com.planetj.taste.impl.neighborhood
Class NearestNUserNeighborhood

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

All Implemented Interfaces:

Refreshable, UserNeighborhood

public final class NearestNUserNeighborhood
extends java.lang.Object

Computes a neigbhorhood consisting of the nearest n Users to a given User. "Nearest" is defined by the given UserCorrelation.

Author:

Sean Owen

Constructor Summary

NearestNUserNeighborhood(int n, UserCorrelation userCorrelation, DataModel dataModel)

NearestNUserNeighborhood(int n, 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

NearestNUserNeighborhood

public NearestNUserNeighborhood(int n,
                                UserCorrelation userCorrelation,
                                DataModel dataModel)
                         throws TasteException

Parameters:

n - neighborhood size

userCorrelation - nearness metric

dataModel - data model

Throws:

java.lang.IllegalArgumentException - if n < 1, or userCorrelation or dataModel are null

TasteException

NearestNUserNeighborhood

public NearestNUserNeighborhood(int n,
                                UserCorrelation userCorrelation,
                                DataModel dataModel,
                                double samplingRate)
                         throws TasteException

Parameters:

n - neighborhood size

userCorrelation - nearness metric

dataModel - data model

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

Throws:

java.lang.IllegalArgumentException - if n < 1 or samplingRate is NaN or not in (0,1], or 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