fix is_cyclic #157
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fix is_cyclic #157
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src/traversals/dfs.jl
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| @@ -10,7 +10,7 @@ Return `true` if graph `g` contains a cycle. | |||
| Uses DFS. | |||
| """ | |||
| function is_cyclic end | |||
| @traitfn is_cyclic(g::::(!IsDirected)) = ne(g) > 0 | |||
| @traitfn is_cyclic(g::::(!IsDirected)) = (ne(g)-(nv(g)-1)) > 0 | |||
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I think this not enough, consider the cyclic graph of 5 vertices
1 -- 2 4 -- 5
\ /
3
then nv(g) == 5 and ne(g) == 4, so that ne(g) - (nv(g) - 1)) == 0. We therefore probably need do check every connceted component separately.
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Thanks for your contribution, I think we should indeed change how this function works for undirected graphs. We probably also need to adapt the tests (that are currently failing) and the documentation for the changed behavior. |
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Yes, this was an improvement only for connected graphs. I'm going to extend it to unconnected ones. |
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Hmm, I'm not sure what happened here? Did you try rebasing the PR? |
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yes |
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new PR here |
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issue #34, now
is_cyclicworks for undirected connected graphs.