Can't make the pattern matching with a single gremlin statement

Question

I have a graph with dependencies:

dep1 -> dep2 -> ... -> dep3 -> ...
    |                   ^
    +-> dep4            |
    |                   |
    +-------------------+

I'm looking for unnecessary dependencies, which are those where a direct link exists, but also a link through a sub-dependency. In the above example, the link "dep1 -> dep3" is unnecessary.

The cypher statement to find those would be:

start n = node(*)
match n -[:dependency]-> n2,
      n -[:dependency*2..]-> n2
 with n, n2
return distinct id(n), n.name, id(n2), n2.name

I tried to solve this issue with a single gremlin statement (with the "table"-step), but I just couldn't make it work. Is this even possible or do I have to solve this with multiple statements?

Any hints, tips, ideas would be appreciated.

Thanks in advance

score 1 · Accepted Answer · answered Mar 28 '13 at 21:01

1

For what it's worth, this question was discussed/answered in the gremlin-users group here:

https://groups.google.com/forum/?fromgroups=&hl=en#!topic/gremlin-users/N9NYG-aBrvw

answered Mar 28 '13 at 21:01

stephen mallette

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score 0 · Answer 2 · answered Mar 29 '13 at 17:20

Thanks to Marko and Stephen we came up with this solution:

g.V.transform{
    s-> singleStep = [];
        s.as('origin')
            .out('dependency').aggregate(singleStep)
            .out('dependency')
                .loop(1){ true }{ true }
            .retain(singleStep).as('redundant')
            .dedup()
            .table(new Table(), ['origin', 'redundant']){ it.name + '(' + it.id + ')' }
            .cap().next()
}.filter{ it.size() > 0 }

Can't make the pattern matching with a single gremlin statement

2 Answers2