/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
* an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
* specific language governing permissions and limitations under the License.
**********************************************************************************************************************/
package eu.stratosphere.test.recordJobs.kmeans.udfs;
import java.io.Serializable;
import java.util.Collection;
import eu.stratosphere.api.java.record.functions.FunctionAnnotation.ConstantFieldsFirst;
import eu.stratosphere.api.java.record.functions.MapFunction;
import eu.stratosphere.configuration.Configuration;
import eu.stratosphere.types.DoubleValue;
import eu.stratosphere.types.IntValue;
import eu.stratosphere.types.Record;
import eu.stratosphere.util.Collector;
/**
* Cross PACT computes the distance of all data points to all cluster
* centers.
*/
@ConstantFieldsFirst({0,1})
public class ComputeDistanceParameterized extends MapFunction implements Serializable {
private static final long serialVersionUID = 1L;
private final DoubleValue distance = new DoubleValue();
private Collection<Record> clusterCenters;
@Override
public void open(Configuration parameters) throws Exception {
this.clusterCenters = this.getRuntimeContext().getBroadcastVariable("centers");
}
/**
* Computes the distance of one data point to one cluster center.
*
* Output Format:
* 0: pointID
* 1: pointVector
* 2: clusterID
* 3: distance
*/
@Override
public void map(Record dataPointRecord, Collector<Record> out) {
CoordVector dataPoint = dataPointRecord.getField(1, CoordVector.class);
for (Record clusterCenterRecord : this.clusterCenters) {
IntValue clusterCenterId = clusterCenterRecord.getField(0, IntValue.class);
CoordVector clusterPoint = clusterCenterRecord.getField(1, CoordVector.class);
this.distance.setValue(dataPoint.computeEuclidianDistance(clusterPoint));
// add cluster center id and distance to the data point record
dataPointRecord.setField(2, clusterCenterId);
dataPointRecord.setField(3, this.distance);
out.collect(dataPointRecord);
}
}
}