com.planetj.taste.impl.neighborhood
Class ThresholdUserNeighborhood

java.lang.Object
  com.planetj.taste.impl.neighborhood.ThresholdUserNeighborhood

All Implemented Interfaces:

Refreshable, UserNeighborhood

public final class ThresholdUserNeighborhood
extends java.lang.Object

Computes a neigbhorhood consisting of all Users whose similarity to the given User meets or exceeds a certain threshold. Similartiy is defined by the given UserCorrelation.

Author:

Sean Owen

Constructor Summary

ThresholdUserNeighborhood(double threshold, UserCorrelation userCorrelation, DataModel dataModel)

ThresholdUserNeighborhood(double threshold, UserCorrelation userCorrelation, DataModel dataModel, double samplingRate)

Method Summary

java.util.Collection<User>	getUserNeighborhood(java.lang.Object userID)
void	refresh() Triggers "refresh" -- whatever that means -- of the implementation.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ThresholdUserNeighborhood

public ThresholdUserNeighborhood(double threshold,
                                 UserCorrelation userCorrelation,
                                 DataModel dataModel)
                          throws TasteException

Parameters:

threshold - similarity threshold

userCorrelation - similarity metric

dataModel - data model

Throws:

java.lang.IllegalArgumentException - if threshold is Double.NaN, or if samplingRate is not positive and less than or equal to 1.0, or if userCorrelation or dataModel are null

TasteException

ThresholdUserNeighborhood

public ThresholdUserNeighborhood(double threshold,
                                 UserCorrelation userCorrelation,
                                 DataModel dataModel,
                                 double samplingRate)
                          throws TasteException

Parameters:

threshold - similarity threshold

userCorrelation - similarity metric

dataModel - data model

samplingRate - percentage of users to consider when building neighborhood -- decrease to trade quality for performance

Throws:

java.lang.IllegalArgumentException - if threshold or samplingRate is Double.NaN, or if samplingRate is not positive and less than or equal to 1.0, or if userCorrelation or dataModel are null

TasteException

Since:

1.3

Method Detail

getUserNeighborhood

@NotNull
public java.util.Collection<User> getUserNeighborhood(java.lang.Object userID)
                                               throws TasteException

Parameters:

userID - ID of user for which a neighborhood will be computed

Returns:

Collection of Users in the neighborhood

Throws:

TasteException - if an error occurs while accessing data

toString

@NotNull
public java.lang.String toString()

Overrides:

toString in class java.lang.Object

refresh

public final void refresh()

Triggers "refresh" -- whatever that means -- of the implementation. The general contract is that any Refreshable should always leave itself in a consistent, operational state, and that the refresh atomically updates internal state from old to new.

Specified by:

refresh in interface Refreshable