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Advanced Setups 21 - Jeroen Claus: HDBSCAN
🕑 Added 2022-11-04 16:08:15 +0000 UTCJeroen Claus covers another important clustering algorithm in the thrid part of his series on popular algorithms used in data analysis and visualisation. In this episode he’ll cover an improvement over DBSCAN, called HDBSCAN. Of course Jeroen goes over implementing it in Houdini using VEX.
Comments
Matti Brandmaier
Great tutorial and a very interesting technique. Thank you for this! I hope advanced setups will continue with stuff regarding data analysis. I would like to share some findings I stumbled upon when trying to implement this technique working on larger datasets ( several 100k - millions of points ): using "int npts[] = nearpoints( 0, "@tree!=" + itoa( i@tree ), v@P, 10, 5 );" seems to greatly decrease in performance exponentially with more points to process. I guess this is due to the group call to exclude points with the same tree value. I got the (visually) same result by looking up couple of hundred points within a large radius and comparing the attributes in a foreach loop, this seemed to improve the performance by magnitudes. This is what my wrangle looks like: https://github.com/MattiBRNDMR/houdini_snippets/blob/main/pcfind_exclude_by_same_attribute Another bottleneck I've found when working with large data sets was the foeach point loop to promote the min distance etc. Rebuilding the foreach point loop with vex further accelerated the process: https://github.com/MattiBRNDMR/houdini_snippets/blob/main/get_min_on_a_dataset
Van
Fantastic buildup towards advanced understanding.
