projection

Definition

Projection maps vectors from one space into another, usually lower-dimensional, most often by multiplying with a learned or fixed matrix. It shows up in two very different places: as the final step of a visualization pipeline, and inside models, where projection layers align embedding widths or produce the queries, keys and values of attention. Since projection discards information by construction, the design question is always which structure it must preserve.

Explainers using this term

• Unsupervised Learning from Scratch — Clustering and Dimensionality ReductionUMAP: Uniform Manifold Approximation and Projection for Dimension Reduction