Leland McInnes

@lelandmcinnes.bsky.social

A Mathematician dabbling in Data Science, especially unsupervised learning and data exploration. UMAP, HDBSCAN, PyNNDescent, DataMapPlot. (He/Him)

I am going to be in Boston for the IEEE VIS conference Nov 9 -13 this year! I am keen to talk dimension reduction, clustering, and data maps (UMAP, HDBSCAN, DataMapPlot). If you are going to be at VIS, or are just in Boston, and want to grab a coffee, please reach out. DMs open.

Wikimedia concepts embedded and then mapped to a sphere with UMAP. Trying out topic clusters as continents. Not really sure where it's going.

High-dimensional data is hard to understand. But is it truly cursed? To help you build better intuition for high-dimensional datasets, @lekschas.de and I developed dtour, a visualization tool for smoothly navigating through data projections.

EVoC is a library designed specifically for fast clustering of high dimensional embedding vectors. It can produce high quality clusters extremely efficiently, and requires little to no hyperparameter tuning. Better clustering than UMAP + HDBSCAN; faster clustering than KMeans.

There's a new release of fast-hdbscan out now on PyPI that adds some major new features. - A PLSCAN implementation based on work by Jelmer Bot - Support for diverse metrics via PyNNDescent - A powerful "cannot-link" constraint system for semi-supervised clustering by Richard Hakim

One of the nicest things about Nvidia model releases is that they ship the training data. What does it look like? I sampled 250k examples from 24 datasets in the Nemotron post-training v3 collection and built an interactive Embedding Atlas to explore it.

Interactive Embedding Atlas visualization of 250,000 training examples from NVIDIA's Nemotron post-training v3 collection, colored by category. Distinct clusters are visible for Math (blue, 56k), Code (orange, 45k), Agentic (green, 41k), Instruction Following (red, 25k), Finance (purple, 18k), Multilingual (brown, 18k), Science (pink, 18k), Safety (grey, 16k), and Identity (yellow, 8k). A selected point shows an example from the Agentic function-calling dataset: "I need to know the weight of the creature that can evolve into a Fire Dragon."

This week I'll be delivering a talk and leading a tutorial for the Language AI in Space Sciences Workshop in Baltimore, hosted at STScI. So excited to see folks from all disciplines join the conversation -- including astronomers, engineers, computer scientists, librarians, and linguists.

Conference banner that states the text:

Language AI in Space Sciences Workshop (March 9th - 12th, 2026)

imposed over what looks like a JWST image of a galaxy cluster, and the contours that specify where some astronomy literature categories live in a UMAP-ed embedding space.