StackOverflowError in findSimpleCycles

 * JGraphT version:1.4.0
 * Java version (java -version)/platform:  OpenJDK Runtime Environment Corretto-8.252.09.2 (build 1.8.0_252-b09) for Windows 10 x64

Issue I am trying to list all cycles in a very large sparse graph. I tried JohnsonSimpleCycles.findSimpleCycles() but it quickly generates a java.lang.StackOverflowError. The stacktrace shows a lot of calls “at org.jgrapht.alg.cycle.JohnsonSimpleCycles.getSCCs(JohnsonSimpleCycles.java:207)” that corresponds to the recursive call “getSCCs(startIndex, successorIndex);” I tried:

1. increasing the stack size with -Xss8g,
2. decreasing the dimension of graph using Long for vertexes instead of String for vertexes
3. changing the algorithm to SzwarcfiterLauerSimpleCycles and HawickJamesSimpleCycles, but the result is always the same.

Steps to reproduce (small coding example) I attach the source and the data files to reproduce the issue.

Expected behaviour No StackOverflowError graph.zip

Other information I think the only way to remove the problem is rewriting the getSCCs function in an iterative way instead of the actual recursive way.

[jkinable]

@JZamboni I implemented a non-recursive version of Gabow’s algorithm. In case you need it urgently, my implementation can be found here: https://github.com/jkinable/jgrapht/blob/gabow/jgrapht-core/src/main/java/org/jgrapht/alg/connectivity/GabowStrongConnectivityInspector.java

Sadly, we broke the performance testing framework (see issue #1047 ) during the last release. Until we figure out how to mend the performance testing suite, I can’t compare the non-recursive implementation with the old recursive implementation. I’ll hold off a PR until I know how the new implementation compares against the old one.

[JZamboni]

@jkinable Thanks for the quick reply and implementation! I have tested it with my graph and the issue is gone.