AI engineering glossary · RAG vector search

What is binary quantisation?

Binary quantisation: Reducing every dimension of an embedding to a single bit, usually its sign, so vectors can be compared with very fast Hamming distance. It gives roughly 32-fold memory savings, and is often followed by rescoring with full vectors.

Level: advancedTopic: RAG vector search

Binary quantisation: an example

A 1,024-dimension float vector becomes 128 bytes, and 10 million vectors fit in about 1.3 GB.

Related terms

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Where you learn it

Binary quantisation is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.

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