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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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package org.apache.flink.test.iterative.aggregators;
import java.util.ArrayList;
import java.util.List;
import org.apache.flink.api.common.aggregators.ConvergenceCriterion;
import org.apache.flink.api.common.aggregators.LongSumAggregator;
import org.apache.flink.api.common.functions.RichFlatMapFunction;
import org.apache.flink.api.common.functions.RichGroupReduceFunction;
import org.apache.flink.api.common.functions.RichJoinFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.test.util.JavaProgramTestBase;
import org.apache.flink.types.LongValue;
import org.apache.flink.util.Collector;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.operators.IterativeDataSet;
/**
*
* Connected Components test case that uses a parametrizable convergence criterion
*
*/
public class ConnectedComponentsWithParametrizableConvergenceITCase extends JavaProgramTestBase {
private static final int MAX_ITERATIONS = 10;
private static final int DOP = 1;
protected static List<Tuple2<Long, Long>> verticesInput = new ArrayList<Tuple2<Long, Long>>();
protected static List<Tuple2<Long, Long>> edgesInput = new ArrayList<Tuple2<Long, Long>>();
private String resultPath;
private String expectedResult;
@Override
protected void preSubmit() throws Exception {
// vertices input
verticesInput.clear();
verticesInput.add(new Tuple2<Long, Long>(1l,1l));
verticesInput.add(new Tuple2<Long, Long>(2l,2l));
verticesInput.add(new Tuple2<Long, Long>(3l,3l));
verticesInput.add(new Tuple2<Long, Long>(4l,4l));
verticesInput.add(new Tuple2<Long, Long>(5l,5l));
verticesInput.add(new Tuple2<Long, Long>(6l,6l));
verticesInput.add(new Tuple2<Long, Long>(7l,7l));
verticesInput.add(new Tuple2<Long, Long>(8l,8l));
verticesInput.add(new Tuple2<Long, Long>(9l,9l));
// vertices input
edgesInput.clear();
edgesInput.add(new Tuple2<Long, Long>(1l,2l));
edgesInput.add(new Tuple2<Long, Long>(1l,3l));
edgesInput.add(new Tuple2<Long, Long>(2l,3l));
edgesInput.add(new Tuple2<Long, Long>(2l,4l));
edgesInput.add(new Tuple2<Long, Long>(2l,1l));
edgesInput.add(new Tuple2<Long, Long>(3l,1l));
edgesInput.add(new Tuple2<Long, Long>(3l,2l));
edgesInput.add(new Tuple2<Long, Long>(4l,2l));
edgesInput.add(new Tuple2<Long, Long>(4l,6l));
edgesInput.add(new Tuple2<Long, Long>(5l,6l));
edgesInput.add(new Tuple2<Long, Long>(6l,4l));
edgesInput.add(new Tuple2<Long, Long>(6l,5l));
edgesInput.add(new Tuple2<Long, Long>(7l,8l));
edgesInput.add(new Tuple2<Long, Long>(7l,9l));
edgesInput.add(new Tuple2<Long, Long>(8l,7l));
edgesInput.add(new Tuple2<Long, Long>(8l,9l));
edgesInput.add(new Tuple2<Long, Long>(9l,7l));
edgesInput.add(new Tuple2<Long, Long>(9l,8l));
resultPath = getTempDirPath("result");
expectedResult = "(1,1)\n" + "(2,1)\n" + "(3,1)\n" + "(4,1)\n" +
"(5,2)\n" + "(6,1)\n" + "(7,7)\n" + "(8,7)\n" + "(9,7)\n";
}
@Override
protected void testProgram() throws Exception {
ConnectedComponentsWithConvergenceProgram.runProgram(resultPath);
}
@Override
protected void postSubmit() throws Exception {
compareResultsByLinesInMemory(expectedResult, resultPath);
}
private static class ConnectedComponentsWithConvergenceProgram {
private static final String UPDATED_ELEMENTS = "updated.elements.aggr";
private static final long convergence_threshold = 3; // the iteration stops if less than this number os elements change value
public static String runProgram(String resultPath) throws Exception {
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
env.setDegreeOfParallelism(DOP);
DataSet<Tuple2<Long, Long>> initialSolutionSet = env.fromCollection(verticesInput);
DataSet<Tuple2<Long, Long>> edges = env.fromCollection(edgesInput);
IterativeDataSet<Tuple2<Long, Long>> iteration =
initialSolutionSet.iterate(MAX_ITERATIONS);
// register the convergence criterion
iteration.registerAggregationConvergenceCriterion(UPDATED_ELEMENTS,
new LongSumAggregator(), new UpdatedElementsConvergenceCriterion(convergence_threshold));
DataSet<Tuple2<Long, Long>> verticesWithNewComponents = iteration.join(edges).where(0).equalTo(0)
.with(new NeighborWithComponentIDJoin())
.groupBy(0).reduceGroup(new MinimumReduce());
DataSet<Tuple2<Long, Long>> updatedComponentId =
verticesWithNewComponents.join(iteration).where(0).equalTo(0)
.flatMap(new MinimumIdFilter());
iteration.closeWith(updatedComponentId).writeAsText(resultPath);
env.execute();
return resultPath;
}
}
public static final class NeighborWithComponentIDJoin extends RichJoinFunction<Tuple2<Long, Long>, Tuple2<Long, Long>, Tuple2<Long, Long>> {
private static final long serialVersionUID = 1L;
@Override
public Tuple2<Long, Long> join(Tuple2<Long, Long> vertexWithCompId,
Tuple2<Long, Long> edge) throws Exception {
vertexWithCompId.setField(edge.f1, 0);
return vertexWithCompId;
}
}
public static final class MinimumReduce extends RichGroupReduceFunction<Tuple2<Long, Long>, Tuple2<Long, Long>> {
private static final long serialVersionUID = 1L;
final Tuple2<Long, Long> resultVertex = new Tuple2<Long, Long>();
@Override
public void reduce(Iterable<Tuple2<Long, Long>> values, Collector<Tuple2<Long, Long>> out) {
Long vertexId = 0L;
Long minimumCompId = Long.MAX_VALUE;
for (Tuple2<Long, Long> value: values) {
vertexId = value.f0;
Long candidateCompId = value.f1;
if (candidateCompId < minimumCompId) {
minimumCompId = candidateCompId;
}
}
resultVertex.f0 = vertexId;
resultVertex.f1 = minimumCompId;
out.collect(resultVertex);
}
}
@SuppressWarnings("serial")
public static final class MinimumIdFilter extends RichFlatMapFunction<Tuple2<Tuple2<Long, Long>, Tuple2<Long, Long>>, Tuple2<Long, Long>> {
private static LongSumAggregator aggr;
@Override
public void open(Configuration conf) {
aggr = getIterationRuntimeContext().getIterationAggregator(
ConnectedComponentsWithConvergenceProgram.UPDATED_ELEMENTS);
}
@Override
public void flatMap(
Tuple2<Tuple2<Long, Long>, Tuple2<Long, Long>> vertexWithNewAndOldId,
Collector<Tuple2<Long, Long>> out) throws Exception {
if (vertexWithNewAndOldId.f0.f1 < vertexWithNewAndOldId.f1.f1) {
out.collect(vertexWithNewAndOldId.f0);
aggr.aggregate(1l);
} else {
out.collect(vertexWithNewAndOldId.f1);
}
}
}
// A Convergence Criterion with one parameter
@SuppressWarnings("serial")
public static final class UpdatedElementsConvergenceCriterion implements ConvergenceCriterion<LongValue> {
private long threshold;
public UpdatedElementsConvergenceCriterion(long u_threshold) {
this.threshold = u_threshold;
}
public long getThreshold() {
return this.threshold;
}
@Override
public boolean isConverged(int iteration, LongValue value) {
return value.getValue() < this.threshold;
}
}
}