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Research paperComputer Vision · Interpretability · Training & Scaling1 source · Oct 7, 2026

Leaner Transformers Can Easily Learn to Cluster

Recent work shows that transformers can exactly perform Lloyd's algorithm for $k$-means clustering with $n$ points in $d$ dimensions with an embedding size $d{\textsf{emb}} = d+k$ (thus, requiring attention projection matrices of size $(d+k)^2$).

Key points

  • Transformers have in-context learning capabilities, where some known learning algorithms can be executed in the forward pass through the model.
  • In this work, we build upon this result in the following ways: First, we present an equally expressive but smaller transformer that executes Lloyd's algorithm with embedding size $d{\textsf{emb}} = (d + \lceil \log2 k \rceil)$.
  • Next, we train these transformers to learn the clustering algorithms given a distribution of clustering tasks, and theoretically characterize and empirically validate the factors affecting the convergence and in-distribution generalization of learning algorithms based on stochastic gradients.
  • Finally, we probe the general clustering abilities of these learned algorithms (in the form of transformers), and try to understand situations where they succeed and fail.

Sources (1)

  • [1]Leaner Transformers Can Easily Learn to Cluster
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 7, 09:46 AM
    Recent work shows that transformers can exactly perform Lloyd's algorithm for $k$-means clustering with $n$ points in $d$ dimensions with an embedding size $d_{\textsf{emb}} = d+k$ (thus, requiring attention projection matrices of size $(d+k)^2$).
    Transformers have in-context learning capabilities, where some known learning algorithms can be executed in the forward pass through the model.

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