associated discrete Variable and adds the states specified in states to that variable.

Declaration

public Node(string name, string[] states)

Parameters

Type	Name	Description
System.String	name	The name of the node and variable.
System.String[]	states	The states to add to the associated Variable, specified by their names.

Exceptions

Type	Condition
System.ArgumentNullException	Raised when `states` is null.

Properties

Bounds

Gets or sets the size and location of the node.

Declaration

public Bounds Bounds { get; set; }

Property Value

Type	Description
Bounds	The size and location of the node.

CausalObservability

The CausalObservability of the node. The default value is Observable.

Declaration

public CausalObservability CausalObservability { get; set; }

Property Value

Type	Description
CausalObservability

CustomProperties

Gets custom properties associated with this instance.

Declaration

public CustomPropertyCollection CustomProperties { get; }

Property Value

Type	Description
CustomPropertyCollection

Remarks

Custom properties allow storage of custom information, which will be saved with the network.

Description

An optional description for the node.

Declaration

public string Description { get; set; }

Property Value

Type	Description
System.String

Distribution

Returns the distribution currently associated with the Node. The distribution cannot be modified when it is assigned to a node. It is also automatically set to null, when certain structural changes occur (see remarks).

Declaration

public IDistribution Distribution { get; set; }

Property Value

Type	Description
IDistribution

Remarks

If a structural change occurs to the network that invalidates the current distribution, it is automatically set to null. This occurs in the following situations:

States are added or removed from the node.
States are added or removed from one of the node's parents.
The LinksIn collection changes. I.e. adding or removing a parent node. Note that if a node is removed from a network, all of its links are automatically removed also.

Exceptions

Type	Condition
System.ArgumentException	Raised when the distribution is invalid.

DistributionOptions

Options that apply to all distributions of this instance.

Declaration

public NodeDistributionOptions DistributionOptions { get; }

Property Value

Type	Description
NodeDistributionOptions

Distributions

Returns the distributions associated with this instance with NodeDistributionKind = Probability. Some node types such as temporal nodes can have more than one distribution assigned to them.

Declaration

public NodeDistributions Distributions { get; }

Property Value

Type	Description
NodeDistributions

Groups

Gets the groups this node belongs to.

Declaration

public NodeGroupCollection Groups { get; }

Property Value

Type	Description
NodeGroupCollection

Index

The Index of this instance in the collection of nodes belonging to a network, or -1 if the node does not belong to a network.

Declaration

public int Index { get; }

Property Value

Type	Description
System.Int32

Links

Collection of both incoming and outgoing links (parent and child nodes).

Declaration

public NodeLinkCollection Links { get; }

Property Value

Type	Description
NodeLinkCollection

LinksIn

Collection of incoming links (linking to parent nodes).

Declaration

public NodeLinkCollection LinksIn { get; }

Property Value

Type	Description
NodeLinkCollection

LinksOut

Collection of outgoing links (linking to child nodes).

Declaration

public NodeLinkCollection LinksOut { get; }

Property Value

Type	Description
NodeLinkCollection

Name

The name of the node. Node names in a network must be unique, and comparisons are case sensitive.

Declaration

public string Name { get; set; }

Property Value

Type	Description
System.String

Network

The Network the node belongs to. Value will be null unless the node has been added to a network.

Declaration

[Browsable(false)]
public Network Network { get; }

Property Value

Type	Description
Network

TemporalType

The TemporalType of the node. The default value is Contemporal.

Declaration

public TemporalType TemporalType { get; set; }

Property Value

Type	Description
TemporalType

Exceptions

Type	Condition
System.InvalidOperationException	Raised if the node belongs to a network, in which case the TemporalType cannot be changed.

Variables

Collection of variables represented by the node.

Declaration

public NodeVariableCollection Variables { get; }

Property Value

Type	Description
NodeVariableCollection

Methods

Copy()

Makes a copy of this instance.

Declaration

public Node Copy()

Returns

Type	Description
Node	The copy.

Remarks

The copy does not include links or distribution(s).

NewDistribution()

Creates a new distribution suitable for the node, however does not assign it to the node's Distribution property.

Declaration

public IDistribution NewDistribution()

Returns

Type	Description
IDistribution	A new distribution.

Remarks

This method is useful for creating distributions appropriate for a node. However, the returned distribution cannot be set to Distribution until the distribution has been correctly specified.

Note: if the resulting distribution contains continuous variables, but no discrete head variables, all table values are initialized to 1.

Exceptions

Type	Condition
System.ArgumentException	Raised if the node or one of it's parents has zero states.

NewDistribution(NodeDistributionKey)

Creates a new distribution suitable for the requested temporal order/related node, however it is not assigned to the node. Use Distributions to perform the assignment.

Declaration

public IDistribution NewDistribution(NodeDistributionKey key)

Parameters

Type	Name	Description
NodeDistributionKey	key	Identifies the order/related node for the requested distribution.

Returns

Type	Description
IDistribution	The new distribution.

Remarks

See NodeDistributions for more information.

Note: if the resulting distribution contains continuous variables, but no discrete head variables, all table values are initialized to 1.

A noisy node is specified using multiple distributions, one for each parent and a leak distribution. Set the related node property to a parent, or set it to the current node to set the leak distribution. Each distribution corresponding to a parent of the noisy node has a number of constrained values which are not parameters. These are automatically set by newDistribution (see the help for noisy nodes in the main documentation for more detail).

NewDistribution(NodeDistributionKey, NodeDistributionKind)

Creates a new distribution suitable for the requested temporal order/related node, however it is not assigned to the node. Use Distributions to perform the assignment.

Declaration

public IDistribution NewDistribution(NodeDistributionKey key, NodeDistributionKind kind)

Parameters

Type	Name	Description
NodeDistributionKey	key	Identifies the order/related node for the requested distribution.
NodeDistributionKind	kind	The kind of distribution to create.

Returns

Type	Description
IDistribution	The new distribution.

Remarks

See NodeDistributions for more information.

Note: if the resulting distribution contains continuous variables, but no discrete head variables, all table values are initialized to 1.

Experience table entries are also initialized to 1.

NewDistribution(NodeDistributionKey, NodeDistributionKind, IDistributionExpression)

Creates a new distribution from an expression suitable for the requested temporal order/related node, however it is not assigned to the node, and neither is the expression. Use BayesServer.Node.Distributions.Expressions to perform the assignment from an expression.

Declaration

public IDistribution NewDistribution(NodeDistributionKey key, NodeDistributionKind kind, IDistributionExpression expression)

Parameters

Type	Name	Description
NodeDistributionKey	key
NodeDistributionKind	kind
IDistributionExpression	expression

Returns

Type	Description
IDistribution	The new distribution.

Remarks

See Expressions for more information.

Identifies the order/related node for the requested distribution. The kind of distribution to create. The expression that should be used to generate the distribution.

NewDistribution(NodeDistributionKind)

Creates a new distribution with the given kind, however it is not assigned to the node. Use Distributions to perform the assignment. For temporal or noisy nodes us a different overload.

Declaration

public IDistribution NewDistribution(NodeDistributionKind kind)

Parameters

Type	Name	Description
NodeDistributionKind	kind	The kind of distribution to create.

Returns

Type	Description
IDistribution	The new distribution.

Remarks

See NodeDistributions for more information.

Note: if the resulting distribution contains continuous variables, but no discrete head variables, all table values are initialized to 1.

NewDistribution(Int32)

Creates a new distribution suitable for the requested temporal order, however it is not assigned to the node. Use Distributions to perform the assignment.

Declaration

public IDistribution NewDistribution(int temporalOrder)

Parameters

Type	Name	Description
System.Int32	temporalOrder	The order for the requested distribution.

Returns

Type	Description
IDistribution	The new distribution.

Remarks

See NodeDistributions for more information.

Note: if the resulting distribution contains continuous variables, but no discrete head variables, all table values are initialized to 1.

ToString()

Returns the name of the node, or an empty string if the name is null.

Declaration

public override string ToString()

Returns

Type	Description
System.String	A System.String containing the name of the node which is empty if the name is null.

Overrides

System.Object.ToString()

Events

PropertyChanged

Declaration

public event PropertyChangedEventHandler PropertyChanged

Event Type

Type	Description
System.ComponentModel.PropertyChangedEventHandler

Implements

System.ComponentModel.INotifyPropertyChanged