Scaling Data-Constrained Language Models

Muennighoff et al., 2023, Scaling Data-Constrained Language Models (Advances in Neural Information Processing Systems 36 (NeurIPS 2023))

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3 Method

  1. How do Muennighoff et al. extend the Chinchilla loss formula to repeated data?
    They replace data \(D\) and parameters \(N\) with effective amounts: \(D' = U_D + U_D R_D^*(1 - e^{-R_D/R_D^*})\), where \(U_D\) is unique tokens and \(R_D\) the number of repetitions (epochs − 1). A symmetric formula discounts parameters beyond what the unique data can use. \(R_D^*\) and its parameter counterpart are fitted.
    161440epochs over the same datarepeated data(effective ÷ unique)fresh data
    Repeated tokens lose value: nearly as good as fresh up to about 4 epochs, then levelling off at about 16× (fitted R*D ≈ 15)
  2. What does the effective-data formula imply about repetition?
    For few repetitions (\(R_D \ll R_D^*\)), repeated tokens are worth almost as much as fresh ones; as repetitions grow, their value decays to zero, so no amount of repetition can beat the loss reachable with \(U_D + U_D R_D^*\) unique tokens.

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