[Neo4j] Gremlin steps in JavaDoc.
Hi, For those using Gremlin and wanting a complete list of all provided steps and their various overloadings, please see: http://tinkerpop.com/maven2/com/tinkerpop/gremlin/gremlin-java/1.4/api/com/tinkerpop/gremlin/java/GremlinPipeline.html Note that this is for Gremlin 1.4 (released 2 days ago). Any method that takes a PipeFunction in Gremlin Groovy is a closure and in Gremlin Scala is an anonymous function. Finally, apologies for the lack of commenting -- JavaDoc didn't inherit from respective interfaces as I expected it to. Hope that is useful, Marko. http://markorodriguez.com ___ NOTICE: THIS MAILING LIST IS BEING SWITCHED TO GOOGLE GROUPS, please register and consider posting at https://groups.google.com/forum/#!forum/neo4j Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Neo4jClient - Query optmised
Nice!
BTW: Great work on the Neo4j .Net Client.
Marko.
http://markorodriguez.com
On Dec 7, 2011, at 9:14 PM, Romiko Derbynew wrote:
Finally thanks to Peter and Marko, the .Net Neo4jClient code has been
optimised to use short hand version of in('') and out('').
ChangeSet is http://hg.readify.net/neo4jclient/changeset/91ef447a9053
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[Neo4j] TinkerPop Stack Release
Hello, Yesterday TinkerPop did another stable release. This release depends on Neo4j 1.5. Here are the notes for those that are interested: New homepage design: http://tinkerpop.com Blueprints 1.1 (Blueberry): https://github.com/tinkerpop/blueprints/wiki/Release-Notes Pipes 0.9 (Sink): https://github.com/tinkerpop/pipes/wiki/Release-Notes Gremlin 1.4 (Ain't No Thing But a Chicken Wing): https://github.com/tinkerpop/gremlin/wiki/Release-Notes Frames 0.6 (Truss): https://github.com/tinkerpop/frames/wiki/Release-Notes Rexster 0.7 (Brian) https://github.com/tinkerpop/rexster/wiki/Release-Notes Rexster-Kibbles 0.7 (http://rexster-kibbles.tinkerpop.com) PLEASE READ THE FOLLOWING NOTES: 1. Be aware that old rexster.xml files will not work with Rexster 0.7. The tag graph-file has been changed to graph-location. 2. Realize that when you download Gremlin, there are two versions to pick from --- Groovy and Scala. - Gremlin Groovy is what everyone is familiar with. - Gremlin Scala is making its debut as an experiment in exposing the Gremlin style in other JVM languages besides Groovy. (thank you Zach Cox) - Gremlin Java exists (via Maven2 or raw .jar) for those wanting to do the Gremlin style in pure Java -or- add Gremlin to another JVM language. - See: https://github.com/tinkerpop/gremlin/wiki/JVM-Language-Implementations 3. Pipes no longer depends on Blueprints. All the graph specific pipes have been moved to Gremlin. Pipes is simply a generic data flow framework now. - depend on gremlin-java if you want to use Blueprints specific pipes. Enjoy!, Marko. http://markorodriguez.com ___ NOTICE: THIS MAILING LIST IS BEING SWITCHED TO GOOGLE GROUPS, please register and consider posting at https://groups.google.com/forum/#!forum/neo4j Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] println and Table Projections
Hi,
Peter brings up a good point. Its hard for us to parse complex queries and see
where Exceptions are happening. If you can isolate the problem via a simpler
traversal, that would be best for us -- and our little baby brains.
Also, note the following syntax optimizations for your traversal:
1. outE[[label:'HOSTS']].inV --- out('HOSTS')
2. Similarly, inE[[label:'X']].outV - in('X')
Using out() and in() is much more efficient (faster) and more concise. Unless
you plan to reason on the properties of an edge, then there is no reason to use
outE.inV style syntax as out will do the full vertex-to-vertex jump for you.
HTH,
Marko.
http://markorodriguez.com
On Dec 7, 2011, at 1:00 AM, Peter Neubauer wrote:
Mmh,
I was thinking on how to return the contents of the output stream, I
am not quite sure how to return that. What woudl be a good format for
you?
Also could you reduce this into a small testcase that I can work on?
Cheers,
/peter neubauer
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Skype peter.neubauer
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brew install neo4j neo4j start
heroku addons:add neo4j
On Wed, Dec 7, 2011 at 8:10 AM, Romiko Derbynew
romiko.derby...@readify.net wrote:
Hi,
I have this statement.
g.v('0').outE[[label:'HOSTS']].inV.filter{
it['Key'].equalsIgnoreCase('romikoagency')
}.inE[[label:'USER_BELONGS_TO']].outV.filter{
it['Username'].equalsIgnoreCase('romiko.derbynew')
}.ifThenElse{it.outE[[label:'USER_LINKED_TO_CENTRE']].inV.hasNext()}{it.outE[[label:'USER_LINKED_TO_CENTRE']].inV.Name}{println
${it} Unknown}.as('Centre')
I then take this query and do a table projection, however I get the
following error.
println java.lang.String cannot be cast to
com.tinkerpop.blueprints.pgm.Vertex
Is there a better way to do this then? I want to reduce our calls to the DB
for performance and finding it a bit tough wrapping everything into one
query. Currently the above query is split into two different queries.
Much appreciated.
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Re: [Neo4j] [Neo4j-User] Re: Gremlin Query - Help
Hi,
You can do nested ifThenElses. One way to think about things is not as big ol'
one-liners.
g.V.ifThenElse{ ifStatement } {
thenStatement
} {
elseStatement
}
With new lines, the embeddness then starts to look like plain ol' C-style
syntax.
Also note that in Gremlin 1.4 (releasing this week), the _() will not be needed
anymore for start objects. I learned how to solve that at SpringONE :).
Thanks,
Marko.
http://markorodriguez.com
On Dec 5, 2011, at 8:27 PM, Romiko Derbynew wrote:
Marko,
I am thinking of using this statement.
g.V.ifThenElse{it.out('hasCentre').filter{it == aCentre}.hasNext()}{}{println
${it} has center unknown}
to get nodes that DO NOT have a relationship, is this the best way to do it?
I guess so, if this is the case, I am now adding support to the .NET graph
client to support ifThenElse expressions. I am wondering though, as I am
designing the interface for it, can and ifThenElse have nested ifThenElse
expressions as well? I guess it and _() can be used within them?
Cheers
-Original Message-
From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org] On
Behalf Of Marko Rodriguez
Sent: Saturday, 3 December 2011 4:10 AM
To: Neo4j user discussions
Subject: Re: [Neo4j] Gremlin Query - Help
Hi,
Scenario 1:
I would like to get all Nodes that do not have a relationship to another
node. What is the best way to do this Gremlin?
Root = NodeA = NodeB
Root = NodeC
Output should be NodeC
I don't understand the problem.
Scenario 2:
Root = User - Centre
I would like to get all centres for userA, and then get all users who
are also linked to the same centres of the userA
userA.out('hasCentre').in('hasCentre').except([userA])
Scenario 3:
User = Centre
I would like to get all users that do not have a link to a Centre, and if
this is the case, do a projection that returns a fake centre with property
Unknown
g.V.ifThenElse{it.out('hasCentre').filter{it ==
aCentre}.hasNext()}{}{println ${it} has center unknown}
If you have an index of your Users, then its more efficient to hit that
index, then iterate through all vertices (g.V). E.g.
g.idx(T.v)[[type:'User']].ifThenElse
Scenario 4:
REFERRAL = PERSON
I would like to combine a query that gets all Referrals that are
linked to a person and project a table result (contains referrals and
person property values (this is easy to do) However, I then want to do a
SPLIT query, that gets referrals without the persons, and then MERGE both
back into the table projection? So table projecton might look like this.
I guess this is done with .table().it{}cap, but what I am not sure, is
how to do a split and merge in parallel and then get that merge projected
into the same table.
I don't quite understand your problem, but here is an example of splitting
and merging.
g.v(1).out('knows').copySplit(_().out('knows').name,
_().out('created').name).fairMerge
This will get all the people that v[1] knows and then generate two parallel
pipeline. Each friend of v[1] is copied to each of the 2 parallel pipelines.
One pipeline will get their friend's names and one will get their created
project's names. It will then merge those two parallel pipelines into a
single stream. You can do either fairMerge or exhaustMerge depending on the
merging algorithm you want. fairMerge is more memory efficient. I need to
write more about split/merge in the Gremlin documentation.
https://github.com/tinkerpop/gremlin/wiki/Split-Merge-Pattern -- will
work on it :)
HTH,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Aggregates inside copySplit()
Hi, I had to use Aggregate here, instead of Store(), else the Except does not work. The except() does work, but you have you understand how it works with respects to the semantics of aggregate() and store(). store = lazily store objects in the pipeline to some collection x aggregate = greedily aggregate objects in the pipeline to some collection x before moving onto the next step. So, except's excepted collection will be growing over time. However, with aggregate(), its collection is stable as it has already been greedily filled. Get it? I am not sure if I can call _() an identityPipe, any inspiration here? You mean between the two as()? Why not? Enjoy, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Anyone try out the PageRank function on Gremlin?
Hi, Anyone try out the PageRank function on Gremlin? https://github.com/tinkerpop/gremlin/wiki/Working-with-JUNG-Algorithms/0506c193f30abe0bc18d40d7a08c9257d9311b13 How does it perform with just under 100k nodes on a sparse graph (3000 relationship max, average of 100)? I've been doing my pagerank via the power method in rb-gsl and while it's fine for around 10k items, it's sucking all the memory on my server when trying to do 92k items. Blueprints ( https://github.com/tinkerpop/blueprints/wiki/JUNG-Ouplementation ) implements the JUNG graph interface and thus, makes any Blueprints-enabled graph database into a JUNG graph. Unfortunately, JUNG was engineered from the perspective of in-memory use. As such, you will be running into memory issues on very large graphs. For example, if you have a 1million+ vertex graph and you are running PageRank on it, then your eigenvector vector is 1million+ entries. JUNG isn't serializing this vector to disk for you---its doing it all in memory. And if you don't have the memory to support a 1million+ vector (i.e. MapVertex,Double), then, well So, in short, be wary of doing memory intensive algorithms with JUNG (i.e. understand the intermediate data structures generated from the various supported graph algorithms). For non-memory intensive algorithms like shortest path, it should meet your needs. Into the future, TinkerPop will be filling out Furnace (http://furnace.tinkerpop.com) and this package will provide memory conscious implementations of classic and non-classical graph algorithms. HTH, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Aggregates inside copySplit()
Hi Romiko, I am interested to learn more about the inner workings of Gremlin? I would too! :P This might help you out: http://markorodriguez.com/2011/08/03/on-the-nature-of-pipes/ Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Unique constraint and transaction over REST
Hey,
Matt: This isn't related to this thread, but I noticed you are from Scholar.ly.
I thought you might like this:
http://arxiv.org/abs/0905.1594
Go Canucks!,
Marko.
http://markorodriguez.com
On Dec 4, 2011, at 12:58 AM, Matt Luongo wrote:
Well, I had already started writing this before I saw your response- so, if
you do decide down the road that you care more about immediate performance
than keeping DRY... ;)
g.setMaxBufferSize(0) //turn on tx handlings
g.startTransaction()
found = g.idx('node_auto_index')[[name:'uni...@example.com']].count()
if (found == 0) {
//other custom create code could go here, and/or have vars passed
through json
results = g.addVertex([:])
} else {
results = g.idx('node_auto_index')[[name:'uni...@example.com
']].count().next()
}
g.stopTransaction(TransactionalGraph.Conclusion.SUCCESS)
g.setMaxBufferSize(1)
results
would be something like the Groovy you'd use.
I don't blame you for wanting to avoid the many choices available right now
- I'm already generating Javascript for traversal pruning and templating
Gremlin, all in the name of performance...
--
Matt Luongo
Co-Founder, Scholr.ly
On Sun, Dec 4, 2011 at 2:38 AM, dnagir dna...@gmail.com wrote:
Thanks Matt.
Yeah. I think the transaction API is in making. Would be great addition.
The server-side plugin will definitely work, but I personally prefer to
use one way of doing things. At least until I will start speaking neo4j
natively :)
Cheers,
Dmytrii
http://www.ApproachE.com
On 04/12/2011, at 6:35 PM, mhluongo [via Neo4j Community Discussions]
wrote:
I've run into this problem, and resorted to using the Gremlin/Groovy over
REST (via the server-included plugin).
There really isn't a way to transactionally express a conditional (or
get-or-create) like that over the vanilla REST API, though I'm sure it's
in
the works.
--
Matt Luongo
Co-Founder, Scholr.ly
On Thu, Dec 1, 2011 at 5:45 PM, dnagir [hidden email] wrote:
Hi,
I wonder what's the best way to do something similar to unique
constraints
in RDBMS.
For example, user registration requires that the user's email to be
unique.
Working over in Ruby over REST API, how do you achieve this?
I assume I need an auto-index on email property of User nodes. Then
query
it
to check the property.
But how can I make it transactional? So that I am sure that between
querying
and inserting the node, no similar has been inserted.
The transactional part better applies to reservation instead of user
creation. But you get the point.
Cheers.
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Re: [Neo4j] [Neo4j-User] Re: Unique constraint and transaction over REST
We have an alpha release coming up- would you be interested in seeing what we have? Oh would I! Golly gee. :P, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin/Groovy UNIQUE + Closure support
Hi, unique() is a Groovy construct, not a Gremlin construct. The Gremlin equivalent is uniqueObject(). And, in Gremlin 1.4, being released next week, its called dedup(). Gremlin constructs Pipelines in the backend (toString() an expression). If you drop out of pipeline construction by moving to a Groovy iterator method, then the pipeline is gone. https://github.com/tinkerpop/gremlin/wiki/Gremlin-Steps (note that this is being updated for Gremlin 1.4 and a few names have changed) (refer to the distribution /wiki for your versions steps) HTH, Marko. http://markorodriguez.com On Dec 2, 2011, at 9:13 PM, Romiko Derbynew wrote: Hi Guys, If I do a query with out.as(xyz)...out.unique()..out.tablecap I find that the table projections for the closure do not work and I lose all AS references. So to get closure support I do this Out.unique._().out..table The above sorts out the closure error, but then I lose my previous as projections, is there a way to ensure _() preserves all my previous pipes and placeholders? ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin/Groovy UNIQUE + Closure support
Hi, uniqueObject is in Gremlin 1.3 and below. The online docs are for Gremlin 1.4 and uniqueObject is now called dedup. To see the Gremlin 1.3 documentation, see the wiki/ directory of the distribution. HTH, Marko. http://markorodriguez.com On Dec 3, 2011 4:13 PM, Romiko Derbynew romiko.derby...@readify.net wrote: Hi Marko, Thank you very much for this information, is it possible that the documentation will include these gremlin methods, since on the Gremlin-Steps page, I failed to notice any mention of UniqueObject()? I am now updating the .NetClient asap :) Thank you once again! -Original Message- From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org]... ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin Query - Help
Hi,
Scenario 1:
I would like to get all Nodes that do not have a relationship to another
node. What is the best way to do this Gremlin?
Root = NodeA = NodeB
Root = NodeC
Output should be NodeC
I don't understand the problem.
Scenario 2:
Root = User - Centre
I would like to get all centres for userA, and then get all users who are
also linked to the same centres of the userA
userA.out('hasCentre').in('hasCentre').except([userA])
Scenario 3:
User = Centre
I would like to get all users that do not have a link to a Centre, and if
this is the case, do a projection that returns a fake centre with property
Unknown
g.V.ifThenElse{it.out('hasCentre').filter{it ==
aCentre}.hasNext()}{}{println ${it} has center unknown}
If you have an index of your Users, then its more efficient to hit that index,
then iterate through all vertices (g.V). E.g.
g.idx(T.v)[[type:'User']].ifThenElse
Scenario 4:
REFERRAL = PERSON
I would like to combine a query that gets all
Referrals that are linked to a person and project a table result (contains
referrals and person property values (this is easy to do)
However, I then want to do a SPLIT query, that gets referrals without the
persons, and then MERGE both back into the table projection? So table
projecton might look like this.
I guess this is done with .table().it{}cap, but what I am not sure, is
how to do a split and merge in parallel and then get that merge projected
into the same table.
I don't quite understand your problem, but here is an example of splitting and
merging.
g.v(1).out('knows').copySplit(_().out('knows').name,
_().out('created').name).fairMerge
This will get all the people that v[1] knows and then generate two parallel
pipeline. Each friend of v[1] is copied to each of the 2 parallel pipelines.
One pipeline will get their friend's names and one will get their created
project's names. It will then merge those two parallel pipelines into a single
stream. You can do either fairMerge or exhaustMerge depending on the merging
algorithm you want. fairMerge is more memory efficient. I need to write more
about split/merge in the Gremlin documentation.
https://github.com/tinkerpop/gremlin/wiki/Split-Merge-Pattern -- will
work on it :)
HTH,
Marko.
http://markorodriguez.com
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Re: [Neo4j] New Bug Logged - Gremlin 114
Hi,
Please put this into the Gremlin issue tracker.
https://github.com/tinkerpop/gremlin/issues
The table is not intended to be ordered with the location of the named as
steps. It was just not engineered that way. However, others have brought this
up. I suspect for Gremlin 1.5 (Gremlin 1.4 is being released soon), we can have
the behavior ordered.
Thanks Romiko and Peter,
Marko.
http://markorodriguez.com
On Nov 30, 2011, at 1:20 AM, Peter Neubauer wrote:
Thanks Romiko,
will look into it first time when I have time. How critical is it for you?
Cheers,
/peter neubauer
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On Wed, Nov 30, 2011 at 1:31 AM, Romiko Derbynew
romiko.derby...@readify.net wrote:
Hi,
New bugged logged at: https://github.com/neo4j/community/issues/114
Details below for others to peruse.
Gremlin Table Projections - Column Order Incorrect when using chained
.As('x').As('y')
EXPECTED Order: Createdy, ReferralGroup, ReferralId, ReferralData
When AS statements appear next to each other.
Consider A (WORKS - But not logical - have to reverse order when more than 1
AS statement is chained together right after each other for column array to
match):
{script:g.v(0).outE[[label:'HOSTS']].inV.filter{ it.Key == 'romikoagency'
}.inE[[label:'USER_BELONGS_TO']].outV.filter{ it.Username ==
'romiko.derbynew'
}.as('CreatedBy').outE[[label:'USER_LINKED_TO_PROGRAM']].inV.as('ReferralGroup').inE[[label:'HAS_SUGGESTED_PROGRAM']].outV.inE[[label:'REFERRAL_HAS_DECISIONS_SECTION']].outV.as('ReferralDate').as('ReferralId').table(new
Table()){it.Username}{it.Name}{it.UniqueId}{it.DateInitiatedUtc}.cap
}
notice: as('ReferralDate').as('ReferralId') and then notice the column order
below is opposite this: columns ReferralId, ReferralDate ]
Results
[ [ {
data : [ [ romiko.derbynew, Testa, 331, /Date(1322007153048+1100)/
], [ romiko.derbynew, Testa, 321, /Date(1322003375637+1100)/ ]],
columns : [ CreatedBy, ReferralGroup, ReferralId, ReferralDate ]
} ] ]
Consider B (Does not work - this is more LOGICAL from gremlin perspective
but is bugged, the Chained AS right after each other gets reversed in the
column array.)
{script:g.v(0).outE[[label:'HOSTS']].inV.filter{ it.Key == 'romikoagency'
}.inE[[label:'USER_BELONGS_TO']].outV.filter{ it.Username ==
'romiko.derbynew'
}.as('CreatedBy').outE[[label:'USER_LINKED_TO_PROGRAM']].inV.as('ReferralGroup').inE[[label:'HAS_SUGGESTED_PROGRAM']].outV.inE[[label:'REFERRAL_HAS_DECISIONS_SECTION']].outV.as('ReferralId').as('ReferralDate').table(new
Table()){it.Username}{it.Name}{it.UniqueId}{it.DateInitiatedUtc}.cap
}
Notice: .as('ReferralId').as('ReferralDate') and then the columns columns
ReferralDate, ReferralId ]
Results
[ [ {
data : [ [ romiko.derbynew, Testa, 331, /Date(1322007153048+1100)/
]],
columns : [ CreatedBy, ReferralGroup, ReferralDate, ReferralId ]
} ] ]
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Re: [Neo4j] New Bug Logged - Gremlin 114
Hi,
Actually, I know how to solve your problem. See below.
g.v(0).outE[[label:'HOSTS']].inV.filter{ it.Key == 'romikoagency'
}.inE[[label:'USER_BELONGS_TO']].outV.filter{ it.Username ==
'romiko.derbynew'
}.as('CreatedBy').outE[[label:'USER_LINKED_TO_PROGRAM']].inV.as('ReferralGroup').inE[[label:'HAS_SUGGESTED_PROGRAM']].outV.inE[[label:'REFERRAL_HAS_DECISIONS_SECTION']].outV.as('ReferralId').as('ReferralDate').table(new
Table()){it.Username}{it.Name}{it.UniqueId}{it.DateInitiatedUtc}.cap
You can not do two as() steps in a row. Do a toString() on your Pipeline
representation (e.g. cap.toString()). You will notice that your first as()
step is wrapped by the second one. To rectify this, insert an identity. For
example: as('ReferralId')._.as('ReferralDate').
Also, here are some optimizations to your expression that you might want to
consider. The first and the third are to make it easier on the eyes (and a bit
faster as well). The second is to make it faster.
outE[[label:'HOSTS']].inV ---turn into--
out('HOSTS')
filter{it.Key == 'romikoagency'}---turn into--
filter{it.getProperty('Key') == 'romikoagency'}
inE[[label:'USER_BELONGS_TO']].outV ---turn into--
in('USER_BELONGS_TO')
See: https://github.com/tinkerpop/gremlin/wiki/Gremlin-Groovy-Path-Optimizations
Enjoy!,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Securing scripting in the server
Hi Peter, Now, the question is if any of you has some experience tweaking the Java Security Manager to remove System.exit, File write permissions and other bad stuff from that code. Would love to see some examples of real-life securing JSR232 script engines. Or are there other mechanisms that work better than http://docs.oracle.com/javase/tutorial/essential/environment/security.htmlfor this type fo task? Remember you, me, and Josh worked on LinkedProcess a few years back ( http://xmpp.org/extensions/inbox/lop.html ). Given that any random user on the web could execute arbitrary code on another users machines, we had to solve the security hole problem. In our Java-based reference implementation LoPSideD, we tweaked the JVM such that arbitrary JSR223 code does not violate particulate security constraints. See: https://github.com/tinkerpop/tinkubator/blob/master/lopsided/lopsided-farm/sweden_countryside.properties and... https://github.com/tinkerpop/tinkubator/blob/master/lopsided/lopsided-farm/src/main/java/org/linkedprocess/farm/Farm.java#L189 ...the full codebase is in the Tinkubator at this location: https://github.com/tinkerpop/tinkubator/tree/master/lopsided In short, I believe that this was all set at the thread-level -- ?? -- however, Josh was the one who did the work on security so you might want to ask him. Hope that gives you some starting points, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin Script broken in 1.5 GA
Hi,
With Gremlin 1.3, filter{} is required. No shorthands. Thus, outE{} needs
to be outE.filter{}. Moreover, you can now do out(label) or outE(label).
HTH,
Marko.
http://markorodriguez.com
On Nov 19, 2011 10:25 AM, Haensel thehaen...@gmail.com wrote:
Don't know if this is a bug or a feature, so here we go:
In 1.5.M01 I used a gremlin query to find edges like that:
'{script:g.v(1).outE{it.label==\relationshipName\}}'
which now leads to a MissingMethod exception in 1.5 GA:
javax.script.ScriptException: groovy.lang.MissingMethodException: No
signature of method:
com.tinkerpop.blueprints.pgm.impls.neo4j.Neo4jVertex.outE() is applicable
for argument types: (Script16$_run_closure1) values:
[Script16$_run_closure1@7889fe65]\nPossible solutions:
outE([Ljava.lang.String;), out([Ljava.lang.String;), dump(),
use([Ljava.lang.Object;), both([Ljava.lang.String;),
inE([Ljava.lang.String;)
I got it working by changing the syntax to:
{script:g.v(1).outE(\relationshipName\)}
I don't know if this is intended or a bug so I wanted you guys to know about
it
Anyways, thanks for efforts ;)
Hannes
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Re: [Neo4j] Max flow using gremlin
Hi, has anyone implemented any of the max flow algorithms using gremlin? Most of the algorithms in my toolbox are flow-based algorithms. What in particular are you trying to do? Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Max flow using gremlin
Hey,
Perhaps the simplist way to explore flow is to simply get the paths between
source and sink and then calculate some function f over the path to determine
its flow. For example:
def f = { List path -
// some function over the path where every other element is an
edge (see traversal below)
}
source.outE.inV.loop(2){it.object.equals(sink)}.paths.each{
println(it + has a flow of + f(it))
}
This assumes you have a determined source and a determined sink and that there
are no cycles in your gas pipeline. If there are cycles, then you can tweak the
expression to make sure you break out of the loop when appropriate.
From this basic idea you can then tweak it to simulate decay over time/step or
implement random walks through the gasline if you are interested in sampling
or studying local eigenvectors in the pipeline.
Hope that provides you a good starting point.
Enjoy!,
Marko
http://markorodriguez.com
On Nov 18, 2011, at 1:20 PM, Alfredas Chmieliauskas wrote:
Hey Marko,
I'm modeling the european gas transport/pipeline network. I need to
have a good way to calculate maximum flow from source to sink and get
the nodes in the path .
Alfredas
On Fri, Nov 18, 2011 at 2:48 PM, Marko Rodriguez okramma...@gmail.com wrote:
Hi,
has anyone implemented any of the max flow algorithms using gremlin?
Most of the algorithms in my toolbox are flow-based algorithms. What in
particular are you trying to do?
Marko.
http://markorodriguez.com
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Re: [Neo4j] Max flow using gremlin
This seems to calculate the max flow (edges have capacity):
source.outE.inV.loop(2){!it.object.equals(sink)}.paths.each{flow =
it.capacity.min(); maxFlow += flow;
it.findAll{it.capacity}.each{it.capacity -= flow}};
I can't believe this is so short!
Thats the beauty of Gremlin. Once you get it, you can rip some very complex
traversals in just a few characters.
NOTES: For speed, make it.capacity - it.getProperty('capacity')
Some good notes here:
https://github.com/tinkerpop/gremlin/wiki/Gremlin-Groovy-Path-Optimizations
Glad we could help you with your problem.
Enjoy!,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Neo4j-Scala Wrapper 0.1.0 released
Hey,
It might be a little too soon to bring it up, but early December, we are
releasing Gremlin Scala in Gremlin 1.4 which will allow you to import Gremlin
into your Scala project (e.g. Neo4j-Scala Wrapper) and evaluate Gremlin queries
natively.
https://github.com/tinkerpop/gremlin/tree/master/gremlin-scala
For example, in Gremlin Scala:
g.v(1).out(knows).out(created).filter{v:Vertex =
v(name).equals(marko)}
This way Scala developers can use Gremlin-style traversing natively in their
Scala code.
See ya,
Marko.
http://markorodriguez.com
On Nov 17, 2011, at 5:21 AM, Christopher Schmidt wrote:
Peter, I think its not possible because [ and ] are reserved for Scalas
type declarations.
The String (fe. KNOWS) is implicitly converted
into DynamicRelationshipType.withName(KNOWS).
What would be possible to get something like this (which is actually just a
change of method names):
start - KNOWS - end
Regarding the Cypher language:
Its an interpreted language, so it is possible to define a completely free
syntax. In case of Scala, all we are doing has to be fit into the language
syntax, although it looks like a freely designed DSL. Cypher has some
similarities to SQL as a special query language. And to be honest, I think
using it programmatically will cause the same symtoms as SQL with respect
to runtime errors, type safety, abstraction etc.
Nevertheless, it would be interesting to create a nearly Cypher compilable
DSL, which includes type safety and transparent DAO or Case Class mapping.
Something like:
case class User(name:String)
val nodes = createNode(User(name1)) :: createNode(User(name2))
:: createNode(User(name3)) :: Nil
. . .
for (f - START nodes MATCH user-friend-follower WHERE follower.name =~
/S.*/ RETURN follower)
println(User Follower: + f.name)
This would be basically the same idea JPA tries with its criteria api. But
that will be hard work :-)
Christopher
On Wednesday, November 16, 2011, Peter Neubauer wrote:
Chstopher,
this looks really cool! I notice the similarity to the cypher syntax
in the ASCII art part of the notation. Do you think there is a chance
to make it even more similar to that so you could actually write
start -[:KNOWS]- intermediary - [KNOWS] - end
instead of
start -- KNOWS -- intermediary -- KNOWS -- end ? Would be
quite cool to be closely in line with
http://docs.neo4j.org/chunked/snapshot/cypher-query-lang.html, maybe
we could even use this for a modifying cypher in the future ...
Cheers,
/peter neubauer
GTalk: neubauer.peter
Skype peter.neubauer
Phone +46 704 106975
LinkedIn http://www.linkedin.com/in/neubauer
Twitter http://twitter.com/peterneubauer
http://www.neo4j.org - NOSQL for the Enterprise.
http://startupbootcamp.org/- Öresund - Innovation happens HERE.
On Wed, Nov 16, 2011 at 6:36 AM, Christopher Schmidt
fakod...@googlemail.com wrote:
Hi all,
I released version 0.1.0 of the Neo4j Scala Wrapper neo4j-scala (base is
neo4j-scala by jawher).
Main features are
- simple Traits for the wrapper itself, GraphDatabaseService provider,
index provider and batch insertion
- transaction wrapping:
withTx {...}
- natural usage of relations:
start -- KNOWS -- intermediary -- KNOWS -- end
- setting and getting properties:
node(foo) = bar
node[String](foo) match {
case Some(x) = println(x)
case None = println(aww)
}
- easy CaseClass to/from Node/Relation properties marshaling
withTx {
implicit neo =
// create new Node with Case Class Test
val node1 = createNode(Test(Something, 1, 2, 3.3, 10, true))
// or using Option[T] (returning Some[T] if possible)
val nodeOption: Option[Test] = node.toCC[Test]
// create new relation with Case Class Test
node1 -- foo -- node2 Test(other, 0, 1, 1.3, 1, false)
}
- transparent batch processing (simply replace 2 traits to use the same
code for batch- and non batch processing)
For now I am using a simple Github Maven repository.
Neo4j-scala should be usable with the following POM settings:
repositories
repository
idfakod-releases/id
urlhttps://raw.github.com/FaKod/fakod-mvn-repo/master/releases
/url
/repository
/repositories
dependencies
dependency
groupIdorg.neo4j/groupId
artifactIdneo4j-scala/artifactId
version0.1.0/version
/dependency
/dependencies
The Sources are hosted on Github:
https://github.com/FaKod/neo4j-scala/tree/0.1.0
A simple Matrix example GIST is here:
https://gist.github.com/1331556
Enjoy...
PS: Maybe you are using Neo4j Server via Jersey? So sjersey-client may be
interesting for you as well: see @
Githubhttps://github.com/FaKod/sjersey-client/tree/0.1.0 and
this example https://gist.github.com/1366334.
--
Christopher
twitter: @fakod
blog: http://blog.fakod.eu
--
Christopher
twitter: @fakod
blog:
Re: [Neo4j] Gremlin plugin and script engine question
Hey Alfredas,
Be sure to iterate your pipeline
x = []; g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops
4}.iterate(); x
* NOTE: You can also do:
g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops 4} -1
but the convention is no longer with us in Gremlin 1.4-SNAPSHOT.
HTH,
Marko.
http://markorodriguez.com
On Nov 17, 2011, at 7:21 AM, Alfredas Chmieliauskas wrote:
Dear all,
This concerns gremlin plugin and the script engine.
Maybe there's an explanation for this behavior:
1) gremlin x = [];
g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops 4};
gremlin x;
== v[7]
== v[3]
== v[5]
2) gremlin x = [];
g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops 4}; x;
returns nothing...
Thanks,
Alfredas
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Re: [Neo4j] Gremlin plugin and script engine question
What exactly does iterate() do?
A Gremlin expression yields a Pipeline and
PipelineS,E implements IteratorS,E
Thus, a Gremlin expression doesn't return the results of a traversal, only a
lazy iterator for .next()'ing results. For people doing a traversal to yield a
sideEffect (e.g. aggregate, groupCount, etc.), iterate() is there to
while(hasNext()) { next() } for you to fill up your side effect data
structure.
Finally, the Gremlin REPL automagically iterates and System.out.printlns() any
objects in an Iterator it gets so thats why the behavior in the Gremlin REPL
looks like a Gremlin expression returns results.
Hope that is clear,
Marko.
http://markorodriguez.com
A
On Thu, Nov 17, 2011 at 4:07 PM, Marko Rodriguez okramma...@gmail.com wrote:
Hey Alfredas,
Be sure to iterate your pipeline
x = []; g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops
4}.iterate(); x
* NOTE: You can also do:
g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops 4} -1
but the convention is no longer with us in Gremlin 1.4-SNAPSHOT.
HTH,
Marko.
http://markorodriguez.com
On Nov 17, 2011, at 7:21 AM, Alfredas Chmieliauskas wrote:
Dear all,
This concerns gremlin plugin and the script engine.
Maybe there's an explanation for this behavior:
1) gremlin x = [];
g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops 4};
gremlin x;
== v[7]
== v[3]
== v[5]
2) gremlin x = [];
g.v(1).out(from).out(to).aggregate(x).loop(3){it.loops 4}; x;
returns nothing...
Thanks,
Alfredas
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Re: [Neo4j] why g.V[6].both is not returning any thing
Hi, ...or it means that g.V[6] isn't connected to anything. Do this: v = g.V[6].next() v.both v.map() That will tell you if the 6th vertex of V is connected and if it has properties. Marko. http://markorodriguez.com On Nov 16, 2011, at 4:28 AM, Peter Neubauer wrote: Rahul, this probably is an effect of getting a pipe back, that you explicitly need to empty in order to be able to see anything (try g.V[6] -1), which the console and REST endpoints are doing automatically for you. Could you try that? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - NOSQL for the Enterprise. http://startupbootcamp.org/- Öresund - Innovation happens HERE. On Wed, Nov 16, 2011 at 11:56 AM, Rahul Mehta rahul23134...@gmail.com wrote: by neo4j console and also with gremlin On Wed, Nov 16, 2011 at 4:23 PM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Rahul, are you using neo4j.rb or Gremlin/Pacer here? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - NOSQL for the Enterprise. http://startupbootcamp.org/- Öresund - Innovation happens HERE. On Wed, Nov 16, 2011 at 11:49 AM, Rahul Mehta rahul23134...@gmail.com wrote: using neo4j: when m doing : g.E == e[1][1-follow-6] == e[4][5-follow-6] == e[3][7-follow-6] == e[5][8-follow-6] g.V == v[0] == v[1] == v[5] == v[6] == v[7] == v[8] but when m doing g.V[6].both is returning nothing please tell why ? also when m doing g.V[6].map it is not returning anything but when i see from admin and it shows and while g.V.map then also it shows -- You received this message because you are subscribed to the Google Groups neo4jrb group. To post to this group, send email to neo4...@googlegroups.com. To unsubscribe from this group, send email to neo4jrb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neo4jrb?hl=en. -- You received this message because you are subscribed to the Google Groups neo4jrb group. To post to this group, send email to neo4...@googlegroups.com. To unsubscribe from this group, send email to neo4jrb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neo4jrb?hl=en. -- Thanks Regards Rahul Mehta -- You received this message because you are subscribed to the Google Groups neo4jrb group. To post to this group, send email to neo4...@googlegroups.com. To unsubscribe from this group, send email to neo4jrb+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neo4jrb?hl=en. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Simple paging question - Gremlin
Hey Kevin,
g.v(293).in.drop(5).take(5)
and
g.v(293).in[5..9]
(Both return the same, correct result set)
I will be doing some performance tests today on the two, but last week when
I tried them both on fairly heavy queries, the second method seemed faster
(I only say seemed, because I'm hesitant to draw conclusions before I've
properly measured the times)
I've never seen drop() and take() until I saw Peter do it in the Gremlin
documentation. I do not recommend using any of Groovy's collection methods
because they tend to NOT be lazy. The range filter [5..9] is native Gremlin and
lazy/stream-based without intermediate collection construction.
In general, do not use:
collect{}
each{}
drop()/take()
...
Gremlin will have its own lazy version of such constructs and those should be
used.
Enjoy,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Neo4J for semantic graphs + algorithms
Hello, Any information to load OWL specifications into Neo4J or guidance to design algorithms (managment of temporary data is the blocking point)? When you use the OpenRDF SAIL bindings provided by TinkerPop, you will be able to use OpenRDF's OWL reasoners and other tools. Basically, the stack looks like this: OpenRDF Sail TinkerPop GraphSail --- Neo4j 1. OpenRDF Sail is a tool set for working with various aspects of RDF. It is large, heavily developed on, and a standard in the RDF community. 2. TinkerPop GraphSail provides a way to turn any graph database (e.g. Neo4j) into an RDF triple/quad store. 3. Neo4j is a graph database. Hope that helps, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin - how to flatten a tree, and sort
Hi,
I've been trying that query out (slightly modified now to return all nodes
of a different kind, but attached to a node in the first set), on a data set
of around 100K, and I'm getting an OutOfMemoryError:
{
message : GC overhead limit exceeded,
exception : java.lang.OutOfMemoryError: GC overhead limit exceeded,
stacktrace : [ ]
}
My request (for gremlin over REST) is:
script: m = [:]; g.v(id).in('R_PartOf').loop(1){m.put(it.object,
it.loops); true} -1; m.sort{a,b - a.value =
b.value}.keySet()._().in('R_OtherEdge'),
params:
{
id: 284
}
You have the following data structures consuming memory:
1. m
2. m sorted
3. the keyset of m
Perhaps those are sufficiently large to blow our your memory. Perhaps test by,
for example, not getting keySet or not sorting.
When I do large Map-based computations in Gremlin, I use JDBM2 as my map data
structure as its persistent and when it overflows memory, its written to disk.
http://code.google.com/p/jdbm2/
HTH,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Wrong Gremlin results through REST interface
Hey,
To expand on Peter's point. I suspect people are mixing versions of Gremlin.
Gremlin is generally (not usually) backwards compatible from version to
version. If you are using Gremlin REPL, GremlinPlugin, and Gremlin from Neo4j
WebAdmin, its good to make sure you have the same version of Gremlin in
instances. Here is how you check:
GremlinTokens.VERSION
(for old skool Gremlin)
Gremlin.version()
(for new skool Gremlin)
If your versions are not consistent then this may be the reason why you're
traversals in Gremlin REPL are working, but not in Gremlin Plugin (for example).
HTH,
Marko.
http://markorodriguez.com
On Nov 8, 2011, at 8:52 AM, Peter Neubauer wrote:
Hi all (and Romiko),
it might be that this issue, as Romikos, is confusion about the use of
the {}. In Gremlin 1.3, you have to explicitly use filter{} in order
to do this, see https://github.com/neo4j/gremlin-plugin/issues/3 for
an example.
I have locally comitted a documentation example for this, but I am
waiting for the release to finish before pushing it. Could you try
this?
Cheers,
/peter neubauer
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Skype peter.neubauer
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http://startupbootcamp.org/- Öresund - Innovation happens HERE.
On Tue, Nov 8, 2011 at 11:43 AM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
Yup,
I have at least Tathams issue to start with. Will report back and see if it
solves this one too. Feel free to add this example to the issue on the
Gremlin plugin.
On Nov 8, 2011 12:32 PM, Michael Hunger michael.hun...@neotechnology.com
wrote:
There are some weird things going on. Probably have to do with
javax.script.ScriptEngine.eval()
We should investigate this thoroughly.
Perhaps Peter and Marko can spend some cycles on it.
Michael
1) behaviour native gremlin vs
2) Neo4j web console vs.
3) REST-calls
Am 08.11.2011 um 12:02 schrieb Jeroen van Dijk:
HI Michael,
Thanks for this solution. The webconsole now gives me the right results
also for recommendation query. There is however still something weird
when
I use this recommendation query in the gremlin console:
gremlin node = g.v(14260); m = [:].withDefault{0.0}; a_total =
node.inE().count(); node.in().out('owns').sideEffect{union = a_total +
it.inE().count()}.groupCount(m) { it : it += (1.0/(union)) } -1;
m.sort{a,b - b.value = a.value}[0..9]
No signature of method:
com.tinkerpop.blueprints.pgm.impls.neo4j.Neo4jVertex.plus() is
applicable
for argument types: (java.math.BigDecimal) values: [0.0303030303]
Possible solutions: values(), keys(), use([Ljava.lang.Object;),
values(java.lang.Object), is(java.lang.Object),
split(groovy.lang.Closure)
The weird thing is that exact same query does work in the webconsole..
Consider my issue solved though. Thanks a lot.
Jeroen
On Mon, Nov 7, 2011 at 1:25 PM, Michael Hunger
michael.hun...@neotechnology.com wrote:
Jeroen,
could you try to use the alternative syntax:
... groupCount(m) { it : it += 0.1 } ...
It seems to be a problem with evaluation of the string in the
javax.ScriptEngine for Groovy
Here is the output from my web-console:
• gremlin m = [:];g.v(33).bothE().label.groupCount(m) { it }{ it
+= 0.1 } -1;m
• == follows=11
• == owns=48
• gremlin m = [:];g.v(33).bothE().label.groupCount(m) { it : it
+=
0.1 } -1;m
• == follows=1.1
• == owns=4.8
Michael
Am 07.11.2011 um 12:55 schrieb Jeroen van Dijk:
Ok i think I found an example that is independent of my data (adapted
from
http://docs.neo4j.org/chunked/snapshot/gremlin-plugin.html)
Locally:
gremlin m = [:];g.v(33).bothE().label.groupCount(m) -1;m
==follows=11
==owns=48
gremlin m = [:];g.v(33).bothE().label.groupCount(m) { it }{ it += 0.1
}
-1;m
==follows=1.1
==owns=4.8
REST/webadmin console:
gremlin m = [:];g.v(33).bothE().label.groupCount(m) { it }{ it += 0.1
}
-1;m
== follows=11
== owns=48
gremlin m = [:];g.v(33).bothE().label.groupCount(m) { it }{ it += 10
}
-1;m
== follows=11
== owns=48
gremlin
It seems like the closure block is not evaluated (to me as a
Groovy/Gremlin/Neo4j noob)
Michael, I will send you a link to my database in private.
Thanks,
Jeroen
On Mon, Nov 7, 2011 at 12:41 PM, Michael Hunger
michael.hun...@neotechnology.com wrote:
Jeroen,
that would indeed help a lot.
I'll find it.
Michael
Am 07.11.2011 um 12:34 schrieb Jeroen van Dijk:
Hi Michael,
I would like to provide a better example, but my Groovy is quite
poor
so
it
I'll take me some time. However I think the problem isn't in the
JSON
conversion. Because that would mean the results I get would be the
same,
but with a different score
Re: [Neo4j] Ontology in Neo4J REST db
Hi, Anybody knows how to use OWLAPI or any API that can parse and handle these information of a class definition and store them into the Neo4J db? I am not familiar with OWLAPI, but for RDF/RDFS/OWL work, I use GraphSail over Neo4j. https://github.com/tinkerpop/blueprints/wiki/Sail-Ouplementation With a Sail representation of your Neo4j graph, you can then make use of all the tools that work over Sail. See http://openrdf.org ... Good luck, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin - how to flatten a tree, and sort
Hey,
I've played around a bit more, and this is the query that currently works
best for me... would anyone mind reviewing it for me please? Feels a
little like I'm getting the right answer, but the wrong way
gremlin m = [:];
gremlin g.v(162).in('R_PartOf').loop(1){m.put(it.object, it.loops); true}
gremlin m.sort{a - a.value}._()
And, that sort tripped me up a few times :)
Everything looks good except your m.sort{}, which should be something like this:
m.sort{a,b - a.value = b.value}
The provided closure is a comparator. For a java.util.Map, the comparison is
happening between two Map.Entry objects. Thus, your sort needs two inputs (a,b)
and then the value of those Entry objects is a.value and b.value, respectively.
Hope that is clear.
*** Also, note that if you don't want to see output from your g.v(162)...
expression, simply do -1 as it will while(expr.hasNext()) and thus, fill the
map without burdensome System.out.println()s. ***
Enjoy,
Marko.
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Re: [Neo4j] Gremlig Plugin - Paramerterised Queries + Enumeration - Neo4j 1.5M02
Hey,
I can confirm that the gremlin query works in the Console but not in the REST
API.
Console Working:
gremlin g.v(0).outE[[label:'HOSTS']].inV{ it['UniqueId'] == 11761
}.drop(0).take(100)._()
== v[756]
I will log a bug issue on this:
https://github.com/neo4j/gremlin-plugin/issues/3
I notice you are using an old version of Gremlin. I believe you are using 1.1
or less?
If you move to 1.2+, the faster representation of your query is:
g.v(0).out('HOSTS').filter{it.getProperty('UniqueId') == 11761}
Enjoy,
Marko.
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Re: [Neo4j] Gremlin - how to flatten a tree, and sort
Hi,
I would do it like this:
m = [:]
g.v(162).in('R_PartOf').loop(1){m.put(it.object, it.loops); true} -1
m.sort{a, b - a.value = b.value}.keySet as List
In short, fill up a Map (m) with key being the vertex and value being the
number of hops (or times through the loop). Then sort the map by the number
of times through the loop and return the keySet. Since you wanted a List (not a
Set), then as List the Set result.
HTH,
Marko.
http://markorodriguez.com
On Nov 4, 2011, at 10:25 AM, baldric wrote:
I'm very new to much of this, and have a particularly ingrained relational
slant to my career, unfortunately.
I'm in the process of doing a proof of concept for a product, using neo4j,
and gremlin over REST (we're developing in c#) What I'm trying to do at the
moment is load a graph (representing a sort of flexible taxonomy), into a
flattened list. So, given a starting node, find all associated nodes across
a particular relationship type, no matter how far away. I will ultimately
need this in a list, and I want the list sorted by how far away each node is
(am I correct in referring to this as hops?)
Anyway, my best attempt at the unsorted query so far looks something like
this: (by the way, the unique part worries me a little)
x = []; g.v(162).in('R_PartOf').aggregate(x).loop(2){true} -1; x.unique()
(Please try not to laugh too much! :) )
How would I alter this to ensure it is sorted by distance from starting
node?
Thanks in advance!
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Re: [Neo4j] Gremlin - how to flatten a tree, and sort
Sure:
m = [:]; g.v(162).in('R_PartOf').loop(1){m.put(it.object, it.loops);
true}.cap.next().sort{a, b - a.value = b.value}.keySet []
Marko.
http://markorodriguez.com
On Nov 4, 2011, at 12:17 PM, Peter Neubauer wrote:
Can you do it on one line? ;)
Great stuff.
Cheers,
/peter neubauer
GTalk: neubauer.peter
Skype peter.neubauer
Phone +46 704 106975
LinkedIn http://www.linkedin.com/in/neubauer
Twitter http://twitter.com/peterneubauer
http://www.neo4j.org - NOSQL for the Enterprise.
http://startupbootcamp.org/- Öresund - Innovation happens HERE.
On Fri, Nov 4, 2011 at 11:12 AM, Marko Rodriguez okramma...@gmail.com wrote:
Hi,
I would do it like this:
m = [:]
g.v(162).in('R_PartOf').loop(1){m.put(it.object, it.loops); true} -1
m.sort{a, b - a.value = b.value}.keySet as List
In short, fill up a Map (m) with key being the vertex and value being the
number of hops (or times through the loop). Then sort the map by the
number of times through the loop and return the keySet. Since you wanted a
List (not a Set), then as List the Set result.
HTH,
Marko.
http://markorodriguez.com
On Nov 4, 2011, at 10:25 AM, baldric wrote:
I'm very new to much of this, and have a particularly ingrained relational
slant to my career, unfortunately.
I'm in the process of doing a proof of concept for a product, using neo4j,
and gremlin over REST (we're developing in c#) What I'm trying to do at the
moment is load a graph (representing a sort of flexible taxonomy), into a
flattened list. So, given a starting node, find all associated nodes across
a particular relationship type, no matter how far away. I will ultimately
need this in a list, and I want the list sorted by how far away each node is
(am I correct in referring to this as hops?)
Anyway, my best attempt at the unsorted query so far looks something like
this: (by the way, the unique part worries me a little)
x = []; g.v(162).in('R_PartOf').aggregate(x).loop(2){true} -1; x.unique()
(Please try not to laugh too much! :) )
How would I alter this to ensure it is sorted by distance from starting
node?
Thanks in advance!
--
View this message in context:
http://neo4j-community-discussions.438527.n3.nabble.com/Gremlin-how-to-flatten-a-tree-and-sort-tp3480586p3480586.html
Sent from the Neo4j Community Discussions mailing list archive at
Nabble.com.
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Re: [Neo4j] Gremlin - how to flatten a tree, and sort
Hi, Thanks! I will still need to try this out, but the idea (in your first response) kind of feels more or less like what I knew I needed. I have so many questions now based on the responses so far - it feels like I'm just scratching the surface! Once you get it, you can get nasty with Gremlin. And I'm saying nasty with a South African accent so you know its dirty. Firstly, could you explain the differences between map, list, and set? Map = java.util.Map List = java.util.List Set = java.util.Set Google them. Secondly, when you reduced it to a single line, you implemented cap and next I've seen these mentioned before, but don't really get it... 'cap' is a bit advanced and requires some knowledge of the theory of Gremlin/Pipes. Here is an explanation. Some steps in Gremlin are called sideEffects because they have an internal data structure that they are manipulating. groupCount is one such sideEffect step. Internal to groupCount is a map (m) -- updating that map is the side-effect of groupCount. If you cap a sideEffect pipe you are saying: Don't output what the input is, while(next) the input and when that is drained, output the internal side-effect data structure. http://tinkerpop.com/maven2/com/tinkerpop/pipes/0.8/api/com/tinkerpop/pipes/transform/SideEffectCapPipe.html Thus, with ...step.step.groupCount(m).cap you are yielding the internal map of groupCount (m), not the output from the previous step. It is a useful technique when you want to insert the side-effect of groupCount (its map) into the data stream. Finally, all Gremlin expressions are Iterators, so next() just returns the next thing in the stream which is the map we just got from cap. Generally, if you are new to Gremlin, don't try and do massive one-liners. I was just trying to show off cause Peter egged me on. HTH, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] some questions
Hi, 2. Assume I have a big graph in the REST server, what is the best way to remove the whole graph? Of course deleting each node and its relationships and its index is not convenient. Via Gremlin Plugin, you can call g.clear(). HTH, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin help
Hi,
Note that with Blueprints 1.0, you do not have to deal with a commit manager.
You can do:
graph.setTransactionBufferSize(50);
...and then simply do your traversal. No manager.incrCount() needed. I believe
the latest Neo4j release uses Gremlin 1.3 and Blueprints 1.0. ?? Peter?
Take care,
Marko.
http://markorodriguez.com
On Oct 25, 2011, at 12:43 PM, Nuo Yan wrote:
For the record, in case someone else has similar need, I came up with the
following query that does what I described in the last email below (still on
gremlin 1.2 so still using Commit Manager):
manager = TransactionalGraphHelper.createCommitManager(g, 50);
g.v(1).out('foo').transform{[it, it.name,
it.outE('bar').count()]}.aggregate().cap.next().groupBy{it[1]}.each{key,value
- value.sort{a,b - b[2] = a[2]}.eachWithIndex{a,i - if(i 0)
{g.removeVertex(a[0]); manager.incrCounter()}}}
manager.close();
After going through this I got a lot better understanding in Gremlin. Thanks
Peter and Marko.
On Sat, Oct 22, 2011 at 6:04 PM, Nuo Yan yan@gmail.com wrote:
Thanks very much Marko. I researched the query one step at a time and
gained much more knowledge about gremlin.
However, I wanted to do something a little bit different, instead of
comparing the name property of the children nodes to the source node, I
wanted to compare among the siblings of the children nodes (only first level
under the source node) and if there are duplicates, only keep the one with
the biggest degree of bar relationship. (The source node doesn't have a
name property).
For example,
v(1) --foo-- v(2) name: abc --bar-- (15 nodes)
v(1) --foo-- v(3) name: abc --bar -- (20 nodes)
v(1) --foo-- v(4) name xyz --bar-- (15 nodes)
v(1) --foo-- v(5) name xyz --bar-- (25 nodes)
would become:
v(1) --foo-- v(3) name: abc --bar -- (20 nodes)
v(1) --foo-- v(5) name xyz --bar-- (25 nodes)
So instead of doing
g.v(1).sideEffect{x =
it.getProperty('name')}.out('foo').filter{it.getProperty('name').equals(x)}
I proposed doing:
g.v(1).out(foo).transform{[it, it.name,
it.out(bar).count]}.aggregate.cap
to get an array of first level children nodes, their names, and degree of
bar edges like [v(2), abc, 15], [v(3), abc, 20], [v(4), xyz, 15],
[v(5), xyz, 20]
And then I can sort the array by the name property, and iterate through
that array to delete nodes that have a smaller count based on the count
value specified in each sub array.
But since my gremlin knowledge is still very limited, before digging too
much into this proposed solution I want to verify with you that it would
work and see if you have better or easier approach to do it (i.e. maybe one
simple method that I can make use that I'm not aware of). Thanks very much
again.
On Sat, Oct 22, 2011 at 9:40 AM, Marko Rodriguez okramma...@gmail.comwrote:
Hi,
Currently I'm doing the following in my own code with multiple requests
to the standalone neo4j server. I wonder if it's possible to achieve in one
gremlin query/script so that I can post the gremlin query to the server as 1
request and done. What I'm trying to achieve is:
Start from one given node (e.g. v1), get all of the nodes connected
through a given type of relationship (e.g. relationship foo), within all
of these nodes, see if their name property has the same value, and if so,
delete the node (and the foo relationship connected to it) with smaller
outgoing degree (on a specific type of relationship, say, bar). If there
are more than two nodes with the same name property, only keep the one
with biggest outgoing degree (on type bar).
The query below is to warm you up. It will delete all vertices with same
property value as source vertex that are 'foo' related to source vertex.
Given that you are mutating the graph, you will want to deal with
transaction buffers so you don't do one transaction per mutations:
https://github.com/tinkerpop/blueprints/wiki/Graph-Transactions
g.v(1).sideEffect{x =
it.getProperty('name')}.out('foo').filter{it.getProperty('name').equals(x)}.sideEffect{g.removeVertex(it)}
-
To do the stuff with the smaller counts, etc. You can do:
g.v(1).sideEffect{x =
it.getProperty('name')}.out('foo').filter{it.getProperty('name').equals(x)}.transform{[it,
it.outE('bar').count()]}.filter{it[1] 0}.aggregate.cap.next().sort{a,b -
b[1] = a[1]}.eachWithIndex{a,i - if(i 0) g.removeVertex(a[0])}
There you go! One big fatty Gremlin query to solve your problem.
I would recommend going through each step and seeing what it returns so
you understand what is going on Again, given that you are mutating the
graph, be sure to be wise about transactions.
Enjoy!,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Gremlin help
Hi,
Currently I'm doing the following in my own code with multiple requests to
the standalone neo4j server. I wonder if it's possible to achieve in one
gremlin query/script so that I can post the gremlin query to the server as 1
request and done. What I'm trying to achieve is:
Start from one given node (e.g. v1), get all of the nodes connected through a
given type of relationship (e.g. relationship foo), within all of these
nodes, see if their name property has the same value, and if so, delete the
node (and the foo relationship connected to it) with smaller outgoing
degree (on a specific type of relationship, say, bar). If there are more
than two nodes with the same name property, only keep the one with biggest
outgoing degree (on type bar).
The query below is to warm you up. It will delete all vertices with same
property value as source vertex that are 'foo' related to source vertex. Given
that you are mutating the graph, you will want to deal with transaction buffers
so you don't do one transaction per mutations:
https://github.com/tinkerpop/blueprints/wiki/Graph-Transactions
g.v(1).sideEffect{x =
it.getProperty('name')}.out('foo').filter{it.getProperty('name').equals(x)}.sideEffect{g.removeVertex(it)}
-
To do the stuff with the smaller counts, etc. You can do:
g.v(1).sideEffect{x =
it.getProperty('name')}.out('foo').filter{it.getProperty('name').equals(x)}.transform{[it,
it.outE('bar').count()]}.filter{it[1] 0}.aggregate.cap.next().sort{a,b -
b[1] = a[1]}.eachWithIndex{a,i - if(i 0) g.removeVertex(a[0])}
There you go! One big fatty Gremlin query to solve your problem.
I would recommend going through each step and seeing what it returns so you
understand what is going on Again, given that you are mutating the graph,
be sure to be wise about transactions.
Enjoy!,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Neo4j, Gremlin and Campaign data
Digging it up was the easy part :D. Writing it was the hard part. This is the fellow who wrote it: http://twitter.com/#!/davefauth Marko. http://markorodriguez.com On Oct 18, 2011, at 7:33 AM, Peter Neubauer wrote: Hi all, the other day Marko dug this up - using Neo4j with Campaign data. Pretty cool! http://s113319.gridserver.com/?p=48 Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/- Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Article: The Coming SQL Collapse
Hi, This is not conducive to Baysian-based reasoning, evidential reasoning, other forms of logics (classical and non-classical) How would you model those to a suitable domain model? Can you give a good example? Michael Here is an article that argues for support of other data semantics in the Web of Data (RDF world) beyond description logics. In here, you will find examples of other forms of reasoning. http://arxiv.org/abs/0905.3378 Unlike the triple/quad-store world, graph databases provide a very generic data model with limited constraints on meaning. Unfortunately (in my opinion), graph databases like OrientDB and DEX employ typing at the graph database level. Neo4j provides it at the Spring Data Graph level -- a level above. This is good in that Neo4j is not pushing a world view to low into the stack. The world of RDF, on the other hand, and its strong bent towards OWL (description logic) makes it such that the entire technology stack is mixed up with this logic. And, while this logic is very cool, its not the only way to do things -- the only way to view the world. however, at some point, there is always an assumption, and the foundational assumption of graph databases is all reasoning is best with a linked list data structure. See ya, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Mahout, and Migrating from JPA/Hibernate/MySQL to Neo4j?
Hi Deejay, 1. We're using Mahout as a recommendation system. Has anyone had any success plugging Neo4j into this? I work with various companies using graph databases to do recommendation. Moreover, a couple of them are also experimenting with Mahout over MySQL and Hadoop. I have never thought to think about backing Mahout by a graph database. That is an interesting idea... Here are three thoughts that are related (though do not directly address your question): 1. With Mahout (as I understand it since a few versions back), only single relational data can be processed. That is, it only supports data of the form: X likes[weight] Y, where weight can be binary or rational. When a domain model is sufficiently complex: people liking things, people knowing each other, people working in the same, similar, etc. places, and products having features, designers, etc. there is more information in the domain that can be capitalized on for recommendation. 2. With pure graph-based recommendation, no recommendation model is generated (intermediate data structure) as recommendations are calculated on the fly over the raw graph using traversal techniques. Traversals can propagate over more complex relations and are not limited to X likes[weight] Y or, better yet, such basic relations can be derived through implicit relations (i.e. paths) [ http://markorodriguez.com/2011/02/08/property-graph-algorithms/ ]. Along this line of thought, the raw graph representation of your domain can be used for more than just recommendation --- e.g. path analysis, global ranking, searching, reasoning, abstraction, etc. [ http://markorodriguez.com/2011/07/14/graphs-brains-and-gremlin/ ] 3. With various forms of graph sampling/weighting, it is possible to put as many clock cycles (thus, compute time) as desired into the determination of a recommendation -- generally, more clock cycles yields greater accuracy. However, with accumulative methods, it is possible to reach an ergodic state [ http://en.wikipedia.org/wiki/Ergodicity ] whereby the contribution of more clock cycles does not yield more information (i.e. does not alter the order of the resultant recommendation ranking). While your question was about overlaying Mahout on top of Neo4j, I argue that by using Neo4j in its native form (through its API and its approach to data analysis), there is much more beyond recommendation that you can exploit from your domain model. To conclude, I recently wrote up a post on graph-based recommendation that may be of interest to you: http://markorodriguez.com/2011/09/22/a-graph-based-movie-recommender-engine/ Good luck with your explorations, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Neo4J + ThingWorx Presentation from QCon...
I thoroughly enjoyed the presentation. Well done. Marko. http://markorodriguez.com On Oct 11, 2011, at 2:01 PM, Rick Bullotta wrote: ...is now online. http://www.infoq.com/presentations/Graph-Database-Power-Web-of-Things Enjoy. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin syntax for multiple paths in one call
Hey,
If I want to get the following
g.V(0).out('Friends')
and
g.V(0).in('Likes')
This is the world of split and merge. The syntax for this is not the sexiest,
but as it stands:
g.v(0)._.copySplit(_().out('Friends'), _().in('Likes')).fairMerge
copySplit will take what comes into it and copy it to its internal pipes (in
this case, 2 internal pipes). Then fairMerge will, in a round robin fashion,
merge the output of the two internal pipes into a single pipe. Thus, split the
pipeline, then merge it back into a single pipeline.
For example, over the play TinkerPop graph:
gremlin g = TinkerGraphFactory.createTinkerGraph()
==tinkergraph[vertices:6 edges:6]
gremlin g.v(1)._.copySplit(_().out('created'),_().out('knows')).fairMerge
==v[3]
==v[2]
==v[4]
We haven't developed split/merge much. If you have any ideas for syntax, that'd
be great.
NOTE: If they were both out, then you can simply do:
g.v(0).out('friends','likes')
Good luck,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Gremlin syntax for multiple paths in one call
Hey, Your answer is correct too, though its not lazy. However, I suspect its more understandable. Marko. On Oct 4, 2011 8:31 AM, Peter Neubauer peter.neuba...@neotechnology.com wrote: Nice one, will change the docs. /peter Sent from my phone. On Oct 4, 2011 5:20 PM, Marko Rodriguez okramma...@gmail.com wrote: Hey, If I want to get... ___ Neo4j mailing list User@lists.neo4j.org http... ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] C# REST binding / wrapper
Hey Romiko,
http://romikoderbynew.com/2011/07/30/neo4jclient-primer/
That is really cool how you build a Gremlin expression in C# using a fluent
pattern and then, I suspect, transform it to the appropriate Gremlin string
representation for transport over the wire to Neo4j REST Server. Is that what
you are doing? If so, that is a neat way to build language bindings that are
not just server.eval(some.big.fat.string.all.old.skool.rdbms.style)?
Finally, in a similar note, TinkerPop is generalizing Gremlin away from a
particular language implementation. We want to provide the Gremlin-style to
any JVM language, not just Groovy. We plan to have Gremlin_scala out in the
next release... E.g.:
gremlin-groovy: g.v(1).out('knows').name.filter{it == 'josh'}
gremlin-scala: g.v(1).out(knows).property(name).filter{_ == josh}
There is an strong conceptual overlap to how you are doing your C# binding and
how Gremlin is becoming JVM language agnostic makes me think. :/
Anywho, I like the work you did. Thank you for sharing,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Some questions about design when using neo4j
Hey, If you want to play with JUNG over Neo4j, you can do it via TinkerPop. Graph g = new Neo4jGraph(/tmp/neo4j); GraphJung jung = new GraphJung(g); That GraphJung object is a implementation of the JUNG Interfaces and can be processed by the JUNG algorithms package. https://github.com/tinkerpop/blueprints/wiki/JUNG-Ouplementation HTH, Marko. http://markorodriguez.com On Sep 28, 2011, at 1:06 AM, Peter Neubauer wrote: Gen, I guess there is nothing out of the box right now, but you could get inspiration from http://jung.sourceforge.net/doc/api/index.html, especially http://jung.sourceforge.net/doc/api/edu/uci/ics/jung/algorithms/flows/EdmondsKarpMaxFlow.html and implement one or just use it on a toy graph to test it out? Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/- Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Sat, Sep 3, 2011 at 12:33 AM, Benjamin Gustafsson benjamingustafs...@gmail.com wrote: Just in case there are any graph experts out there that want to exercise their brains. (Its quite a while since I studied algorithms and optimization regarding graphs. :-) I'm able to implement a algorithm described in pseudocode (if anyone knows a good algorithm for my special case below). I have the transportation problem and need to find a preferably small (not necessarily smallest) set of nodes that transports a certain amount of credit/commodity from source node S to sink node T. All edges have a capacity stated as a attribute for the edge, this can be read while traversing the graph. Transportation cost for commodity/credit in the graph is zero. The only cost in this graph problem is computation time to *find a set of paths delivering all the commodity*(in my case credit). The path lengths chosen are not important. (This is the standard ripplepay problem, but I didn't like the algorithms used by the original ripplepay implementation. It does not scale up to millions of users. It is not fast enough.) http://en.wikipedia.org/wiki/Transportation_network_%28graph_theory%29 And I also need a quick way of analysing if it is possible to send all commodity across the network. If the amount commodity to be sent is lower than max flow. (lower than min cut). There will initially be clusters with very few edges connecting the clusters. If the nodes are in different clusters the min cut can be really easy/*quick* to find (if we do it the right way). http://en.wikipedia.org/wiki/Max-flow_min-cut_theorem Any implementations for neo4j already available regarding my special case? -- //Benjamin Gustafsson ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Neo4J Rest server support SPARQL??
Hey, After adding nodes and relationships into Neo4J REST server using REST API. How do I read data from the database using SPARQL? Does the database support SPARQL? Neo4j is not an RDF database in its raw form. Its data model is a bit more complicated than RDF and as such, is not amenable to SPARQL which assumes only an edge-labeled graph. However, with that said, the pattern matching functionality of Cypher is somewhat analogous to SPARQL so you might find solace in that. Moreover, you can also use Gremlin for pattern matching, though it doesn't have the same look-and-feel as SPARQL (see https://github.com/tinkerpop/gremlin/wiki/SPARQL-vs.-Gremlin ). Next. If you actually have used GraphSail (via Blueprints) to model your data as an RDF graph in Neo4j, then you can access it via Sesame SPARQL engine --- however, as it stands, not via the Neo4j REST server without rolling your own extension. If you are so inclined, you can either use Rexster (http://rexster.tinkerpop.com) and its SPARQL kibble or steal the code in Rexster's SPARQL kibble and make it work for Neo4j Server (shouldn't be more than an a few hours work). see http://rexster-kibbles.tinkerpop.com/ https://github.com/tinkerpop/rexster-kibbles/tree/master/sparql-kibble Hope that is clear, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] how to get the User who has been B Followed who has Followed Back.
Hi,
I have some relation like this:
http://neo4j-community-discussions.438527.n3.nabble.com/file/n3352328/follow.jpg
what should I do to get the users who has been B Followed and has Followed
back to B.
In the image the result should be (A).
In Gremlin (http://docs.neo4j.org/chunked/snapshot/gremlin-plugin.html)
Marko will provide, have no time to test it to be exact :)
If I understand your query correctly, then its:
g.v(1).out.filter{it.out[[id:1]].hasNext()}
Start from vertex 1(B), go to its outgoing adjacent neighbors. For each of
those neighbors, make sure there is at least one link back to vertex 1.
HTH,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Neo4j low-level data storage
shameless plug explanation=my blog There is no shame in producing good work and sharing it with others. Marko. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin Sort Syntax Help
Hey,
Using the REST API
g.v(0).out.unique().sort{it.Name}.toList()
Cool.
works but i can't get
t = new Table();
g.v(0).out.as('friend').table(t).sort{it.Name} -1;
t;
to sort correctly.
Table will simply pass the object through itself (it is a side-effect step).
Thus, you are sorting on 'out name' in the stream, not on the table.
t = new Table();
g.v(0).out.as('friend').table(t){it.Name} -1
t.sort();
OR
t = new Table();
g.v(0).out.as('friend').table(t) -1
t.sort{it.Name};
---depends on what you want stored in the table. the first stores the Name, not
the vertex.
*ANALOGOUS TO THE LAST, BUT MORE CONCISE
g.v(0).out.as('friend').table.cap.next().sort{it.Name}
**
and how would i sort
g.v(0).out.as('friend').out.as('moreFriend').sort( on friend.Name )
Also, can you point me to some documentation on this and other commends that
can be preformed on this pipe. I have been searching and have not found
anything straight forward (could be me...)
t = new Table();
g.v(0).out.as('friend').out.as('moreFriends').table(t) -1
t.sort{it[0].Name}
--- or if you want to use column names as opposed to column indices:
t.sort{it.getColumn('friend').Name}
I just added some of this to the Gremlin Wiki.
https://github.com/tinkerpop/gremlin/wiki/Pattern-Match-Pattern (at
bottom)
Thanks for the question,
Marko.
http://markorodriguez.com
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[Neo4j] A Note on Writing Performant Gremlin
Hi Gremlin+Neo4j+OrientDB people, I apologize for the cross list posting, but this is an important piece of information for those using Gremlin with their respective graph databases. I've noticed lots of people use the very friendly notation of Element.key to get the property value of an Element. Note that in Gremlin, this mapping from Element.key to Element.getProperty(key) requires Java reflection and is a costly operation. The cost of a pretty traversal expression is time. Please read over this Wiki page for notes on optimizing your Gremlin queries: https://github.com/tinkerpop/gremlin/wiki/Path-Optimizations ..especially the first section: Avoid Element Property Selection using Key Finally, note that these times are with respect to Gremlin 1.3-SNAPSHOT which will have a stable release September 21st. Thanks so much and again, apologies for the cross post. Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] A Note on Writing Performant Gremlin
Hey, just to be clear, Would it be safe to say that the compile time for g.v(0).out.out -1 would be slower than g.v(0).out().out() -1 and slower than g.v(0).outE().inV().outE().inV() -1 The fastest would be g.v(0).out().out(). It is also surprising that the compile times that you have are an order of magnitude greater for the the condensed notation. thanks for the info. The reason why there is a difference in speed is because Groovy's dynamic programming is based on Java reflection which is slow. However, compiling a pipeline is the least of your time relative to evaluating your traversal. We are currently working on Gremlin_scala and Gremlin_jython. Gremlin_scala provides a nearly identical syntax with anonymous functions (e.g. filter(_.getProperty(age) 10)) and so, for many, this might be the way to go as its much faster with static typing and none of the runtime dynamic programming techniques used by Groovy. In essence, we plan for the future of Gremlin to be a graph traversal specification with implementations in multiple JVM languages so developers can pick which ever host language (JRuby, Groovy, Scala, Jython, Clojure, etc.) makes them happiest when traversing graphs in the Gremlin-esque style. Hope that is clear, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Returning arbitrary data from gremlin
Hi,
Also, there table-step documentation for Gremlin is in Pattern Match Pattern:
https://github.com/tinkerpop/gremlin/wiki/Pattern-Match-Pattern
Side note:
t = t.collect {
outN = it.outV.toList().get(0);
inN = it.inV.toList().get(0);
[outN.type, outN.key, inN.type, inN.key].join(,);
};
..it is more efficient to do:
t = t.collect {
outN = it.outV.next();
inN = it.inV.next();
[outN.type, outN.key, inN.type, inN.key].join(,);
};
Though, as you say, probably best to use 'table' with column closures.
If you can frame you questions in terms of the graph diagrammed here
https://github.com/tinkerpop/gremlin/wiki/Defining-a-Property-Graph , it will
be much easier for us to tell you the answer than to parse your code which
don't understand the underlying data model.
Good luck,
Marko.
http://markorodriguez.com
On Sep 11, 2011, at 10:29 AM, Peter Neubauer wrote:
Xavier,
also, for the table construction, have a look at the example at
http://docs.neo4j.org/chunked/snapshot/gremlin-plugin.html#rest-api-send-a-gremlin-script---json-encoded-with-table-results,
if that helps?
Cheers,
/peter neubauer
GTalk: neubauer.peter
Skype peter.neubauer
Phone +46 704 106975
LinkedIn http://www.linkedin.com/in/neubauer
Twitter http://twitter.com/peterneubauer
http://www.neo4j.org - Your high performance graph database.
http://startupbootcamp.org/- Öresund - Innovation happens HERE.
http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party.
On Sun, Sep 11, 2011 at 5:35 PM, Xavier Shay xavier+ne...@squareup.com
wrote:
I feel I should be able to use the Table object, but couldn't figure it out
(is there explicit API documentation for it anywhere?)
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Re: [Neo4j] Aggregate queries
Hey,
m = [:];
g.idx(user).get(key, %query%*)._()[0..5].sideEffect { x = it.key
}.out.in.uniqueObject.loop(3) { it.loops 2 }.sideEffect {
if (!m[x]) { m[x] = 0; };
m[x]++
} -1;
m;
Tips:
1. do g.idx(user).get(key, %query%*)[0..5]
- _() is not needed.
2. use can use single quotes g.idx('user').get('key','%query%*')
3. use groupCount(m) instead of that last sideEffect.
* The [0..5] allows me to page through the index to avoid one massive query.
* I'm thinking perhaps the aggregate step would be useful, but I haven't
figured out how to use it yet.
aggregate is just a way to collect everything up at a single step before moving
to the next step. Typical use case:
g.v(1).out('friend').aggregate(x).out('friend').except(x)
- my friends' friends who are not my friends.
* I will unroll the loop as Marko suggested when I get to optimizing it
Cool. Realize that Gremlin 1.3 (coming out in a couple of weeks) is nearly 2-3x
faster on most traversals as we have done many many performance optimizations.
However, still unrolling loops will be faster than not doing so.
Good luck with your project.
Keep the questions/thoughts coming,
Marko.
http://markorodriguez.com
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Re: [Neo4j] chain TraversalDescription?
Hi,
I would do this using Gremlin as such:
g.v(1).out('read').in('wrote').uniqueObject.out('pet').name
If you are vertex 1 (g.v(1)),
then you will go to the books you read,
then to the authors of those books,
then because you might have read two Stephen King books, you will
remove duplicates,
then to their pets,
and then to the names of those pets.
This assumes a graph of the form:
person ---read-- book ---wrote--- person ---pet---
animal[string:name]
Take care,
Marko.
http://markorodriguez.com
On Sep 9, 2011, at 8:48 AM, Linan Wang wrote:
Hi,
say people read books, books are written by authors, authors has dogs,
then how to reach the dogs of authors of books i've read? when i'm
also a writer, also have dogs, the TraversalDescription seems
inefficient since it'll also traverse my own books and dogs first,
before my customised StopEvaluator stops the expansion process.
my feeling is RelationshipExpander is the way to go but stucked at the
problem to get the depth info. my goal is to have the designated
RelationshipExpander to tell traverser that at depth 1 only looking
for OUTGOING read relationship, depth 2 for INCOMING wrote
relationship and depth 3 for OUTGOING has relationship. any comment is
appreciated! thanks.
--
Best regards
Linan Wang
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Re: [Neo4j] Gremlin pipes broken in 1.5
Hi,
This error seems to be an issue with depedencies. Are you using an TinkerPop
dependency/s in your project. I believe Neo4j 1.5.M01 is depending on
Blueprints 0.9 which does have the getInEdges(String...) method (similarly for
getOutEdges(). Perhaps you are depending on Blueprints 0.8 somewhere in your
project and the class loader is getting confused?
Also, you don't need an identity pipe. You can do:
g.v(1).both
Marko.
http://markorodriguez.com
On Sep 9, 2011, at 1:29 PM, Xavier Shay wrote:
Hello,
I have just upgraded to neo4j 1.5 (brew install neo4j --HEAD) and am getting
the following exception whenever I try to use a pipe:
curl -H Accept:application/json -X POST -d '{script:g.v(1)._().both;}'
-H Content-Type:application/json
http://localhost:7474/db/data/ext/GremlinPlugin/graphdb/execute_script;
{
message :
com.tinkerpop.blueprints.pgm.impls.neo4j.Neo4jVertex.getInEdges([Ljava/lang/String;)Ljava/lang/Iterable;,
exception : java.lang.AbstractMethodError:
com.tinkerpop.blueprints.pgm.impls.neo4j.Neo4jVertex.getInEdges([Ljava/lang/String;)Ljava/lang/Iterable;,
stacktrace : [... trim, see
https://gist.github.com/1d6df2b03fa4d402ade3... ]
}
The same command without .both works as expected. Other pipe methods such
as outE all cause the same exception. This was working with 1.4, and I
couldn't find any mention of backwards incompatibility in the Gremlin
changelog.
I'm not sure how to debug this further. Any suggestions?
Cheers,
Xavier
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Re: [Neo4j] Aggregate queries
Hi,
Thanks James. Here is how I would do it -- groupCount is not needed.
g.idx(index_name)[[key:value]].both.loop(1){it.loops depth}.count()
Note: Be wary of this query. Make sure the branch factor of your graph is
sufficiently small or the depth to which you are exploring is sufficiently
small. With a large branch and depth, you can easily touch everything in your
graph if your graph has natural statistics. (
http://en.wikipedia.org/wiki/Scale-free_network )
Also, if you want to get fancy, what I like to do, is unroll my loops to
increase performance. Given that the while construct of your loop step is
simply depth, you can append an appropriate number of .both steps.
traversal = g.idx(index_name)[[key:value]];
for(i in 0..depth) {
traversal = traversal.both;
}
traversal.count();
Finally, 'both' is for undirected traversals. Use 'out' for outgoing traversals
(follow the direction of the arrows) and 'in' for incoming traversals.
https://github.com/tinkerpop/gremlin/wiki/Gremlin-Steps
HTH,
Marko.
http://markorodriguez.com
Xavier Shay wrote:
For all nodes in a particular index, how many other nodes are they
connected to at depth X?
Marko will be able to improve upon this, but try something like this (this
is untested)...
m = [:]
depth = 10
index_name = vertices
index_key = name
index_nodes = g.idx(index_name).get(index_key,Neo4jTokens.QUERY_HEADER +
*).
index_nodes._().both.groupCount(m).loop(2){it.loops depth}
m.size()
- James
--
View this message in context:
http://neo4j-community-discussions.438527.n3.nabble.com/Neo4j-Aggregate-queries-tp3317720p3317876.html
Sent from the Neo4j Community Discussions mailing list archive at Nabble.com.
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Re: [Neo4j] Aggregate queries
Hey,
Won't this count dupes more than once?
Xavier's requirements of how many other nodes are they connected sounds
like you should only count uniques, and that's why I am checking the size of
groupCount map instead of using count(). Instead of a map you could use a
Set with aggregate(), but I wasn't sure if they'd have the aggregate-loop
fix yet.
Then add a uniqueObject to the pipeline.
g.idx(index_name)[[key:value]].both.loop(1){it.loops
depth}.uniqueObject.count()
Also Xavier said, For all nodes in a particular index. I took that to mean
all nodes in an index, not all nodes for a particular value in an index,
hence the wildcard query:
index_nodes = g.idx(index_name).get(index_key,Neo4jTokens.QUERY_HEADER +
*)
However, I am not sure/can't remember if you can do a wildcard query without
at least one leading character.
Oh then yea, the %query% header can be used.
Marko.
http://markorodriguez.com
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Re: [Neo4j] Spring Data Neo4J vs. Tinker Pop's Frames/BluePrints?
Hi, My thoughts on the matter. Frames is bare-bones simple and the library is tiny. If you simply want to do the following, then Frames is cool: 1. Use annotated interfaces to define a Graph-to-Object mapping. (at the cost of Java reflection) 2. Use your objects as a way to schemify (constrain) your graph. 3. Put and get objects out of your graph and abandon the vertex/edge mental model. You can simply think in terms of Java objects. - this is optional as I tend to use Frames only for data ingest. 4. (NEXT RELEASE) use Pipes or Gremlin to define abstract/inferred/virtual relationships between your domain objects. Frames does not fit into a larger framework (outside of TinkerPop). Unfortunately, I don't know Spring, but from what I can tell, its a heavily used ?web application? framework and has lots of bells and whistles so it will definitely be more feature rich. As Alfredas Chmeiliauskas (wow thats a crazy last name) says, there are lots of ways to mix and match things so don't feel that you will be trapped by a technology. Its easy to move between raw Neo4j/Blueprints, Cypher/Gremlin, etc. The only big choice I believe you make is whether you go Neo4j Server or Rexster as you can't really mix and match those two. In many of my projects I use Neo4j Server with parsers written in Frames and custom extensions using Gremlin. I also, in another, use Rexster with a Neo4j batch inserter (no Frames) and only the Neo4j algos package. Sorta depends on what the project demands... HTH, Marko. http://markorodriguez.com On Sep 2, 2011, at 3:33 AM, Michel Domenjoud wrote: Thanks for your answers! @Anders: Thanks, I noticed it, but I was more precisely wondering about Frames API, which brings similar functionalities to Spring Data. 2011/9/2 Anders Nawroth and...@neotechnology.com Note that Gremlin is supported by Spring Data Graph, it's mentioned here: http://www.springsource.org/node/3208 /anders 2011-09-02 11:05, Peter Neubauer skrev: Michel, IMHO the Spring Data Graph is a much broader approach to the problem, although it brings with it more dependencies. I guess it is a matter of choice. I would go for Spring Data Graph personally. Cheers, /peter neubauer GTalk: neubauer.peter Skype peter.neubauer Phone +46 704 106975 LinkedIn http://www.linkedin.com/in/neubauer Twitter http://twitter.com/peterneubauer http://www.neo4j.org - Your high performance graph database. http://startupbootcamp.org/- Öresund - Innovation happens HERE. http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing party. On Fri, Sep 2, 2011 at 10:38 AM, Michel Domenjoudmdomenj...@octo.com wrote: Hi everybody, What are Neo4J forecasts about Tinker Pop's Frames and Blueprints frameworks, now there is Spring Data Graph framework? I saw that Neo4J guys are working on both projects, so do you have any preference for using one framework rather than the other? Michel. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] 10 questions
Oh, I didn't see this:
(use twitter example: my followees' followers)
Then the query I provided in the previous email:
g.v(1).out('livesIn').sideEffect{city =
it}.back(2).out.out.filter{it.out('livesIn').next().equals(city)}.groupCount(age){it.age}.groupCount(gender){it.gender}
would now be:
g.v(1).out('livesIn').sideEffect{city =
it}.back(2).in('follows').in('follows').filter{it.out('livesIn').next().equals(city)}.groupCount(age){it.age}.groupCount(gender){it.gender}
as in('follows') is someone's followees (i.e. the people that follow me).
Enjoy,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Hyperedges in Neo4j
Hey, I think a traversal should in principal be performed with a query language that is not turing complete so we can guarantee termination. Turning completeness is not the lower bound for non-guaranteed termination. You can't guarantee completion in a regular language when your String (data structure) is a graph. E.g. a* The only languages guaranteed to complete are Star-free languages. That is, those that don't allow for recursion. See ya, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] problem in SPARQL querying
Hey, Even on closing the manager, I did not see any change.. any further ideas?? Thanks! The best thing to do is not dive straight into a complex SPARQL query, but look to see if the particular triples you think are lost are actually there. You can do this with simple SPARQL queries or drop into Gremlin and search around. The SPARQL query engine you are using was developed by Aduna and has been in use for many many years so I doubt there is a problem with their engine. I suspect there is some missing data. ?? .. Or perhaps your query is wrong. ?. Good luck, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
[Neo4j] FluentPipeline with Pipes
Hi everyone,
For those on the Gremlin-users mailing list, this is not new. However, for
others, I thought you would like to see some work over at TinkerPop that I'm
really diggin'.
In Pipes 0.8-SNAPSHOT, we have made it so that its much easier to construct
Gremlin-esque traversals in native Java. The new killer pipe is called
FluentPipeline.
It works as such:
Graph g = new Neo4jGraph('/tmp/mygraph');
ListString friendsProjectNames = new
FluentPipeline(g.getVertex(1)).out(knows).out(created).property(name).toList()
In short, every Pipe in Pipes has an associated (in many cases, many
associated) methods in FluentPipeline that to allow for this style of traversal
construction. As you may realize, the only reason Gremlin still exists is
because of the ease by which closures (~anonymous functions) can be defined in
Groovy (as well as some other random meta-programming stuff). With
FluentPipeline, inner-classes are required which are very verbose.
See the last two code blobs of
https://github.com/tinkerpop/pipes/wiki/FluentPipeline that compare pure Java
and Groovy.
This work along with some vast speed improvements to Gremlin will be seen in
Gremlin 1.3 which will probably trickle up to Neo4j at version 1.4.3.
Enjoy,
Marko.
http://markorodriguez.com
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Re: [Neo4j] problem in SPARQL querying
Hi Shri,
Question: Why do you have a TransactionalGraphManager as, in your code, you are
not writing anything to disk? This makes me believe that you have another
snippet of code that is writing data to the graph. Are you sure all your data
is in the graph? -- How did you construct dataset (from new
Neo4jGraph(dataset)).
Thanks,
Marko.
http://markorodriguez.com
On Aug 31, 2011, at 6:37 AM, shri wrote:
Hi all,
I am working with Neo4j system and Sparql queries as a part of my thesis
and I am very very new these concepts. I have loaded the RDF dataset into
Neo4j and now trying to query the results. My problem is, only half of my
query is working and giving results but the query as a whole is not
returning any result. this is leaving me clueless and I have no idea why
this is happening..Kindly help me out with a solution.Thanks in advance!!
I have used the Sail interface for query parsing and evaluating
Here is the snippet:
Neo4jGraph neo = new Neo4jGraph(dataset);
Sail sail = new GraphSail(neo);
sail.initialize();
CommitManager manager =
TransactionalGraphHelper.createCommitManager(neo, 1);
SailConnection sc= sail.getConnection();
Query1 ext=new Query1();
SPARQLParser parser = new SPARQLParser();
CloseableIteration? extends BindingSet, QueryEvaluationException
sparqlResults;
String queryString = PREFIX bsbm:
lt;http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/gt; +
PREFIX rdf: lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#gt; +
PREFIX rdfs: lt;http://www.w3.org/2000/01/rdf-schema#gt; +
SELECT DISTINCT ?product ?label +
WHERE { +
?product rdf:type
lt;http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductType2gt;
. +
?product rdfs:label ?label . };
/*?product bsbm:productFeature
lt;http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductFeature35gt;.;
+
?product bsbm:productFeature
lt;http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/instances/ProductFeature36gt;
. +
?product bsbm:productPropertyNumeric1 ?value1 . +
FILTER (?value1 3) } +
ORDER BY ?label +
LIMIT 10;*/
try {
ParsedQuery query = parser.parseQuery(queryString,
http://www4.wiwiss.fu-berlin.de/bizer/bsbm/v01/vocabulary/;);
System.out.println(\nSPARQL: + queryString);
sparqlResults = sc.evaluate(query.getTupleExpr(), query.getDataset(),
new EmptyBindingSet(), false);
while (sparqlResults.hasNext()) {
System.out.println(sparqlResults.next());
}
IS IT ANY THING TO DO WITH INDEXING ??
P.S The commented portion of my query in the snippet is NOT working
cheers,
shri
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Re: [Neo4j] problem in SPARQL querying
Hi,
Where are you defining your RDFHandler (TripleHandler). Can I see that class
please?
Thanks,
Marko.
http://markorodriguez.com
On Aug 31, 2011, at 7:25 AM, shri wrote:
Hi Marko,
Yes I have another separate file for loading the data( .NT format). Let me
know if I should tell anything more clearly, sorry for being slow...
snippet :
Neo4jGraph neo = new Neo4jGraph(dataset);
Sail sail = new GraphSail(neo);
sail.initialize();
CommitManager manager =
TransactionalGraphHelper.createCommitManager(neo, 1);
SailConnection sc= sail.getConnection();
for (String file: args)
{
System.out.println(Loading + file + : );
loadFile(file, sail.getConnection(), sail.getValueFactory(),
manager);
System.out.print('\n');
}
private static void loadFile(final String file, SailConnection sc,
ValueFactory vf, CommitManager manager) throws RDFParseException,
RDFHandlerException, FileNotFoundException, IOException {
NTriplesParser parser = new NTriplesParser(vf);
TripleHandler handler = new TripleHandler(sc, manager);
parser.setRDFHandler(handler);
parser.setStopAtFirstError(false);
parser.setParseErrorListener(new ParseErrorListener() {
@Override
public void warning(String msg, int lineNo, int colNo) {
System.err.println(warning: + msg);
System.err.println(file: + file + line:
+ lineNo + column:
+colNo);
}
@Override
public void error(String msg, int lineNo, int colNo) {
System.err.println(error: + msg);
System.err.println(file: + file + line:
+ lineNo + column:
+colNo);
}
@Override
public void fatalError(String msg, int lineNo, int
colNo) {
System.err.println(fatal: + msg);
System.err.println(file: + file + line:
+ lineNo + column:
+colNo);
}
});
parser.parse(new BufferedInputStream(new FileInputStream(new
File(file))),
http://dbpedia.org/;);
}
}
Cheers,
Shri
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Re: [Neo4j] problem in SPARQL querying
Hi,
When you are done with the file, you should close your manager.
I believe should do the trick:
public void endRDF() throws RDFHandlerException {
manager.close();
}
// NOTE: I don't know the specifics of RDFHandler, but it sounds like endRDF()
is the method called when the file handler is complete. ?
This way, the last triples inserted, but not committed, are committed.
Perhaps that is your problem? ... you are missing the tail end of your RDF file.
However, if you are simply calling a SPARQL query within the same thread then
the uncommitted triples should be visible to your code.
What are your thoughts on the matter?,
Marko.
http://markorodriguez.com
On Aug 31, 2011, at 7:45 AM, shri wrote:
Hello Marko,
here is my TripleHandler class:
public class TripleHandler implements RDFHandler {
private SailConnection sc;
private CommitManager manager;
public TripleHandler(SailConnection sc, CommitManager manager) {
this.sc = sc;
this.manager = manager;
}
public void handleComment(String arg0) throws RDFHandlerException {
}
public void handleNamespace(String arg0, String arg1)
throws RDFHandlerException {
}
public void handleStatement(Statement arg0) {
try {
// avoid self-cycles
if
(arg0.getSubject().stringValue().equals(arg0.getObject().stringValue()))
return;
sc.addStatement(arg0.getSubject(), arg0.getPredicate(),
arg0.getObject());
manager.incrCounter();
if (manager.atCommit())
System.out.print(.);
} catch (SailException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
System.out.println(Subject: +
arg0.getSubject().toString() +
Predicate: +
arg0.getPredicate().toString() +
Object: +
arg0.getObject().toString());
}
}
public void startRDF() throws RDFHandlerException {
}
public void endRDF() throws RDFHandlerException {
}
}
Cheers,
Shri
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Re: [Neo4j] Update/Move relationships through REST APIs
Hi,
I did you example over TinkerGraph as vertex IDs are Strings and thus, easy to
build your graph with.
~$ gremlin
\,,,/
(o o)
-oOOo-(_)-oOOo-
gremlin g = new TinkerGraph()
==tinkergraph[vertices:0 edges:0]
gremlin g.addVertex('A'); g.addVertex('B'); g.addVertex('C');
g.addVertex('D'); g.addVertex('E');
==v[E]
gremlin g.addEdge(g.v('C'),g.v('A'),'foo');
g.addEdge(g.v('D'),g.v('A'),'foo'); g.addEdge(g.v('E'),g.v('A'),'bar')
==e[2][E-bar-A]
gremlin g.V
==v[D]
==v[E]
==v[A]
==v[B]
==v[C]
gremlin g.E
==e[2][E-bar-A]
==e[1][D-foo-A]
==e[0][C-foo-A]
So, you have your 5 vertices and 3 edges. Next, here is your mutating traversal:
gremlin g.V.outE('foo').sideEffect{g.addEdge(it.outVertex,g.v('B'),'foo');
g.removeEdge(it)}
==e[1][D-foo-A]
==e[0][C-foo-A]
And now your edges are as you wanted them.
gremlin g.E
==e[3][D-foo-B]
==e[2][E-bar-A]
==e[4][C-foo-B]
So again, your traversal is:
g.V.outE('foo').sideEffect{g.addEdge(it.outVertex,g.v('B'),'foo');
g.removeEdge(it)}
Here is what the traversal says step-by-step:
g.V : iterate through all vertices
outE('foo') : iterate through their the outgoing 'foo' labeled edges
sideEffect{} : yield a sideEffect (mutate state)
g.addEdge(it.outVertex,g.v('B'),'foo'): add a new edge from the
vertex (e.g. C,D,E -- it.outVertex) to vertex B with label 'foo'.
g.removeEdge(it) : remove the current edge (it)
Note that its more optimal to do:
v = g.v('B');
g.V.outE('foo').sideEffect{g.addEdge(it.outVertex,v,'foo'); g.removeEdge(it)}
Also, vertex IDs are not Strings in Neo4j, but longs. Hopefully you can do what
you need from here.
Good luck,
Marko.
http://markorodriguez.com
On Aug 31, 2011, at 6:17 PM, Nuo Yan wrote:
I want to update the ending node for all relationships that are type :foo
coming into node A to node B.
For example, for all relationships that are type :foo coming into node A
(node A as the end node), no matter where their starting node is, I want
them to set the end node to node B.
Node C --:foo-- Node A
Node D --:foo-- Node A
Node E --:bar-- Node A
would become:
Node C --:foo-- Node B
Node D --:foo - Node B
Node E --:bar-- Node A
On Wed, Aug 31, 2011 at 5:00 PM, Marko Rodriguez okramma...@gmail.comwrote:
Hi,
If you tell me in English what you want to do, I can give you the Gremlin
query. With Gremlin, you can traverse and update in a single query so
perhaps it will meet your needs.
Marko.
http://markorodriguez.com
On Aug 31, 2011, at 5:13 PM, Nuo Yan wrote:
I looked through the REST APIs and didn't see an endpoint to move
relationships. Is such operation possible? For example, given a set of
relationships all end in one node, I want to send a bulk request to
update
their end nodes to another node.
If there is no REST API for updating/moving relationship, what is the
best
way to do this? Can gremlin do it easily? Or do I have to delete all of
the
relationships and create new ones to the new end node?
Thanks,
Nuo
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Re: [Neo4j] Update/Move relationships through REST APIs
Hey,
One more thing.
WARNING: If your transaction mode is AUTOMATIC, then there will be one
transaction for each mutation !! tx.begin/tx.commit/tx.finish
gremlin g.transactionMode
==AUTOMATIC
You can use a transaction manager if you plan this query to iterate over lots
of vertices and do lots of mutations:
https://github.com/tinkerpop/blueprints/wiki/Graph-Transactions-Helpers
Thus, your mutating traversal would be:
manager = TransactionalGraphHelper.createCommitManager(g, 1000);
g.V.outE('foo').sideEffect{g.addEdge(it.outVertex,g.v('B'),'foo');
g.removeEdge(it); manager.incrCounter()}
manager.close();
Hope that helps -- and doesn't confuse :).
Marko.
http://markorodriguez.com
P.S. Gremlin 1.3 will make it much more natural to do batch transactions.
TransactionGraphs (like Neo4j) will have a setTransactionBuffer(int
bufferSize) method so you don't need to create this CommitManager object.
Anywho. Thats that. See ya.
On Aug 31, 2011, at 7:38 PM, Marko Rodriguez wrote:
Hi,
I did you example over TinkerGraph as vertex IDs are Strings and thus, easy
to build your graph with.
~$ gremlin
\,,,/
(o o)
-oOOo-(_)-oOOo-
gremlin g = new TinkerGraph()
==tinkergraph[vertices:0 edges:0]
gremlin g.addVertex('A'); g.addVertex('B'); g.addVertex('C');
g.addVertex('D'); g.addVertex('E');
==v[E]
gremlin g.addEdge(g.v('C'),g.v('A'),'foo');
g.addEdge(g.v('D'),g.v('A'),'foo'); g.addEdge(g.v('E'),g.v('A'),'bar')
==e[2][E-bar-A]
gremlin g.V
==v[D]
==v[E]
==v[A]
==v[B]
==v[C]
gremlin g.E
==e[2][E-bar-A]
==e[1][D-foo-A]
==e[0][C-foo-A]
So, you have your 5 vertices and 3 edges. Next, here is your mutating
traversal:
gremlin g.V.outE('foo').sideEffect{g.addEdge(it.outVertex,g.v('B'),'foo');
g.removeEdge(it)}
==e[1][D-foo-A]
==e[0][C-foo-A]
And now your edges are as you wanted them.
gremlin g.E
==e[3][D-foo-B]
==e[2][E-bar-A]
==e[4][C-foo-B]
So again, your traversal is:
g.V.outE('foo').sideEffect{g.addEdge(it.outVertex,g.v('B'),'foo');
g.removeEdge(it)}
Here is what the traversal says step-by-step:
g.V : iterate through all vertices
outE('foo') : iterate through their the outgoing 'foo' labeled edges
sideEffect{} : yield a sideEffect (mutate state)
g.addEdge(it.outVertex,g.v('B'),'foo'): add a new edge from the
vertex (e.g. C,D,E -- it.outVertex) to vertex B with label 'foo'.
g.removeEdge(it) : remove the current edge (it)
Note that its more optimal to do:
v = g.v('B');
g.V.outE('foo').sideEffect{g.addEdge(it.outVertex,v,'foo'); g.removeEdge(it)}
Also, vertex IDs are not Strings in Neo4j, but longs. Hopefully you can do
what you need from here.
Good luck,
Marko.
http://markorodriguez.com
On Aug 31, 2011, at 6:17 PM, Nuo Yan wrote:
I want to update the ending node for all relationships that are type :foo
coming into node A to node B.
For example, for all relationships that are type :foo coming into node A
(node A as the end node), no matter where their starting node is, I want
them to set the end node to node B.
Node C --:foo-- Node A
Node D --:foo-- Node A
Node E --:bar-- Node A
would become:
Node C --:foo-- Node B
Node D --:foo - Node B
Node E --:bar-- Node A
On Wed, Aug 31, 2011 at 5:00 PM, Marko Rodriguez okramma...@gmail.comwrote:
Hi,
If you tell me in English what you want to do, I can give you the Gremlin
query. With Gremlin, you can traverse and update in a single query so
perhaps it will meet your needs.
Marko.
http://markorodriguez.com
On Aug 31, 2011, at 5:13 PM, Nuo Yan wrote:
I looked through the REST APIs and didn't see an endpoint to move
relationships. Is such operation possible? For example, given a set of
relationships all end in one node, I want to send a bulk request to
update
their end nodes to another node.
If there is no REST API for updating/moving relationship, what is the
best
way to do this? Can gremlin do it easily? Or do I have to delete all of
the
relationships and create new ones to the new end node?
Thanks,
Nuo
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Re: [Neo4j] REST API: output respresentation and performance
Hi,
- Data transfer bottleneck. Returning a large set of nodes/relationships
from a Gremlin query with Json might result in excesive result size. We
transfer from hundreds to 100.000 entities. In our case, we only need to
obtain a single property value (or just a few properties) for each
node/relationship. Is it possible to control/limit data in exported node
representation? We guess this would solve the problem.
Why return nodes/relationships if you only want a single property:
g.v(1).out.in.myProperty
- Server-side calculations. We find Gremlin very useful to perform simple
calculations on server side. However, we were not able to return Map result
generated by Gremlin's groupCount () call on entity property. The script
traverses multiple relationships and builds { propertyName, counter }
histogram. This works fine in Gremlin console, but how to export this result
back via REST API. We tried tables, but this option seems to be limited only
to nodes/relationships. Any options?
I don't know enough about the REST API and Gremlin, but have you tried:
m = [:]
g.v(1).my.groupCount(m).based.traversal -1
m
where you need the 'm' at the end to return the map.
Or are you saying that m can't be converted correctly to something Neo4j
managed extensions can understand and JSONify for you?
See ya,
Marko.
http://markorodriguez.com
Thanks for help in advance!
Best regards,
Oleg Morajko
innoquant.com
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Re: [Neo4j] RDF querying
Hello,
Note that with loadFile(), you are not incrementing your commit manager's
counter and thus, if your RDF file is large, you may run out of memory. See the
work of Claudio for a good model for large RDF graphs:
http://blog.acaro.org/entry/dbpedia4neo
https://github.com/claudiomartella/dbpedia4neo/tree/master/src/main/java/org/acaro/dbpedia4neo/inserter
Finally, you do not manager.close() at the end in order to commit your
transaction.
Good luck,
Marko.
http://markorodriguez.com
On Aug 28, 2011, at 9:09 AM, Shri :) wrote:
Hello everyone,
I am very very new to Neo4j and OOP, I am working on a project using
Neo4j system. I have already uploaded my RDF data into Neo4j using the
following code (snippet)
Neo4jGraph neo = new Neo4jGraph(dataset);
Sail sail = new GraphSail(neo);
sail.initialize();
CommitManager manager =
TransactionalGraphHelper.createCommitManager(neo, 10);
SailConnection sc= sail.getConnection();
for (String file: args) {
System.out.println(Loading + file + : );
loadFile(file, sail.getConnection(), sail.getValueFactory(), manager);
System.out.print('\n');
}
I now want to write write a separate code to make my connection with the
already created RDF store using Sail, I am confused about how I can make
this connection without creating any new store..Kindly throw some light on
this, I am stuck very badly..Thanks in advance..
shri
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Re: [Neo4j] A big graph for test
Hi, First, I analyze the statistics of my real-world graph data set. For example, determine the degree distribution -- if you want to get fancy, the degree distribution for each edge type/label. Then I plot that on a log/log-scale. Get the slope of that plot which gives me the alpha exponent. From there, I use iGraph, NetworkX, etc. to generate an artificial graph (at whatever size I want) that respects that scaling exponent (that alpha). Another method, that is easier is simply to do a rich-get-richer, preferential attachment algorithm which will give you a natural looking graph at any arbitrary size. The algorithm for that is fairly simple---max 50 lines of code. HTH, Marko. http://markorodriguez.com On Aug 8, 2011, at 9:53 AM, Michael Hunger wrote: Normally you just write a generator that creates nodes, relationships and properties that would resemble YOUR domain model. You can create a graph using that generator either with the normal java API or if it is really large (100M+ nodes and rels) then use the Batch-Inserter-API for that. Then you implement your use-cases on top of your domain model and test and verify them on a small graph and performance test them on the large, generated graph. Cheers Michael Am 08.08.2011 um 17:49 schrieb Reza Ameri: Hi, How can I test my application that uses Neo4j? I can not find a huge sample graph to test my app with it. Is there any one that can help me??? Thank you all ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] possible to query spatial indexes from gremlin?
Hey,
:).
You can do:
g.idx('test')[['bbox','[15.0, 16.0, 56.0, 61.0]']]
See ya,
Marko.
http://markorodriguez.com
On Aug 8, 2011, at 4:27 PM, Peter Neubauer wrote:
Boris,
I extended the functional tests to do what you are asking for,
https://github.com/neo4j/neo4j-spatial/blob/master/features/start-and-stop.feature
Basically:
Create a Spatial Layer
Add nodes
Load the index with provider=spatial configuration
Query it using Cypher
Query it using Gremlin
Query it using the REST index interface
Thus, you can now query the (trivial) point layer index using any of
your favorite methods. Is that helpful?
Cheers,
/peter neubauer
GTalk: neubauer.peter
Skype peter.neubauer
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LinkedIn http://www.linkedin.com/in/neubauer
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On Mon, Aug 8, 2011 at 3:31 PM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
Ahh ok.
In that case, I should extend the capabilities of the REST plugins and add a
test for it. Will see if I can get to it tonight, ok?
/peter
Sent from my phone.
On Aug 8, 2011 2:41 PM, Boris Kizelshteyn boris.kizelsht...@popcha.com
wrote:
Can I set this in the server config? I am doing everything via rest right
now, I am using the spatial plugin for doing the spatial operations.
On Mon, Aug 8, 2011 at 3:05 AM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
Boris, make sure that you have initialized the spatial index before
you access is. See
https://github.com/neo4j/neo4j-spatial/blob/master/src/test/java/org/neo4j/gis/spatial/IndexProviderTest.java#L68
for loading the index with provider=spatial. The index is loaded
lazy, and thus not available before explicitly loaded. I guess you
have to do it in your loading code in Java or Groovy, since you can't
provide the configuration in Gremlin or Cypher. After the first load,
the index will be saved in the database and be visible as any other
index. I haven't tried this out but it should work, as you see in the
test case.
Does that work?
Cheers,
/peter neubauer
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On Sun, Aug 7, 2011 at 11:11 PM, Boris Kizelshteyn bo...@popcha.com
wrote:
I'm doing it from the console.
On Sun, Aug 7, 2011 at 5:09 PM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
What is the surrounding code before that call? You gave to at least
once
get that index as in the test via the index provider parameters before
this
works.
/peter
Sent from my phone.
On Aug 7, 2011 10:25 PM, Boris Kizelshteyn bo...@popcha.com wrote:
Hi Peter,
I tried this today but I can't seem to get the syntax right in the
context
of g.idx, I tried this:
g.idx('spatial')[[start n=(mylayer,'bbox:[myvals]') match (n) -[r]
-
(x)
return n.bbox, r~TYPE, x.layer?, x.bbox?]]
But it does nothing, not even an error. So I am proly doing
something
terrible wrong? Also, I don't see the spatial index in the idx list
in
the
webpanel, I know I have one as I am able to query other spatial
info.
Thanks!
On Wed, Aug 3, 2011 at 12:48 PM, Peter Neubauer
peter.neuba...@neotechnology.com wrote:
Boris,
I was thinking of adding a test with Gremlin onto
https://github.com/neo4j/neo4j-spatial/blob/master/src/test/java/org/neo4j/gis/spatial/IndexProviderTest.java#L90
,
but basically, since recently a trivial point layer is exposed as
an
IndexProvider, enabling Neo4j, Cypher and Gremlin to treat this as
a
normal index. I have not tested it, but I suspect it works. Give
it
a
try and report back!
Cheers,
/peter neubauer
GTalk: neubauer.peter
Skype peter.neubauer
Phone +46 704 106975
LinkedIn http://www.linkedin.com/in/neubauer
Twitter http://twitter.com/peterneubauer
http://www.neo4j.org - Your high performance graph
database.
http://startupbootcamp.org/ - Öresund - Innovation happens HERE.
http://www.thoughtmade.com - Scandinavia's coolest Bring-a-Thing
party.
On Wed, Aug 3, 2011 at 9:36 AM, Boris Kizelshteyn
bo...@popcha.com
wrote:
how would you do a basic find point in layer type query?
Thanks!
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[Neo4j] [Blog Post] Mario Brothers! ... and Gremlin/Pipes stuff.
Hi, Before leaving for a 2.5 week vacation, I thought it would be good to drop another blog post. This will be my last post before I buckle down on a paper for GDM'12 ( http://www.cse.unsw.edu.au/~iwgdm/2012/ ) or die an excruciatingly painful death on my vacation. In this post we learn about Pipes and its fleeting relationship to Gremlin. http://markorodriguez.com/2011/08/03/on-the-nature-of-pipes/ I hope you find it enjoyable, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Property graph model vs. classical approach
Hey Norbert,
I'm wondering why Neo4j provides an API based on a property graph model and
is not using the classical graph approach GV,E?
What are the advantages of this architecture? Any thoughts? Is Neo4j
internally really based upon a property graph?
What are the disadvantages of a property graph?
The ordering of ease of modeling for binary graph data structures is in a
hierarchy like this:
G = (V,E \subseteq {V \times V}) (undirected graph)
G = (V, E \subseteq (V \times V)) (directed graph)
G = (V, E \subseteq (V \times V), \Omega: E - \Sigma)
(multi-relational graph)
G = (V, E \subseteq (V \times V), \Omega: E - \Sigma, P : (V \cup E)
- (\Sigma \times U) (property graph)
RDF is a multi-relational graph. The benefit of the multi-relational graph over
the property graph is that it more straightforward when it comes to modeling --
e.g. In property graph modeling, you tend to be confronted with this question:
Is this a property or another vertex?) at the expense of verbosity (How do I
model edge weight with a multi-relational graph?)
However, in theory, what you can express with a property graph, you can express
with an undirected graph.
http://arxiv.org/abs/0804.0277
Are you talking strictly in terms of expressivity in modeling, or other
compute physics oriented issues?
See ya,
Marko.
http://markorodriguez.com
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Re: [Neo4j] RDF Store Research
Hey, I have some questions for our research of possible RDF Triple Stores with fast graph traversal and fast (fulltext) search. As of now we are using OpenRDFs Native and Memory Stores and OpenLink Virtuoso as our RDF Triple Store. How is the performance compared to OpenRDF Native and Memory Store when using Tinkerpop Bluprints with there SAIL Ouplementation? Area there any experience, any benchmarks? We would also like to do have (fulltext) search in the graph data built in. Is Neo4J the right store for that? The beauty of the Sail Ouplementation model is that it is optimized for both index-based queries (spgo) and traversal-based queries. If you look at the technologies in OpenRDF, they are very index-based (SPARQL, getStatements(), etc.). While, with Blueprints GraphSail, you can use this API (implements Sail), you can also drop down into native Blueprints or Neo4j and thus, have a quad-RDF graph represented as a linked list structure and thus, do fast traversals. It is a bit of the best of both worlds in that sense... In terms of performance benchmarks, we don't have any right now as GraphSail is a recent addition to Blueprints and is still being heavily developed/optimized. Also, I believe AllegroGraph has a disk/memory representation these days that makes for fast traversals (used in their SNA package) so you might want to check them out. Also, see StarDog which is a full Java-based RDF quadstore ( http://stardog.com/ ) which has Gremlin as their distributed path-based language. Finally, most RDF stores provide full text search. Moreover, Neo4j does as well. See ya, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Property graph model vs. classical approach
Yo, I'm simply confronted with the question 'why do you use such a graph model and not another one based on graph classes'? Hence, I'm gathering pros and cons for the 'property graph' model. Why is an interface like the one of Neo4j provided this way and not in another (e.g. using graph classes). Is there any design or architectural decision we don't know, yet? The longer I think the more I come to the conclusion that important points are: object-oriented representation of a network, and related with that, an 'external' representation of the graph structure that is not bound to a graph class managing the access to the graph structure and the data stored in properties. All other points like performance, or representation of the graph structure, seem to be equivalent to text-book graphs (directed, undirected, etc.), like you already stated out. Ah. I remember now -- you are interested in vertex typing (classes). I read your paper on the topic. Here are my thoughts on the matter. In the world of RDF (which is has nice clear separations), there is the data model (multi-relational graph), the schema language (RDF schema), and the ontology language (OWL). Mixing these layers into a single framework is deadly because you pigeonhole the interpretation of the graph. For example, if you are into classes and type hierarchies (and OO-based instantiations), then you are pigeonholing yourself into close-world semantics and a taxonomical mind-set. Thats great for you if you like that sort of thing---but what about others who wish, lets say to explore evidential logics in which such strongly typed models are not desired. This is also one of my problems with the RDF stack---while keeping the layers separate, RDF/RDFS/OWL is seen as the only layer. And frankly, description logics are not the only useful logics ( http://arxiv.org/abs/0905.3378 ). Now map that to what you are saying about property graphs and vertex typing. A property graph is a multi-relational graph data model. You can build logic layers atop to implement your worldview as you see fit. It is the job of the database to persist the structure and make it fast to traverse/query. It is the job of the layers above to model and create meaning. Perhaps it is also a problem that the term 'property graph' isn't formally declared in some kind of scientific work and therefore widely unknown, isn't it? Science is an industry claiming to be the ruler by which ideas are measured. Ideas do not need science. However, science needs ideas. Do not be sucked into the trap -- you will end up wearing a dusty suit, unhealthy, in some stodgy dinning hall at some conference talking to others who think publications make truth. And worst of all, you will be wearing a name tag. Outz, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Collaborative filtering in Cypher
Hi,
Hi, I'm new to graph databases and have been trying to understand the power
of Cypher and/or Gremlin as a way to develop suggestion queries. I've
watched a few webinars and read through some of the documentation but I've
had a hard time figuring out complex suggestion type queries other than
stuff like find me the top 3 movies my friends have recommended, or given
that I rated this movie 5 stars, find me other people who liked this movie.
This is a common query that looks something like this in Gremlin.
m = [:] // create final rankings map
g.v(1).outE('rated'}{it.stars == 5}.inV.inE('rated'}{it.stars ==
5}.outV.outE('rated'){it.stars == 5}.inV.groupCount(m)
The last line says:
v.outE('rated'}{it.stars == 5}.inV // what movies do I like (5 stars)
assuming you are g.v(1)
.inV.inE('rated'}{it.stars == 5}.outV // who else really likes those
moves (5 stars)
.outE('rated'){it.stars == 5}.inV.groupCount(m) // what else do they
really like
You can do some stuff with aggregate() and except() if you want to filter out
those movies in m that you have already seen.
You can do some wicked stuff like this with Gremlin 1.2 (just released):
m = [:] // create final rankings map
g.v(1).outE('rated'}{it.stars == 5}.inV.inE('rated'}{it.stars ==
5}.outV.outE('rated'){it.stars
3}.sideEffect{x=it.stars}.inV.groupCount(m){it.name}{it + x}
In the above, you are saying which movies do they like ( 3 -- not necessarily
love, but just like), and then use that value (the stars) as the value you put
into the ranking map (see the key/value closures off of groupCount(), where it
is the previous value of that particular key). With respect to your weighting
stuff you want to do below in your email, stuff like that comes in handy.
To give a simplified example of what I'm trying to achieve is something like
suggesting users based on attributes they weight from 0-1 and those
attributes can have relationships between each other and I want to find
something like the Tanimoto coefficient but weights as opposed to strictly
binary attributes or slope one for a start user to end users and then list
the top X. I have the O'Reilly book on Collective Intelligence but I've only
seen examples for set theory, not for graph theory.
I was thinking of Something like:
UserA likes Digital Photography with a weight of 1
UserA likes Wine with a weight of .8
UserA likes Rock music with a weight of 1
UserB likes Film Photography with a weight of 1
UserB likes Rock music with a weight of .5
UserB likes Beer with a weight of 1
Digital Photography is related to Film Photography with a weight of .5
I want to return how alike these two users are. I understand the graph
theory behind it in that I want to follow all likes relationships and is
related relationships till I hit another user and then with those paths that
I have to that user I want to multiply the weights of the relationships
along that path to get a score and then add those scores to get a final
score.
So in the above example it would look something like:
UserA-Digital Photography-Film Photography-UserB = 1 * .5 * 1 = .5
UserA-Rock-UserB = 1 * .5 = .5
Final tally = 1.
I didn't read the above. Got lazy.
And then if there were mere users it would follow the paths to find those
users as well and find the scores and then sort the users by score. Looking
at Gremlin and Cypher, I'm not sure where to even start to work on query
that can do this and if it even is possible.
Just bust a paths() step at the end:
g.v(1).outE('rated'}{it.stars == 5}.inV.inE('rated'}{it.stars ==
5}.outV.outE('rated'){it.stars == 5}.inV.groupCount(m).paths
That is the path from you to the movies that are recommended to you. You can do
path closures in Gremlin 1.2 so you can yield computations on the path
elements, but I won't get into that. See the Gremlin documentation and
examples. http://gremlin.tinkerpop.com
I know what I described isn't slope one or the Tanimoto coefficient because
it doesn't take into account the full set of attributes for the second user,
but I'm just getting used to this and right now my potential solution is
just have all unrelated attributes have edges of weight 0, but yeah I'm
probably getting ahead of myself. I'm just looking for a point in the right
direction for places to research and perhaps if they're available see some
actual Cypher queries that have done weighted suggestions based on
attributes.
I didn't read everything you wrote, so if what I provided isn't sufficient,
please ask a particular question, and preferably not at great length.
WARNING: All Gremlin examples were typed into the email. You may have to fiddle
as I might have missed a ( { ' and as such, might be bugged.
Thanks,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Brainstorming on my project: neo4john
Marko had a good line about this: graphs are adjacency free indexes (or words to that affect). :) -- Index-free Adjacency Marko. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Neo4J Gremlin Query for dates
Hi,
I have dates in Neo4j stored as JSON Dates.
e.g.
DateCreated: /Date(1310360656147+)/
LastLogin: /Date(1311927251851+)/
I use the iterator and lambda way of query data
e.g.
g.v(0).outE[[label:'HOSTS']].inV{it.'Name'.compareTo('Agency1') == 0}.Name
SIDENOTE: g.v(0).out('HOSTS'){ } is a more concise and speedier
representation.
However I want to compare dates, what is the format we can use for this?
Currently we have written a .Net client to consume Neo4J and I we have a
formatter in the client api that converts c# lambda's to java lambda's, so it
would be nice to know the best way to do date comparisons :)
e.g.
g.v(0).outE[[label:'HOSTS']].inV{it.'LastLogin'.dateCompareTo('/Date(1311927251851+)/')
== 0}.Name
Huh. I would use Java/Groovy Date object. ? ...
http://www.cafeaulait.org/course/week4/68.html
DateFormat formatter = new SimpleDateFormat(MMdd);
Date rootDate = formatter.parse(dateString);
Thus, something like:
g.v(0).out('HOSTS'){formatter.parse(it.LastLogin).after(rootDate)}.Name
HTH,
Marko.
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Re: [Neo4j] Comparing properties among different nodes in Gremlin
Jump out from behind bushes/
Hey hey,
Thank you again, Marko. Let's try with a query that I'm not able to
build in Gremlin. Looking at the property graph, I need the final
vertices of all the paths of length 3, with at least one property
name equals to josh in some vertex except the first one.
Here is the concise pro-style, where 'both' traverses both incoming and
outgoing adjacent vertices.
g.V.both.loop(1){it.loops 4}[[name:'josh']]
Here is the less than pro-style (as('x') is a way to name a step so its more
readable where to loop back to):
g.V.as('x').both.loop('x'){it.loops 4}[[name:'josh']]
This will give you the actual paths with, of course, the last element in the
path being the vertex with name 'josh' (v[4]).
g.V.both.loop(1){it.loops 4}[[name:'josh']].paths
Finally, realize that you might incur reverberation in your paths.
gremlin g.V.both.loop(1){it.loops 4}[[name:'josh']].paths
==[v[3], v[1], v[3], v[4]] // reverb
==[v[3], v[4], v[1], v[4]] // reverb
==[v[3], v[4], v[5], v[4]] // reverb
==[v[3], v[4], v[3], v[4]] // reverb
==[v[3], v[6], v[3], v[4]] // reverb
==[v[2], v[1], v[3], v[4]]
==[v[1], v[2], v[1], v[4]] // reverb
==[v[1], v[3], v[1], v[4]] // reverb
==[v[1], v[4], v[1], v[4]] // reverb
==[v[1], v[4], v[5], v[4]] // reverb
==[v[1], v[4], v[3], v[4]] // reverb
==[v[6], v[3], v[1], v[4]]
==[v[5], v[4], v[1], v[4]] // reverb
==[v[5], v[4], v[5], v[4]] // reverb
==[v[5], v[4], v[3], v[4]] // reverb
==[v[4], v[1], v[3], v[4]] // reverb
==[v[4], v[3], v[1], v[4]] // reverb
As such you can use uniquePath to remove reverberant paths:
gremlin g.V.both.loop(1){it.loops 4}[[name:'josh']].uniquePath
==v[4]
==v[4]
gremlin g.V.both.loop(1){it.loops 4}[[name:'josh']].uniquePath.paths
==[v[2], v[1], v[3], v[4]]
==[v[6], v[3], v[1], v[4]]
Hope that helps,
Marko.
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Re: [Neo4j] Comparing properties among different nodes in Gremlin
Hi,
I mean, I need to compare the value of a node property with the value
in the last node property, and repeat the process on every node to
check growth rates. But I don't if this is possible without using
variables external to the query.
I don't know if this is your paricular solution, but I do this all the time:
g = Tinkegremlin g = TinkerGraphFactory.createTinkerGraph()
==tinkergraph[vertices:6 edges:6]
gremlin g.v(1).sideEffect{x = it.name}.out.sideEffect{println x}
marko
==v[2]
marko
==v[3]
marko
==v[4]
gremlin
In other words, I use a sideEffect to save something to 'x' and then later can
access that x for something -- in this limp example, simply to
System.out.println it.
Does that help you? Can you map that motif over to your problem?
Good luck,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Comparing properties among different nodes in Gremlin
Hi,
Does that help you? Can you map that motif over to your problem?
Thank you, I hope so. Maybe the best way is to get all the properties
map in each vertex in order to be able to operate with those values in
the next vertex. Is that possible?
In that case do:
gremlin g.V.sideEffect{x = it.map()}.out.sideEffect{println x}
[name:marko, age:29]
==v[2]
[name:marko, age:29]
==v[3]
[name:marko, age:29]
==v[4]
[name:peter, age:35]
==v[3]
[name:josh, age:32]
==v[5]
[name:josh, age:32]
==v[3]
In short, every vertex out of V is passed into sideEffect{}. The current
vertex's properties are saved to x as a HashMap. Then the outgoing related
vertices of that vertex are retrieved. There is a sideEffect again where you
can access your map in x from previous.
Perhaps I'm misunderstanding your use case... Finally, you might want to
consider aggregate as a way to get all before processing the next step. Check
this:
gremlin x = []
gremlin g.V.aggregate(x).out.sideEffect{println x*.map()}
[[name:lop, lang:java], [name:vadas, age:27], [name:marko, age:29],
[name:peter, age:35], [name:ripple, lang:java], [name:josh, age:32]]
==v[2]
[[name:lop, lang:java], [name:vadas, age:27], [name:marko, age:29],
[name:peter, age:35], [name:ripple, lang:java], [name:josh, age:32]]
==v[3]
[[name:lop, lang:java], [name:vadas, age:27], [name:marko, age:29],
[name:peter, age:35], [name:ripple, lang:java], [name:josh, age:32]]
==v[4]
[[name:lop, lang:java], [name:vadas, age:27], [name:marko, age:29],
[name:peter, age:35], [name:ripple, lang:java], [name:josh, age:32]]
==v[3]
[[name:lop, lang:java], [name:vadas, age:27], [name:marko, age:29],
[name:peter, age:35], [name:ripple, lang:java], [name:josh, age:32]]
==v[5]
[[name:lop, lang:java], [name:vadas, age:27], [name:marko, age:29],
[name:peter, age:35], [name:ripple, lang:java], [name:josh, age:32]]
==v[3]
In this way, x has ALL the maps of all the vertices coming out of V. x is an
ArrayListHashMap(). You can then do some sideEffect work on that aggregation
later in the path expression... Does that help?
My use case is a little particular. I'm writing a mini language to
support ITL [1], which can work over Kripke structures [2] stored in a
graph. So what I'm doing is a lexer and a grammar to translate ITL
into Gremlin queries.
Ah. You might wish to translate it directly to Pipes perhaps? In one week
(August 1st -- next round of TinkerPop releases), Pipes++ is coming out which
will make it very easy for anyone to emulate Gremlin behavior in any language
of their choosing.
http://groups.google.com/group/gremlin-users/browse_thread/thread/a1a7092762d22e37
Just a thought...
See ya,
Marko.
http://markorodriguez.com
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Re: [Neo4j] Comparing properties among different nodes in Gremlin
Hi, Pipes++ looks interesting. I have to do more tests but I hope to find a way to acomplish my goal. I will give you any query you ask over the play dataset: https://github.com/tinkerpop/gremlin/wiki/Defining-a-Property-Graph Thus, if you say, Marko, tell me how to get all X, where Y, and this, but then ensure that, etc. etc., I will provide you the respective Gremlin expression. In this way, hopefully, you can then take that and map it to your particular problem domain. Hope all goes well with your project, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] paging
Hi, For Cypher, there is SKIP and LIMIT, together acting as a kind of paging system, but executing the query again (just giving you a different chunk of the result), so I am not sure that works for your case. http://docs.neo4j.org/chunked/snapshot/cypher-query-lang.html. Gremlin supports similar things. One thing to realize about paging in Gremlin is that due to Pipes/Gremlin's lazy nature, there is no notion of jump to cursor. For example: g.v(1).out[5..10] will iterate/compute/evaluate/traverse the objects 0 through 4. Just a heads up, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin performance?
Hey, Groovy is only used to compile a statement like g.v(1).out.in.blah to a Pipes which is native Java. As such, once the compilation is complete (milliseconds), it is simply native Java (This is not completely true as there are some Gremlin specific pipes). Next, for the relationship between Blueprints Neo4jGraph and native EmbeddedGraphDatabase, see this from some time ago: http://groups.google.com/group/gremlin-users/msg/c94dfef8352f68d3 In short, traversing 29.6 million things took: 5.6 seconds via EmbeddedGraphDatabase 6.0 seconds via Neo4jGraph ** As a side, the same experiment was run for OrientDB with a 7.2 (native OrientDB) vs. 7.9 (Blueprints OrientGraph). http://groups.google.com/group/gremlin-users/msg/ff5c03e188efcffe There is more discussion in that particular thread if you are interested. Finally, with respect to production, I have many clients that use Gremlin in production. Here are the benefits of do so: 1. Traversal descriptions are concise and expressive. - any arbitrary graph computation can be represented and evaluated. - in language theoretic terms, it can recognize Turing complete paths. 2. Traversal descriptions can be expressed as classes in Groovy and thus, IDE friendly. - syntax highlighting, easy to write test cases/debug, etc. - See slides 234 and 235 from http://www.slideshare.net/slidarko/the-pathology-of-graph-databases Thanks, Marko. http://markorodriguez.com On Jul 23, 2011, at 2:30 AM, Michael Hunger wrote: If you look at the comments of the post - groovy is only that slow if you implement all the algorithm details in groovy ! Gremlin uses blueprints which is written in Java. Gremlin is just a DSL on top of that API so it is just used for the construction of the underlying pipeline. Anyway, easiest way to see if that holds true is to write a PoC for _your_ domain, I think general statements are difficult. But probably Marko has some nice performance benchmarks at hand. Michael Am 23.07.2011 um 09:51 schrieb Josef Holy: Hi all, has someone on this list any practical experience with using Gremlin for traversing the EmbeddedGraphDatabase in a production environment? What interests me is how it performs compared to the traversal algorithms written directly against Neo4j APIs (using Traverser, TraversalDescription, ..etc). As Gremlin runs on top of Groovy + Pipes + Blueprints, I would expect it to be much slower than pure Neo4j Java APIs (but really SO much slower? http://stronglytypedblog.blogspot.com/2009/07/java-vs-scala-vs-groovy-performance.html ) . Thanks for any comments/experiences! Josef. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Gremlin performance?
Hi, Finally, one point to add. If I only need to do a ShorestPath over a particular edge type or a find all paths between two vertices and I'm using Neo4j as the graph backend, then I will drop down and use Neo4j's Algo library. This is because their ShorestPath implementation is bi-directional (efficient) and I would have to write that in Gremlin as Gremlin doesn't provide out of the box textbook algorithm support. TinkerPop plans an algo library for standard graph algorithms whose paths are defined by Pipes/Gremlin, but as of yet, it doesn't exist. See http://markorodriguez.com/2011/02/08/property-graph-algorithms/ Thanks, Marko. http://markorodriguez.com On Jul 23, 2011, at 9:16 AM, Marko Rodriguez wrote: Hey, Groovy is only used to compile a statement like g.v(1).out.in.blah to a Pipes which is native Java. As such, once the compilation is complete (milliseconds), it is simply native Java (This is not completely true as there are some Gremlin specific pipes). Next, for the relationship between Blueprints Neo4jGraph and native EmbeddedGraphDatabase, see this from some time ago: http://groups.google.com/group/gremlin-users/msg/c94dfef8352f68d3 In short, traversing 29.6 million things took: 5.6 seconds via EmbeddedGraphDatabase 6.0 seconds via Neo4jGraph ** As a side, the same experiment was run for OrientDB with a 7.2 (native OrientDB) vs. 7.9 (Blueprints OrientGraph). http://groups.google.com/group/gremlin-users/msg/ff5c03e188efcffe There is more discussion in that particular thread if you are interested. Finally, with respect to production, I have many clients that use Gremlin in production. Here are the benefits of do so: 1. Traversal descriptions are concise and expressive. - any arbitrary graph computation can be represented and evaluated. - in language theoretic terms, it can recognize Turing complete paths. 2. Traversal descriptions can be expressed as classes in Groovy and thus, IDE friendly. - syntax highlighting, easy to write test cases/debug, etc. - See slides 234 and 235 from http://www.slideshare.net/slidarko/the-pathology-of-graph-databases Thanks, Marko. http://markorodriguez.com On Jul 23, 2011, at 2:30 AM, Michael Hunger wrote: If you look at the comments of the post - groovy is only that slow if you implement all the algorithm details in groovy ! Gremlin uses blueprints which is written in Java. Gremlin is just a DSL on top of that API so it is just used for the construction of the underlying pipeline. Anyway, easiest way to see if that holds true is to write a PoC for _your_ domain, I think general statements are difficult. But probably Marko has some nice performance benchmarks at hand. Michael Am 23.07.2011 um 09:51 schrieb Josef Holy: Hi all, has someone on this list any practical experience with using Gremlin for traversing the EmbeddedGraphDatabase in a production environment? What interests me is how it performs compared to the traversal algorithms written directly against Neo4j APIs (using Traverser, TraversalDescription, ..etc). As Gremlin runs on top of Groovy + Pipes + Blueprints, I would expect it to be much slower than pure Neo4j Java APIs (but really SO much slower? http://stronglytypedblog.blogspot.com/2009/07/java-vs-scala-vs-groovy-performance.html ) . Thanks for any comments/experiences! Josef. ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Cypher request with where clause on relations count
Hey, Request is working like a charm and is fast (around 6 objects are checked in my 2M node 6M rel DB). I have to check the result with the corresponding RDBMS KPI. Nice. Thanks again ! No problem. I definitively have to take more time to learn Gremlin ! You are more than welcome to always ask questions on the Gremlin-users mailing list. http://groups.google.com/group/gremlin-users Or, if you prefer, I'm here too.. and right behind you as well. insert scream/ Have fun, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] retrieve all relationships of a certain type (java)
Hey, How would I go about retrieving all nodes for a certain relationship Type (ie. assuming I don't know any of them nodes) ? Use an index. I don't know in native Neo4j off the top of my head, but the analogous to this in Blueprints: g.getIndex(edges, Edge.class).get(label,myType) Indices allow you to group edges of similar label together. See ya, Marko. http://markorodriguez.com On Jul 20, 2011, at 12:54 PM, cyuczi eekc wrote: (in java code, the other variants rest/cypher I will probably not need to use) ie. rel.getAllNodes(Direction.INCOMING) or rel.getAllNodes(Direction.OUTGOING) or Direction.BOTH even But this is basically equivalent with retrieving all relationships that are of the specified relationship-type. So this would be more accurate: rel.getAllRelationships(); where rel is the Relationship of the type that we want and the getAllRelationships() would return something that would be a list of all relationship of that type (in the entire database I guess) but possibly _*without*_ having to iterate (or traverse?) all nodes(i guess starting from the reference node?), in order to find if each has the relationship type I'm looking for. (I haven't yet fully looked at traverse but I know it needs a starting node, even though this could probably be the reference node[?]; this makes me wonder if there's a traverser for relationships instead of just nodes - I am unsure where to look [maybe just pointing me there would be enough of a reply to this; thanks]) The way I see it, the fact that relationships have a type is an extra layer on top of the relationships (just as indexing is extra(independent) layer on top of nodes or relationships). So I see the relationships each being unique (especially since I can add the same-type relationship to the same two nodes, more than 1 time) and they are somehow coalesced together via the relationship-type. It's like the relationship-type is a set which contains a bunch of relationships (which are obviously unique ie. unique ID) and this set constitutes a relationship-type. So since it's a set (probably stored as key-value pairs on the low level) one could potentially just get the elements via an iterator or something (but I also want to know how many aka size or count, relationships are there, of this type). (what I find a bit odd though, is that you can have more than one relationship for the same two nodes (1: A-B ; 2: A-B ), although dwins(on irc) implied that this is allowed because each relationship can have key-value pairs(properties) associated with it, and thus one could use same key for each relationship but with different values, but the practicality for this escapes me) ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Cypher request with where clause on relations count
Hey, @Marko thanks. I just tried to do it with Gremlin but I have not your knowledge of gremlin. I will try to do that. If you use Neo4j Server 1.4, then you will be in Gremlin 1.1 land. I don't know what you are rolling with (embedded, server, etc.), but if you want the query in Gremlin 1.1, just ask. Good luck, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Cypher request with where clause on relations count
@Marko I am using neo4j 1.4 server so I guess I am running gremlin 1.1.
It would be cool if you can send me the compatible query when you have time.
Good, cause time is all I have.
m = [:]
g.idx('id')[[object_type:'A']].transform{it.out('USES'){it.object_type.equals('B')}.count()
1}.groupCount(m) -1
m
Here is what it says section by section:
0. m = [:]: create a hashmap (your results)
1. g
- the graph
2. idx('id')[[object_type:'A']]
- hit the 'id' index for all vertices indexed with object_type
equal to 'A'
3. transform{it.out('USES'){it.object_type.equals('B')}.count() 1}
- for each of those A-vertices, emit true if the number of
times it connects to a B object by USES is than 1, else emit false.
4. groupCount(m)
- count the number of trues and falses and stores the counts in
the map m.
5. -1
- while(hasNext()) next() the pipeline expression
(http://pipes.tinkerpop.com if you are interested by what a pipeline is)
6. m
- return the map of counts.
Further diving into the transform{} step. The transform{} step takes an object
(in your case, a vertex), does some computation, and emits an object (in your
case, ...count() 1):
it.out('USES'){it.object_type.equals('B')}.count()
- it is the current vertex.
- get the vertices adjacent to it that are connected by USES
edges (outgoing connections only -- use both('USES') for both in and out)
- filter to only those objects whose object_type is 'B'
- count the number of B-vertices traversed to.
Or for more human readable keys:
m = [:]
g.idx('id')[[object_type:'A']].transform{if(it.out('USES'){it.object_type.equals('B')}.count()
1) count = 1 else count 1}.groupCount(m) -1
m
Also, you can view this like this, if it helps:
m = [:]
g.idx('id')[[object_type:'A']].transform{
if(it.out('USES'){it.object_type.equals('B')}.count() 1)
count = 1
else
count 1
}.groupCount(m) -1
m
This is all typed out in email so you might need to fiddle if I missed some ( {
' etc.
Finally, there is a slight optimization if you want it to run a few
milliseconds faster at the expense of more verbosity.
it.object_type.equals('B') is slower than
it.getProperty('object_type').equals('B')
Tell me how it goes:
Marko.
http://markorodriguez.com
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Re: [Neo4j] Getting sorted results from a traversal
Hi Pere,
To sort you need to have all your results.
Thus, in Gremlin (and hopefully you can do the mapping to the core Neo4j
traverser framework),
results = []
g.v(1).out('friend').out('likes') results // what my friends like
results.sort{a,b - a.name = b.name} // sort resultant vertices by name
In short, once you have the result of your traversal, you can then apply a
comparator to the Collection to sort it as you please --- its just Java
comparators.
See ya,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 8:06 AM, Pere Urbon Bayes wrote:
HI!
I am on the situation of having to traverse neo4j, and then expect the
resultset returned to be ordered in a certain order. I've been researching a
bit over the traversal API, but I did not find anything related to that. I
really will appreciate any tip on that!!
BTW I expect to be possible right?, as we have in relational the ordering,
or on redis, etc...
/purbon
--
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moviepilot GmbH | Mehringdamm 33 | 10961 Berlin | Germany
Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
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Re: [Neo4j] Getting sorted results from a traversal
Hi,
Ah. Then I would recommend using a persistent data structure such as the one
the Neil discussed in his follow up post.
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 9:04 AM, Pere Urbon Bayes wrote:
Well, this is great if I want to do all the math in memory, but I expect to
do the computation by the db.
/ purbon
On 15 July 2011 16:10, Marko Rodriguez okramma...@gmail.com wrote:
Hi Pere,
To sort you need to have all your results.
Thus, in Gremlin (and hopefully you can do the mapping to the core Neo4j
traverser framework),
results = []
g.v(1).out('friend').out('likes') results // what my friends like
results.sort{a,b - a.name = b.name} // sort resultant vertices by name
In short, once you have the result of your traversal, you can then apply a
comparator to the Collection to sort it as you please --- its just Java
comparators.
See ya,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 8:06 AM, Pere Urbon Bayes wrote:
HI!
I am on the situation of having to traverse neo4j, and then expect the
resultset returned to be ordered in a certain order. I've been
researching a
bit over the traversal API, but I did not find anything related to that.
I
really will appreciate any tip on that!!
BTW I expect to be possible right?, as we have in relational the
ordering,
or on redis, etc...
/purbon
--
Pere Urbon-Bayes
moviepilot GmbH | Mehringdamm 33 | 10961 Berlin | Germany
Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
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Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
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Re: [Neo4j] [Blog Post] Graphs, Brains, and Gremlin
Hi Rick, Added a comment and a book recommendation to your blog. Thanks. On Intelligence is the first reference in the references section of the post --- along with some other goodies. Thanks for reading and commenting, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] [Blog Post] Graphs, Brains, and Gremlin
Nice. It's a very though provoking (pun clearly intended) blog post. I need to read it a couple times to fully grok it. I put many links to associated reading (primarily on Wikipedia). If you don't have experience with elementary cognitive neuroscience, then you can learn all you need to know by following the links. I can save you 2-years of tuition: read the blog post and the one-step away Wikipedia pages :)...and if you want a graduate-level understanding of cognitive neuroscience, go two-steps. If you want to understand even more, do a spreading activation through Wikipedia :). Also, the HMAX diagram... http://markorodriguez.files.wordpress.com/2011/07/hmax-model.png ...is an accurate diagram and if you can follow what its trying to represent, then it will give you a good understanding of the first layers of the visual cortex are doing. Part of my postdoctoral work was on this model which is a computational model of the visual cortex that is biologically realistic. Its a very cool model indeed. I have two references in the references section that point to further HMAX information. Thanks again, Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Getting sorted results from a traversal
Hi,
Pere, my last thought on this is that you might want to use something like
JDBM2.
http://code.google.com/p/jdbm2/
It has a Maven2 dependency if you do it that way.
JDBM2 provides you some Java collection implementations that are persistent to
disk...
See ya,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 12:22 PM, Pere Urbon Bayes wrote:
Yeah! well to order in memory I can really deal with that task, for this I
really don't need cypher. Don´t take it personally, I know you really want
to promote your language, xD!
- purbon
PD: See you next graphdb meetup in Berlin!
On 15 July 2011 19:37, Michael Hunger michael.hun...@neotechnology.comwrote:
You might also try to use cypher for your traversal which is able to order
(also in memory of course).
See the screencast I did:
http://neo4j.vidcaster.com/U2Y/introduction-to-cypher/
It's even the same domain.
Cheers
Michael
Am 15.07.2011 um 17:24 schrieb Rick Bullotta:
But you couldn't easy do a complex traversal with an RDBMS. ;-)
I suspect that even if you could write some magic SQL to do so, you'd
almost certainly lose the benefits any optimized sorting/ordering that
indices provide, so even the RDBMS would have to post-process the sort.
If the traversal isn't complex or randomly deep, then Neo indexing +
querying might work for you the same way an RDBMS might handle it.
-Original Message-
From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org]
On Behalf Of Pere Urbon Bayes
Sent: Friday, July 15, 2011 11:21 AM
To: Neo4j user discussions
Subject: Re: [Neo4j] Getting sorted results from a traversal
Well, the thing is that the database can easy deal with that, as the
relational system do.
/ purbon
On 15 July 2011 17:08, Rick Bullotta rick.bullo...@thingworx.com
wrote:
The DB would do it in memory too, wouldn't it? In the case of a complex
traversal, indexes don't really apply, since the ordering and the
traversal
order are unrelated, so you'd generally need to sort in memory anyway.
Whether you do it as you add elements to the traversed list of stuff
or
do it after the fact is another discussion, but I think in either case,
it
needs to be done after the fact.
-Original Message-
From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org
]
On Behalf Of Pere Urbon Bayes
Sent: Friday, July 15, 2011 11:05 AM
To: Neo4j user discussions
Subject: Re: [Neo4j] Getting sorted results from a traversal
Well, this is great if I want to do all the math in memory, but I expect
to
do the computation by the db.
/ purbon
On 15 July 2011 16:10, Marko Rodriguez okramma...@gmail.com wrote:
Hi Pere,
To sort you need to have all your results.
Thus, in Gremlin (and hopefully you can do the mapping to the core
Neo4j
traverser framework),
results = []
g.v(1).out('friend').out('likes') results // what my friends like
results.sort{a,b - a.name = b.name} // sort resultant vertices by
name
In short, once you have the result of your traversal, you can then
apply
a
comparator to the Collection to sort it as you please --- its just Java
comparators.
See ya,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 8:06 AM, Pere Urbon Bayes wrote:
HI!
I am on the situation of having to traverse neo4j, and then expect the
resultset returned to be ordered in a certain order. I've been
researching a
bit over the traversal API, but I did not find anything related to
that.
I
really will appreciate any tip on that!!
BTW I expect to be possible right?, as we have in relational the
ordering,
or on redis, etc...
/purbon
--
Pere Urbon-Bayes
moviepilot GmbH | Mehringdamm 33 | 10961 Berlin | Germany
Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
___
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Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
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Re: [Neo4j] Getting sorted results from a traversal
Hey,
Actually, I was just Googling and found this cool library:
http://code.google.com/p/pcollections/
This way you have Set, Vector, etc. persisted. Perhaps that could help you out
Pere.
See ya,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 12:30 PM, Marko Rodriguez wrote:
Hi,
Pere, my last thought on this is that you might want to use something like
JDBM2.
http://code.google.com/p/jdbm2/
It has a Maven2 dependency if you do it that way.
JDBM2 provides you some Java collection implementations that are persistent
to disk...
See ya,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 12:22 PM, Pere Urbon Bayes wrote:
Yeah! well to order in memory I can really deal with that task, for this I
really don't need cypher. Don´t take it personally, I know you really want
to promote your language, xD!
- purbon
PD: See you next graphdb meetup in Berlin!
On 15 July 2011 19:37, Michael Hunger
michael.hun...@neotechnology.comwrote:
You might also try to use cypher for your traversal which is able to order
(also in memory of course).
See the screencast I did:
http://neo4j.vidcaster.com/U2Y/introduction-to-cypher/
It's even the same domain.
Cheers
Michael
Am 15.07.2011 um 17:24 schrieb Rick Bullotta:
But you couldn't easy do a complex traversal with an RDBMS. ;-)
I suspect that even if you could write some magic SQL to do so, you'd
almost certainly lose the benefits any optimized sorting/ordering that
indices provide, so even the RDBMS would have to post-process the sort.
If the traversal isn't complex or randomly deep, then Neo indexing +
querying might work for you the same way an RDBMS might handle it.
-Original Message-
From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org]
On Behalf Of Pere Urbon Bayes
Sent: Friday, July 15, 2011 11:21 AM
To: Neo4j user discussions
Subject: Re: [Neo4j] Getting sorted results from a traversal
Well, the thing is that the database can easy deal with that, as the
relational system do.
/ purbon
On 15 July 2011 17:08, Rick Bullotta rick.bullo...@thingworx.com
wrote:
The DB would do it in memory too, wouldn't it? In the case of a complex
traversal, indexes don't really apply, since the ordering and the
traversal
order are unrelated, so you'd generally need to sort in memory anyway.
Whether you do it as you add elements to the traversed list of stuff
or
do it after the fact is another discussion, but I think in either case,
it
needs to be done after the fact.
-Original Message-
From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org
]
On Behalf Of Pere Urbon Bayes
Sent: Friday, July 15, 2011 11:05 AM
To: Neo4j user discussions
Subject: Re: [Neo4j] Getting sorted results from a traversal
Well, this is great if I want to do all the math in memory, but I expect
to
do the computation by the db.
/ purbon
On 15 July 2011 16:10, Marko Rodriguez okramma...@gmail.com wrote:
Hi Pere,
To sort you need to have all your results.
Thus, in Gremlin (and hopefully you can do the mapping to the core
Neo4j
traverser framework),
results = []
g.v(1).out('friend').out('likes') results // what my friends like
results.sort{a,b - a.name = b.name} // sort resultant vertices by
name
In short, once you have the result of your traversal, you can then
apply
a
comparator to the Collection to sort it as you please --- its just Java
comparators.
See ya,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 8:06 AM, Pere Urbon Bayes wrote:
HI!
I am on the situation of having to traverse neo4j, and then expect the
resultset returned to be ordered in a certain order. I've been
researching a
bit over the traversal API, but I did not find anything related to
that.
I
really will appreciate any tip on that!!
BTW I expect to be possible right?, as we have in relational the
ordering,
or on redis, etc...
/purbon
--
Pere Urbon-Bayes
moviepilot GmbH | Mehringdamm 33 | 10961 Berlin | Germany
Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
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Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
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--
Pere Urbon-Bayes
moviepilot GmbH | Mehringdamm 33 | 10961 Berlin | Germany
Telefon +49 30 616 512 -110 | Fax +49 30 616 512 -133
Re: [Neo4j] Getting sorted results from a traversal
Hey, Isn't that pretty similar to what https://github.com/peterneubauer/graph-collectionshttps://github.com/peterneubauer/graph-collections/tree/master/src/main/java/org/neo4j/collections/sortedtree provides for Neo4j? I dunno. I haven't played with Graph Collections. But I assume so if it implements Java Collections interfaces ? The reason I brought up JDBM2 is because Pere still didn't seem satisfied after Niels recommendation of using graph-collections (that was the first email response to Pere). Just throwing stuff out there -- must...make..Pere...happy... Marko. http://markorodriguez.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] gremlin tables question
Hi,
Do:
t=new Table();v = g.v(2);v.outE.inV.as('node')[0..5].table(t) -1; t;
Read the first trouble shooting for the reason:
https://github.com/tinkerpop/gremlin/wiki/Troubleshooting
v.outE.inV.as('node')[0..5].table(t) returns an iterator.
v.outE.inV.as('node')[0..5].table(t) -1 while(hasNext())s the
iterator.
The Gremlin console will automagically iterate an iterator/iterable. In code
mode, you need to iterate it yourself. -1 does the trick.
Enjoy,
Marko.
http://markorodriguez.com
On Jul 15, 2011, at 8:05 PM, Boris Kizelshteyn wrote:
this works:
- gremlin t=new Table();v = g.v(2);v.outE.inV.as('node')[0..5].table(t);
- == v[95]
- == v[94]
- == v[93]
- == v[92]
- == v[91]
- == v[90]
- gremlin t
- == [node:v[95]]
- == [node:v[94]]
- == [node:v[93]]
- == [node:v[92]]
- == [node:v[91]]
- == [node:v[90]]
While this gives no results:
t=new Table();v = g.v(2);v.outE.inV.as('node')[0..5].table(t); t;
Why?
Many thanks!
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Re: [Neo4j] math question
Hi, That is called a functional relationship. A functional relationship states that there is only one unique y in (xRy) for every x. - e.g. Social Security Number, Father, BornIn Inverse functional relationships are that there is a unique x in (xRy), for every y. See ya, Marko. http://markorodriguez.com On Jul 12, 2011, at 9:39 AM, Niels Hoogeveen wrote: Does anyone know the proper mathematical name for a relationship with the following properties: For all x in X and y in Y it holds that if xRy and xR'y then R = R'. Example: There can be only one IS_PARENT relation from one person to another. Someone cannot be twice parent to the same person. There can be several IS_PRESIDENT_OF relations from one person to an organization. Someone can be president of an organizations from 1992-1997 and again from 2004-2008. Niels ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] math question
Hi, I suppose I would say that (xRy) is both functional and inverse functional. :) Marko. http://markorodriguez.com On Jul 12, 2011, at 12:36 PM, Niels Hoogeveen wrote: Thanks Marko, That's not exactly what I am looking for. I'd like to know what the name is of a relationship where there is only one unique combination of x and y in xRy for every relationship type R. Neo4j allows the creation of 2^64 relationships of the same type between the same two nodes. I'd like to define a type where there can be only one relationship of the same type between the same two nodes (eg. to limit the number of FRIEND relations between two Persons, since it is no use being friends with the same person multiple times, yet I'd like to allow a Person to have multiple WINNER relationships to a certain game (the count of the number of relationships indicating how often a person has been the winner of that game)). Is there any official name for a relationship type where the tuple (x, R, y) must be unique? Niels From: okramma...@gmail.com Date: Tue, 12 Jul 2011 10:27:04 -0600 To: user@lists.neo4j.org Subject: Re: [Neo4j] math question Hi, That is called a functional relationship. A functional relationship states that there is only one unique y in (xRy) for every x. - e.g. Social Security Number, Father, BornIn Inverse functional relationships are that there is a unique x in (xRy), for every y. See ya, Marko. http://markorodriguez.com On Jul 12, 2011, at 9:39 AM, Niels Hoogeveen wrote: Does anyone know the proper mathematical name for a relationship with the following properties: For all x in X and y in Y it holds that if xRy and xR'y then R = R'. Example: There can be only one IS_PARENT relation from one person to another. Someone cannot be twice parent to the same person. There can be several IS_PRESIDENT_OF relations from one person to an organization. Someone can be president of an organizations from 1992-1997 and again from 2004-2008. Niels ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] math question
Hi, Also, R is bijective. http://en.wikipedia.org/wiki/Bijection,_injection_and_surjection Marko. http://markorodriguez.com On Jul 12, 2011, at 12:36 PM, Niels Hoogeveen wrote: Thanks Marko, That's not exactly what I am looking for. I'd like to know what the name is of a relationship where there is only one unique combination of x and y in xRy for every relationship type R. Neo4j allows the creation of 2^64 relationships of the same type between the same two nodes. I'd like to define a type where there can be only one relationship of the same type between the same two nodes (eg. to limit the number of FRIEND relations between two Persons, since it is no use being friends with the same person multiple times, yet I'd like to allow a Person to have multiple WINNER relationships to a certain game (the count of the number of relationships indicating how often a person has been the winner of that game)). Is there any official name for a relationship type where the tuple (x, R, y) must be unique? Niels From: okramma...@gmail.com Date: Tue, 12 Jul 2011 10:27:04 -0600 To: user@lists.neo4j.org Subject: Re: [Neo4j] math question Hi, That is called a functional relationship. A functional relationship states that there is only one unique y in (xRy) for every x. - e.g. Social Security Number, Father, BornIn Inverse functional relationships are that there is a unique x in (xRy), for every y. See ya, Marko. http://markorodriguez.com On Jul 12, 2011, at 9:39 AM, Niels Hoogeveen wrote: Does anyone know the proper mathematical name for a relationship with the following properties: For all x in X and y in Y it holds that if xRy and xR'y then R = R'. Example: There can be only one IS_PARENT relation from one person to another. Someone cannot be twice parent to the same person. There can be several IS_PRESIDENT_OF relations from one person to an organization. Someone can be president of an organizations from 1992-1997 and again from 2004-2008. Niels ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
