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https://issues.apache.org/jira/browse/FLINK-1758?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14499846#comment-14499846
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ASF GitHub Bot commented on FLINK-1758:
---------------------------------------
Github user vasia commented on a diff in the pull request:
https://github.com/apache/flink/pull/576#discussion_r28594561
--- Diff: docs/gelly_guide.md ---
@@ -316,28 +327,49 @@ DataSet<Tuple2<Long, Long>> verticesWithSum =
graph.reduceOnNeighbors(
new SumValues(), EdgeDirection.IN);
// user-defined function to sum the neighbor values
-static final class SumValues implements NeighborsFunction<Long, Long,
Double, Tuple2<Long, Long>> {
-
- public Tuple2<Long, Long> iterateNeighbors(Iterable<Tuple3<Long,
Edge<Long, Double>,
- Vertex<Long, Long>>> neighbors) {
-
- long sum = 0;
- long vertexId = -1;
+static final class SumValues implements ReduceNeighborsFunction<Long,
Long, Double> {
- for (Tuple3<Long, Edge<Long, Double>, Vertex<Long, Long>>
neighbor : neighbors) {
- vertexId = neighbor.f0;
- sum += neighbor.f2.getValue();
- }
- return new Tuple2<Long, Long>(vertexId, sum);
- }
+ public Tuple3<Long, Edge<Long, Long>, Vertex<Long, Long>>
reduceNeighbors(Tuple3<Long, Edge<Long, Long>, Vertex<Long, Long>>
firstNeighbor,
+
Tuple3<Long, Edge<Long, Long>, Vertex<Long, Long>> secondNeighbor) {
+
+ long sum = firstNeighbor.f2.getValue() +
secondNeighbor.f2.getValue();
+ return new Tuple3<Long, Edge<Long, Long>, Vertex<Long,
Long>>(firstNeighbor.f0, firstNeighbor.f1,
+ new Vertex<Long, Long>(firstNeighbor.f0, sum));
+ }
}
{% endhighlight %}
<p class="text-center">
- <img alt="reduseOnNeighbors Example" width="70%"
src="img/gelly-reduceOnNeighbors.png"/>
+ <img alt="reduceOnNeighbors Example" width="70%"
src="img/gelly-reduceOnNeighbors.png"/>
--- End diff --
good catch :+1:
> Extend Gelly's neighborhood methods
> -----------------------------------
>
> Key: FLINK-1758
> URL: https://issues.apache.org/jira/browse/FLINK-1758
> Project: Flink
> Issue Type: Improvement
> Components: Gelly
> Affects Versions: 0.9
> Reporter: Vasia Kalavri
> Assignee: Andra Lungu
>
> Currently, the neighborhood methods only allow returning a single value per
> vertex. In many cases, it is desirable to return several or no value per
> vertex. This is the case in clustering coefficient computation,
> vertex-centric jaccard, algorithms where a vertex computes a value per edge
> or when a vertex computes a value only for some of its neighbors.
> This issue proposes to
> - change the current reduceOnEdges/reduceOnNeighbors methods to use
> combinable reduce operations where possible
> - provide groupReduce-versions, which will use a Collector and allow
> returning none or more values per vertex.
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