gov.sandia.cognition.graph.inference

Interface EnergyFunction<LabelType>

Type Parameters:

LabelType - This type allows for the labels to be any object type or enum

All Known Subinterfaces:

NodeNameAwareEnergyFunction<LabelType,NodeNameType>

All Known Implementing Classes:

CostSpeedupEnergyFunction, EdgeMergingEnergyFunction, GraphWrappingEnergyFunction

public interface EnergyFunction<LabelType>

This interface defines the methods necessary for an object to be passed into an iterative message-passing data inferencing solver (such as belief propagation).

Author:

jdwendt

Method Summary

Modifier and Type	Method and Description
Pair<java.lang.Integer,java.lang.Integer>	getEdge(int i) Returns the indices for the two endpoints in the specified path.
double	getPairwiseCost(int edgeId, LabelType ilabel, LabelType jlabel) This is the -log(getPairwisePotential(.)).
double	getPairwisePotential(int edgeId, LabelType ilabel, LabelType jlabel) Returns the pairwise cost of node i being assigned label_i and node j being assigned label_j.
java.util.Collection<LabelType>	getPossibleLabels(int nodeId) Returns the set of labels that this message passer supports
double	getUnaryCost(int i, LabelType label) This is the -log(getUnaryPotential(.)).
double	getUnaryPotential(int i, LabelType label) Returns the unary cost for node i having the input label.
int	numEdges() Returns the number of paths that messages should be passed down.
int	numNodes() Returns the number of nodes in the energy function.

Method Detail

getPossibleLabels

java.util.Collection<LabelType> getPossibleLabels(int nodeId)

Returns the set of labels that this message passer supports

Parameters:

nodeId - The node whose labels is wanted

Returns:

the set of labels that this message passer supports

numEdges

int numEdges()

Returns the number of paths that messages should be passed down. In conjunction with the getEdge(int) method, all paths can be retrieved.

Returns:

the number of paths that messages can be passed through

numNodes

int numNodes()

Returns the number of nodes in the energy function.

Returns:

the number of nodes in the energy function

getEdge

Pair<java.lang.Integer,java.lang.Integer> getEdge(int i)

Returns the indices for the two endpoints in the specified path. The path ID should be 0-indexed and all paths from 0 through ( numEdges() - 1) should return a non-null value. All path IDs outside that range should throw an Exception.

Parameters:

i - The path ID (should be in [0 ... numEdges()) ).

Returns:

The two endpoints' IDs (to be used for #getUnaryCost(int) and #getPairwisePotential(int, int, Object, Object))

getUnaryPotential

double getUnaryPotential(int i,
                         LabelType label)

Returns the unary cost for node i having the input label. i must be a valid node id returned from getEdge(int). If not, an exception should be thrown.

Parameters:

i - The index of the node whose unary cost should be returned

label - The label that could be applied to the node

Returns:

The unary cost of node i being assigned the input label

getPairwisePotential

double getPairwisePotential(int edgeId,
                            LabelType ilabel,
                            LabelType jlabel)

Returns the pairwise cost of node i being assigned label_i and node j being assigned label_j. NOTE: i and j must be the two endpoints returned by getEdge(int) in the ordere specified by the returned pair (i = getFirst, j = getSecond). If not, an exception should be thrown.

Parameters:

edgeId - The id for the edge being requested

ilabel - The label being (possibly) assigned to node i

jlabel - The label being (possibly) assigned to node j

Returns:

the pairwise cost of node i being assigned label_i and node j being assigned label_j

getUnaryCost

double getUnaryCost(int i,
                    LabelType label)

This is the -log(getUnaryPotential(.)).

Parameters:

i -

label -

Returns:

getPairwiseCost

double getPairwiseCost(int edgeId,
                       LabelType ilabel,
                       LabelType jlabel)

This is the -log(getPairwisePotential(.)).

Parameters:

edgeId -

ilabel -

jlabel -

Returns: