org.lenskit.transform.quantize

Interface Quantizer

All Known Implementing Classes:

PreferenceDomainQuantizer, ValueArrayQuantizer

@DefaultProvider(value=PreferenceDomainQuantizer.AutoProvider.class)
public interface Quantizer

Quantize real values into discrete values. Used to do things like map floating point ratings or predictions to discrete rating values. By default, if there is a preference domain available, a PreferenceDomainQuantizer will be used to implement this interface.

Method Summary

Modifier and Type	Method and Description
int	getCount() Get the number of discrete values the output can take.
double	getIndexValue(int i) Get the value corresponding to a quantized value, based on the index into the list of possible values.
org.apache.commons.math3.linear.RealVector	getValues() Get the possible values into which this quantizer will map input values.
int	index(double val) Convert a value into a discrete, quantized value.
double	quantize(double val) Convert a value into a quantized value, returning the quantized value.

Method Detail

getValues

org.apache.commons.math3.linear.RealVector getValues()

Get the possible values into which this quantizer will map input values. These are the values corresponding to each “bin” into which the quantizer will put values.

Returns:

The values of the discrete bins.

getIndexValue

double getIndexValue(int i)

Get the value corresponding to a quantized value, based on the index into the list of possible values.

Parameters:

i - The quantized value number, in the range [0,n) where n is the number of possible discrete values (see getCount()).

Returns:

The value corresponding to quantum i.

Throws:

java.lang.IllegalArgumentException - if i is an invalid discrete value.

getCount

int getCount()

Get the number of discrete values the output can take.

Returns:

The number of possible discrete values.

index

int index(double val)

Convert a value into a discrete, quantized value.

Parameters:

val - A value to quantize.

Returns:

The index of the discrete value to which val is mapped.

quantize

double quantize(double val)

Convert a value into a quantized value, returning the quantized value.

Parameters:

val - A value to quantize.

Returns:

The quantized value.