Package edu.cmu.tetrad.search.utils

Class DagSepsets

java.lang.Object

edu.cmu.tetrad.search.utils.DagSepsets

All Implemented Interfaces:

SepsetProducer

public class DagSepsets
extends Object
implements SepsetProducer

Determines sepsets, collider, and noncolliders by examining d-separation facts in a DAG.

Version:

$Id: $Id

Author:

josephramsey

Constructor Summary

Constructors

Constructor	Description
DagSepsets(Graph dag)	Constructs a new DagSepsets object for the given DAG.

Method Summary

Modifier and Type	Method	Description
Graph	getDag()	Returns the DAG being analyzed.
double	getPValue(Node a, Node b, Set<Node> sepset)	Calculates the p-value for a statistical test a _||_ b | sepset.
double	getScore()	Returns the score of the object.
Set<Node>	getSepset(Node a, Node b, int depth)	Retrieves the sepset, which is the set of common neighbors between two given nodes.
Set<Node>	getSepsetContaining(Node a, Node b, Set<Node> s, int depth)	Returns the sepset containing nodes 'a' and 'b' that also contains all the nodes in the given set 's'.
List<Node>	getVariables()	Retrieves the list of variables.
boolean	isIndependent(Node a, Node b, Set<Node> sepset)	Checks if node d is independent of node c given the set of nodes in sepset.
boolean	isUnshieldedCollider(Node i, Node j, Node k, int depth)	isUnshieldedCollider.
void	setGraph(Graph graph)	Sets the graph for the SepsetProducer object.
void	setVerbose(boolean verbose)	Sets the verbose mode of the SepsetProducer.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DagSepsets

public DagSepsets(Graph dag)

Constructs a new DagSepsets object for the given DAG.

Parameters:

dag - the DAG.

Method Details

getSepset

public Set<Node> getSepset(Node a,
 Node b,
 int depth)

Retrieves the sepset, which is the set of common neighbors between two given nodes.

Returns the list of sepset for {a, b}.

Specified by:

getSepset in interface SepsetProducer

Parameters:

a - the first node

b - the second node

depth - the depth of the search

Returns:

the set of common neighbors between nodes a and b

getSepsetContaining

public Set<Node> getSepsetContaining(Node a,
 Node b,
 Set<Node> s,
 int depth)

Returns the sepset containing nodes 'a' and 'b' that also contains all the nodes in the given set 's'. Note that for the DAG case, it is expected that any sepset containing 'a' and 'b' will contain all the nodes in 's'; otherwise, an exception is thrown.

Specified by:

getSepsetContaining in interface SepsetProducer

Parameters:

a - The first node.

b - The second node.

s - The set of nodes that must be contained in the sepset.

depth - The depth of the search.

Returns:

The sepset containing 'a' and 'b' that also contains all the nodes in 's'.

Throws:

IllegalArgumentException - If the sepset of 'a' and 'b' does not contain all the nodes in 's'.

isUnshieldedCollider

public boolean isUnshieldedCollider(Node i,
 Node j,
 Node k,
 int depth)

isUnshieldedCollider.

True iff i*-*j*-*k is an unshielded collider.

Specified by:

isUnshieldedCollider in interface SepsetProducer

Parameters:

i - a Node object

j - a Node object

k - a Node object

depth - the depth of the search

Returns:

a boolean

getScore

public double getScore()

Returns the score of the object.

Not implemented; required for an interface.

Specified by:

getScore in interface SepsetProducer

Returns:

the score value

isIndependent

public boolean isIndependent(Node a,
 Node b,
 Set<Node> sepset)

Checks if node d is independent of node c given the set of nodes in sepset.

Returns true just in case msep(a, b | c) in the DAG. Don't let the name isIndependent fool you; this is a d-separation method. We only use the name isIndependent so that this can be used in place of an independence check.

Specified by:

isIndependent in interface SepsetProducer

Parameters:

a - the first node

b - the second node

sepset - the set of common neighbors between d and c

Returns:

true if d is independent of c, false otherwise

getPValue

public double getPValue(Node a,
 Node b,
 Set<Node> sepset)

Description copied from interface: SepsetProducer

Calculates the p-value for a statistical test a _||_ b | sepset.

Specified by:

getPValue in interface SepsetProducer

Parameters:

a - the first node

b - the second node

sepset - the set of nodes

Returns:

the p-value for the statistical test

Throws:

UnsupportedOperationException - if this method is called.

setGraph

public void setGraph(Graph graph)

Description copied from interface: SepsetProducer

Sets the graph for the SepsetProducer object.

Specified by:

setGraph in interface SepsetProducer

Parameters:

graph - the graph to set

getVariables

public List<Node> getVariables()

Retrieves the list of variables.

Returns the nodes in the DAG.

Specified by:

getVariables in interface SepsetProducer

Returns:

the list of variables as a List of Node objects.

setVerbose

public void setVerbose(boolean verbose)

Sets the verbose mode of the SepsetProducer.

Thsi method is not used.

Specified by:

setVerbose in interface SepsetProducer

Parameters:

verbose - true if verbose mode is enabled, false otherwise

getDag

public Graph getDag()

Returns the DAG being analyzed.

Returns:

This DAG.