eu.stratosphere.example.java.record.kmeans.udfs

Class FindNearestCenter

java.lang.Object

eu.stratosphere.api.common.functions.AbstractFunction

eu.stratosphere.api.java.record.functions.ReduceFunction

eu.stratosphere.example.java.record.kmeans.udfs.FindNearestCenter

All Implemented Interfaces:

Function, GenericReducer<Record,Record>, Serializable

public class FindNearestCenter
extends ReduceFunction
implements Serializable

Reduce PACT determines the closes cluster center for a data point. This is a minimum aggregation. Hence, a Combiner can be easily implemented.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
FindNearestCenter()

Method Summary

Methods

Modifier and Type	Method and Description
void	combine(Iterator<Record> pointsWithDistance, Collector<Record> out) Computes a minimum aggregation on the distance of a data point to cluster centers.
void	reduce(Iterator<Record> pointsWithDistance, Collector<Record> out) Computes a minimum aggregation on the distance of a data point to cluster centers.

Methods inherited from class eu.stratosphere.api.common.functions.AbstractFunction

close, getIterationRuntimeContext, getRuntimeContext, open, setRuntimeContext

Methods inherited from class java.lang.Object

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

Methods inherited from interface eu.stratosphere.api.common.functions.Function

close, getRuntimeContext, open, setRuntimeContext

Constructor Detail

FindNearestCenter

public FindNearestCenter()

Method Detail

reduce

public void reduce(Iterator<Record> pointsWithDistance,
          Collector<Record> out)

Computes a minimum aggregation on the distance of a data point to cluster centers. Output Format: 0: centerID 1: pointVector 2: constant(1) (to enable combinable average computation in the following reducer)

Specified by:

reduce in interface GenericReducer<Record,Record>

Specified by:

reduce in class ReduceFunction

combine

public void combine(Iterator<Record> pointsWithDistance,
           Collector<Record> out)

Computes a minimum aggregation on the distance of a data point to cluster centers.

Specified by:

combine in interface GenericReducer<Record,Record>

Overrides:

combine in class ReduceFunction