Cosine Similarity

[Rodrigo Lacerda]

It´s possible to calculate the cosine similarity directly with gremlin?

Cosine similarity is the cosine of the angle between two n-dimensional vectors in an n-dimensional space. It is the dot product of the two vectors divided by the product of the two vectors’ lengths (or magnitudes). For two vectors A and B in an n-dimensional space:

I saw a link with Neo4j making this calculation .

The link is : http://www.neo4j.org/graphgist?8173017

Tkhs!!

[Daniel Kuppitz]

The queries from the Neo4j Gist converted to Gremlin:

https://gist.github.com/dkuppitz/79e0b009f0c9ae87db5a

Cheers,

Daniel

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[Stephen Mallette]

Very cool, daniel....I started messing with this earlier today for fun but realized it was going to take more than a few lines of gremlin to give a complete answer.  

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[Daniel Kuppitz]

Forgot to mention: You'll need the current master in order to make that Gist work.

Cheers,

Daniel

[Rodrigo Lacerda]

Wow, perfect!

I'll stay the whole weekend studying these queries !

Now another doubt in a matter of performance , is it better to do this calculation directly with gremlin or is it better to do it another way , eg using Python.

Anyway I will have to go through all the data.

any idea?

thank you!

[Russell Jurney]

Wow, that is complex.

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[Rodrigo Lacerda]

Hello Daniel!!

I need a little help!

I updated my titan to version 1.0.0, and the query similarity calculation is not working.

I looked in and saw no documentation found change that could generate the error.

Can you help me?

905932 [gremlin-server-exec-6] WARN  org.apache.tinkerpop.gremlin.server.op.AbstractEvalOpProcessor  - Exception processing a script on request [RequestMessage{, requestId=ead79fca-c092-49ab-9e14-afdf6c297afd, op='eval', processor='', args={gremlin= 

g.V().match(

  __.as("p1").outE("rated").as("r1"),

  __.as("r1").inV().as("m"),

  __.as("m").inE("rated").as("r2"),

  __.as("r2").outV().as("p2")

).where("p1", neq("p2")).

  group().by(select("p1","p2")).

          by(select("r1","r2").by("rating")).unfold().as("kv").

  mapKeys().addOutE("p1", "similarity", "p2").as("e").

  sideEffect {

    def r = it.path().get("kv").getValue()

    def xyDotProduct = r.collect {it.r1*it.r2}.sum()

    def xLength = Math.sqrt(r.collect {it.r1*it.r1}.sum())

    def yLength = Math.sqrt(r.collect {it.r2*it.r2}.sum())

    def similarity = xyDotProduct / (xLength * yLength)

    it.get().property("similarity", similarity)

  }.iterate()}}].

java.lang.ClassCastException: java.util.HashMap$Node cannot be cast to java.util.Map

at org.apache.tinkerpop.gremlin.process.traversal.step.map.MapKeysStep.flatMap(MapKeysStep.java:41)

at org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:47)

at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:140)

at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:54)

at org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:46)

at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:140)

at org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:54)

at org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.SideEffectStep.processNextStart(SideEffectStep.java:38)

at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.next(AbstractStep.java:126)

at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.next(AbstractStep.java:37)

at org.apache.tinkerpop.gremlin.process.traversal.Traversal.iterate(Traversal.java:166)

at org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal.iterate(GraphTraversal.java:1074)

at org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal$Admin.iterate(GraphTraversal.java:167)

at org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.DefaultGraphTraversal.iterate(DefaultGraphTraversal.java:45)

at org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversal$Admin$iterate.call(Unknown Source)

at Script2.run(Script2.groovy:8)

at org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine.eval(GremlinGroovyScriptEngine.java:525)

at org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine.eval(GremlinGroovyScriptEngine.java:365)

at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:233)

at org.apache.tinkerpop.gremlin.groovy.engine.ScriptEngines.eval(ScriptEngines.java:96)

at org.apache.tinkerpop.gremlin.groovy.engine.GremlinExecutor.lambda$eval$22(GremlinExecutor.java:244)

at java.util.concurrent.FutureTask.run(FutureTask.java:266)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

at java.lang.Thread.run(Thread.java:745)

Thank you!

Em sexta-feira, 24 de julho de 2015 14:24:53 UTC-3, Daniel Kuppitz escreveu:

[Daniel Kuppitz]

Hi Rodrigo,

we somehow lost some code in the 3.0 development and didn't even notice it until now. Consider it to be a bug.

However 3.0 is closed and 3.1 no longer has mapKeys(). Hence it will be "fixed" in the next Titan release where you will use select(keys) instead of mapKeys().

Sorry for that, but there's really not much we can do about that at this point.

Cheers,

Daniel

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