Simon Willison’s Weblog

An animated introduction to Fourier Series (via) Outstanding essay and collection of animated explanations (created using p5.js) by Andrei Ciobanu explaining Fourier transforms, starting with circles, pi, radians and building up from there.

I found Fourier stuff only really clicked for me when it was accompanied by clear animated visuals, and these are a beautiful example of those done really well.

# 3:43 pm / explorables, mathematics, processing

My Twitter thread figuring out the AI features in Microsoft’s Recall. I posed this question on Twitter about why Microsoft Recall (previously) is being described as "AI":

Is it just that the OCR uses a machine learning model, or are there other AI components in the mix here?

I learned that Recall works by taking full desktop screenshots and then applying both OCR and some sort of CLIP-style embeddings model to their content. Both the OCRd text and the vector embeddings are stored in SQLite databases (schema here, thanks Daniel Feldman) which can then be used to search your past computer activity both by text but also by semantic vision terms - "blue dress" to find blue dresses in screenshots, for example. The si_diskann_graph table names hint at Microsoft's DiskANN vector indexing library

A Microsoft engineer confirmed on Hacker News that Recall uses on-disk vector databases to provide local semantic search for both text and images, and that they aren't using Microsoft's Phi-3 or Phi-3 Vision models. As far as I can tell there's no LLM used by the Recall system at all at the moment, just embeddings.

# 10:39 pm / twitter, ai, embeddings, microsoft, sqlite, recall