org.lenskit.eval.traintest.metrics

Class LogDiscount

java.lang.Object

org.lenskit.eval.traintest.metrics.LogDiscount

All Implemented Interfaces:

Discount

public class LogDiscount
extends java.lang.Object
implements Discount

Logarithmic discounting. All ranks up through the log base have a discount of 1.

Constructor Summary

Constructors

Constructor and Description
LogDiscount(double base) Construct a log discount.

Method Summary

Modifier and Type	Method and Description
double	discount(int rank) Compute the discount for a rank.
boolean	equals(java.lang.Object o)
double	getLogBase() Get the log base from the discount.
int	hashCode()
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

LogDiscount

public LogDiscount(double base)

Construct a log discount.

Parameters:

base - The discount base.

Method Detail

getLogBase

public double getLogBase()

Get the log base from the discount.

Returns:

The discount’s log base.

discount

public double discount(int rank)

Description copied from interface: Discount

Compute the discount for a rank.

Specified by:

discount in interface Discount

Parameters:

rank - The rank (with the first item having rank 1).

Returns:

The discount. This discount will be multiplied by the value, so it should generally go towards 0 as the rank increases.

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object