200k+ submission pairs for 768 submissions (C++)

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Bug Description

Usually for an assignment with 600-700 submissions we only get about 1-2k (total) submission pairs, much less after the actual threshold, but for this analysis it was showing 274,911 submission pairs.

Our similarity threshold was at 80% (0.8) and it was getting stuck during the "Finding clusters" stage for several minutes, I terminated the process before it could ever complete.

We were able to increase the threshold to just 87% (0.87) and although it would display the same number of submission pairs, it was able to complete the analysis and generate the report.

Thought this would be a bug worth reporting, but the solution for now was to just increase the threshold.

JPlag Version

6.2.0

Operating System

No response

Java Version

No response

[tsaglam]

Usually for an assignment with 600-700 submissions we only get about 1-2k (total) submission pairs, much less after the actual threshold, but for this analysis it was showing 274,911 submission pairs.

274,911 comparisons seem normal, as 768 submissions lead to up to (768*(768-1))/2 = 294,528 pairwise comparisons if all submissions are valid/non-empty. However, only some of these comparisons are exported in the report (by default the top 2500). So no issue here.

Our similarity threshold was at 80% (0.8) and it was getting stuck during the "Finding clusters" stage for several minutes, I terminated the process before it could ever complete.

We were able to increase the threshold to just 87% (0.87) and although it would display the same number of submission pairs, it was able to complete the analysis and generate the report.

The clustering error, however, is an issue. We will look into it. Note that clustering is not deterministic, which means re-running the command might also work, depending on the reason for the error. If you want to avoid clustering for now, use --cluster-skip.

Could you provide us with the full CLI command you used?

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@tsaglam

Ah, that makes sense then.

Here's the CLI command:

java -jar jplag-jar-with-dependencies.jar /path/to/files/ -l cpp --similarity-threshold=0.8 -M RUN -r /results/assignment1-result

Here's the Dockerfile that we use for JPlag if you need to confirm which version of Java is being used