MEO throws IllegalStateException: Cannot load the stored orientation because no orientation has been saved

[agitter]

@nisthapanda reported that MEO threw an error that we haven't encountered before when running in Singularity:

{'message': ['Loaded 526346 edges\nLoaded 18547 new vertices (18547 total)\nLoaded 19 sources\nLoaded 20 targets\nFinding paths up to depth 4\nFound 312117 paths using depth 4\nTime (ms): 963605\n\nFixing edges without conflicts and finding conflict edges\n68903 of 526062 edges were used in at least one path\n516367 of 526062 edges did not have conflicts\nTime (ms): 681\n\n', 'INFO:  Using cached SIF image\nException in thread "main" java.lang.IllegalStateException: Cannot load the stored orientation because no orientation has been saved\n\tat alg.EdgeOrientAlg.loadConflictOrientations(EdgeOrientAlg.java:1169)\n\tat alg.EdgeOrientAlg.randPlusSearchSln(EdgeOrientAlg.java:120)\n\tat alg.EOMain.main(EOMain.java:110)\n'], 'return_code': 1}

I believe it originates from this part of the MEO code where it

• randomly initializes a direction (orientation) for all undirected edges that could be used in different directions by different paths
• runs a greedy search flipping edge directions to improve the cumulative weighted directed source-target connections
• saves the greedy search solution if it was better than the previous best solution

The error went away for less demanding MEO parameter combinations, so we suspect it could be related to some type of overflow or memory usage. Based on the printed output, the randomOrient function ran partially, at least through the call to findConflicts, which is where the last output came from. The logging message at the start of localSearchSln is not printed. That may pinpoint the error to these lines.

@nisthapanda could you please briefly report the boundary of parameter combinations that worked and failed?