Gelly CommunityDetection in scala example

[Trevor Grant]

The following example in the scala shell worked as expected:

import org.apache.flink.graph.library.LabelPropagation

val verticesWithCommunity = graph.run(new LabelPropagation(30))

// print the result

verticesWithCommunity.print

I tried to extend the example to use CommunityDetection:

import org.apache.flink.graph.library.CommunityDetection

val verticesWithCommunity = graph.run(new CommunityDetection(30, 0.5))

// print the result

verticesWithCommunity.print

And meant the following error:

error: polymorphic expression cannot be instantiated to expected type;

found : [K]org.apache.flink.graph.library.CommunityDetection[K]

required: org.apache.flink.graph.GraphAlgorithm[Long,String,Double,?]

val verticesWithCommunity = graph.run(new CommunityDetection(30, 0.5))

^

I haven't been able to come up with a hack to make this work. Any advice/bug?

I invtestigated the code base a little, seems to be an issue with what Graph.run expects to see vs. what LabelPropagation returns vs. what CommunityDetection returns.

[Suneel Marthi]

Recall facing a similar issue while trying to contribute a gelly-scala example to flink-training.

See https://github.com/dataArtisans/flink-training-exercises/blob/master/src/main/scala/com/dataartisans/flinktraining/exercises/gelly_scala/PageRankWithEdgeWeights.scala

On Wed, Apr 27, 2016 at 11:35 AM, Trevor Grant <[hidden email]> wrote:

The following example in the scala shell worked as expected:

import org.apache.flink.graph.library.LabelPropagation

val verticesWithCommunity = graph.run(new LabelPropagation(30))

// print the result

verticesWithCommunity.print

I tried to extend the example to use CommunityDetection:

import org.apache.flink.graph.library.CommunityDetection

val verticesWithCommunity = graph.run(new CommunityDetection(30, 0.5))

// print the result

verticesWithCommunity.print

And meant the following error:

error: polymorphic expression cannot be instantiated to expected type;

found : [K]org.apache.flink.graph.library.CommunityDetection[K]

required: org.apache.flink.graph.GraphAlgorithm[Long,String,Double,?]

val verticesWithCommunity = graph.run(new CommunityDetection(30, 0.5))

^

I haven't been able to come up with a hack to make this work. Any advice/bug?

I invtestigated the code base a little, seems to be an issue with what Graph.run expects to see vs. what LabelPropagation returns vs. what CommunityDetection returns.

Trevor Grant

Data Scientist

https://github.com/rawkintrevo

http://stackexchange.com/users/3002022/rawkintrevo

http://trevorgrant.org

"Fortunate is he, who is able to know the causes of things."  -Virgil

[Vasiliki Kalavri]

Hi Trevor,

note that the community detection algorithm returns a new graph where the vertex values correspond to the computed communities. Also, note that the current implementation expects a graph with java.lang.Long vertex values and java.lang.Double edge values.

The following should work:

import java.lang.Long

import java.lang.Double

...

val graph: Graph[Long, Long, Double] = ... // create your graph

val resultGraph = graph.run(new CommunityDetection[Long](30, 0.5))

resultGraph.getVertices.print()

Cheers,

-Vasia.

On 27 April 2016 at 17:41, Suneel Marthi <[hidden email]> wrote:

Recall facing a similar issue while trying to contribute a gelly-scala example to flink-training.

See https://github.com/dataArtisans/flink-training-exercises/blob/master/src/main/scala/com/dataartisans/flinktraining/exercises/gelly_scala/PageRankWithEdgeWeights.scala

On Wed, Apr 27, 2016 at 11:35 AM, Trevor Grant <[hidden email]> wrote:

The following example in the scala shell worked as expected:

import org.apache.flink.graph.library.LabelPropagation

val verticesWithCommunity = graph.run(new LabelPropagation(30))

// print the result

verticesWithCommunity.print

I tried to extend the example to use CommunityDetection:

import org.apache.flink.graph.library.CommunityDetection

val verticesWithCommunity = graph.run(new CommunityDetection(30, 0.5))

// print the result

verticesWithCommunity.print

And meant the following error:

error: polymorphic expression cannot be instantiated to expected type;

found : [K]org.apache.flink.graph.library.CommunityDetection[K]

required: org.apache.flink.graph.GraphAlgorithm[Long,String,Double,?]

val verticesWithCommunity = graph.run(new CommunityDetection(30, 0.5))

^

I haven't been able to come up with a hack to make this work. Any advice/bug?

I invtestigated the code base a little, seems to be an issue with what Graph.run expects to see vs. what LabelPropagation returns vs. what CommunityDetection returns.

Trevor Grant

Data Scientist

https://github.com/rawkintrevo

http://stackexchange.com/users/3002022/rawkintrevo

http://trevorgrant.org

"Fortunate is he, who is able to know the causes of things."  -Virgil