flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From balidani <...@git.apache.org>
Subject [GitHub] flink pull request: [FLINK-1514][Gelly] Add a Gather-Sum-Apply ite...
Date Wed, 25 Feb 2015 23:39:13 GMT
Github user balidani commented on a diff in the pull request:

    https://github.com/apache/flink/pull/408#discussion_r25391476
  
    --- Diff: flink-staging/flink-gelly/src/main/java/org/apache/flink/graph/example/GSASingleSourceShortestPathsExample.java
---
    @@ -0,0 +1,216 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you 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 org.apache.flink.graph.example;
    +
    +import org.apache.flink.api.common.ProgramDescription;
    +import org.apache.flink.api.common.functions.MapFunction;
    +import org.apache.flink.api.java.DataSet;
    +import org.apache.flink.api.java.ExecutionEnvironment;
    +import org.apache.flink.api.java.tuple.Tuple2;
    +import org.apache.flink.api.java.tuple.Tuple3;
    +import org.apache.flink.graph.Edge;
    +import org.apache.flink.graph.Graph;
    +import org.apache.flink.graph.Vertex;
    +import org.apache.flink.graph.example.utils.ExampleUtils;
    +import org.apache.flink.graph.gsa.ApplyFunction;
    +import org.apache.flink.graph.gsa.GatherFunction;
    +import org.apache.flink.graph.gsa.GatherSumApplyIteration;
    +import org.apache.flink.graph.gsa.SumFunction;
    +import org.apache.flink.graph.gsa.Triplet;
    +
    +import java.io.Serializable;
    +
    +/**
    + * This is an implementation of the Single Source Shortest Paths algorithm, using a gather-sum-apply
iteration
    + */
    +public class GSASingleSourceShortestPathsExample implements ProgramDescription {
    +
    +	// --------------------------------------------------------------------------------------------
    +	//  Program
    +	// --------------------------------------------------------------------------------------------
    +
    +	public static void main(String[] args) throws Exception {
    +
    +		if(!parseParameters(args)) {
    +			return;
    +		}
    +
    +		ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
    +
    +		DataSet<Vertex<Long, Double>> vertices = getVertexDataSet(env);
    +		DataSet<Edge<Long, Double>> edges = getEdgeDataSet(env);
    +
    +		Graph<Long, Double, Double> graph = Graph.fromDataSet(vertices, edges, env);
    +
    +		// The path from src to trg through edge e costs src + e
    +		// If the target's distance is 0 (the target is the actual source), return 0 instead
    +		GatherFunction<Double, Double, Double> gather = new SingleSourceShortestPathGather();
    +
    +		// Return the smaller path length to minimize distance
    +		SumFunction<Double, Double, Double> sum = new SingleSourceShortestPathSum();
    +
    +		// Iterate as long as the distance is updated
    +		ApplyFunction<Double, Double, Double> apply = new SingleSourceShortestPathApply();
    +
    +		// Execute the GSA iteration
    +		GatherSumApplyIteration<Long, Double, Double, Double> iteration = graph.createGatherSumApplyIteration(
    +				gather, sum, apply, maxIterations);
    +		Graph<Long, Double, Double> result = graph.mapVertices(new InitVerticesMapper<Long>(srcVertexId))
    +				.runGatherSumApplyIteration(iteration);
    +
    +		// Extract the vertices as the result
    +		DataSet<Vertex<Long, Double>> singleSourceShortestPaths = result.getVertices();
    +
    +		// emit result
    +		if(fileOutput) {
    +			singleSourceShortestPaths.writeAsCsv(outputPath, "\n", " ");
    +		} else {
    +			singleSourceShortestPaths.print();
    +		}
    +
    +		env.execute("GSA Single Source Shortest Paths Example");
    +	}
    +
    +	public static final class InitVerticesMapper<K extends Comparable<K> &
Serializable>
    +			implements MapFunction<Vertex<K, Double>, Double> {
    +
    +		private K srcVertexId;
    +
    +		public InitVerticesMapper(K srcId) {
    +			this.srcVertexId = srcId;
    +		}
    +
    +		public Double map(Vertex<K, Double> value) {
    +			if (value.f0.equals(srcVertexId)) {
    +				return 0.0;
    +			} else {
    +				return Double.POSITIVE_INFINITY;
    +			}
    +		}
    +	}
    +
    +	// --------------------------------------------------------------------------------------------
    +	//  Single Source Shortest Path UDFs
    +	// --------------------------------------------------------------------------------------------
    +
    +	private static final class SingleSourceShortestPathGather
    +			extends GatherFunction<Double, Double, Double> {
    +		@Override
    +		public Double gather(Triplet<Double, Double> triplet) {
    +			return triplet.getSource() + triplet.getEdge();
    +		}
    +	};
    +
    +	private static final class SingleSourceShortestPathSum
    +			extends SumFunction<Double, Double, Double> {
    +		@Override
    +		public Double sum(Double arg0, Double arg1) {
    +			return Math.min(arg0, arg1);
    +		}
    +	};
    +
    +	private static final class SingleSourceShortestPathApply
    +			extends ApplyFunction<Double, Double, Double> {
    +		@Override
    +		public void apply(Double summed, Double target) {
    --- End diff --
    
    Should this be done in `GatherSumApplyIteration` and the GGC example as well?


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message