Github user newkek commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/921#discussion_r213372950
--- Diff: docs/src/recipes/cycle-detection.asciidoc ---
@@ -48,6 +48,31 @@ the length of the cycle is known to be three and there
is no need to exceed that
cycle. It returned three, because there was one for each vertex that
started the cycle (i.e. one for `A`, one for `B`
and one for `C`). This next line introduce deduplication to only return
unique cycles.
+Note that these traversals won't detect self-loops (vertices directly
connected to themselves).
+To do so, you would need to `.emit()` a Traverser before the repeat()-loop.
+
+[gremlin-groovy]
+----
+g.addV().property(id,'a').as('a').
+ addV().property(id,'b').as('b').
+ addV().property(id,'c').as('c').
+ addV().property(id,'d').as('d').
+ addE('knows').from('a').to('b').
+ addE('knows').from('b').to('c').
+ addE('knows').from('c').to('a').
+ addE('knows').from('a').to('d').
+ addE('knows').from('c').to('d').
+ addE('self').from('a').to('a').iterate()
+g.V().as('a').
+ emit().
+ repeat(outE().inV().simplePath()).
+ times(2).
+ outE().inV().where(eq('a')).
+ path().
+ by(id).
+ by(label)
+----
+
--- End diff --
```
The above case assumed that the need was to only detect cycles over a path
length of three.
It also respected the directionality of the edges by only considering
outgoing ones.
Also note that this traversal won't detect self-loops [....]
--
[self-loop code example]
--
What would need to change to detect cycles of arbitrary length over both
incoming and
outgoing edges, in the modern graph?
--
[bi-directional code example]
--
[...]
```
Is that what you meant?
---
