[PATCH] D59539: [llvm-exegesis] Option to lobotomize dbscan (PR40880)

[Clement Courbet via Phabricator via llvm-commits]

courbet added a comment.

> To reword: because if i do simple clustering by opcode, i will then need to add yet another
>  "stabilization" step - for each cluster, check that every measurement is neighbor of all
>  the other points in that cluster, and if they are not, mark cluster as noise.
>  (well, not every vs. every, just the lower/upper triangle excluding diagonal)

OK I see, thanks. To sum up my understanding: There are some areas where two clusters that should be separate are so noisy that there is a dense region connecting the two clusters, so even taking a small epsilon will not separate them. You want to reject these merged clusters based on the variance of the points within the cluster.

One suggestion I have is to compute the variance within the cluster (this can be done incrementally when adding points to the cluster) and reject clusters where the variance is more than a certain threshold. What do you think ?

> I can do that instead, maybe that would even better than this (no dependency on measurement ordering).

Yes, I would really like to avoid the dependence on the ordering.


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