Small Vocabularies, Big Gains: Pretraining and Tokenization in Time Series Models

Fuente: arXiv
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Hauptverfasser: Roger, Alexis, Legate, Gwen, Rasul, Kashif, Nevmyvaka, Yuriy, Rish, Irina
Format: Preprint
Veröffentlicht: 2025
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author Roger, Alexis
Legate, Gwen
Rasul, Kashif
Nevmyvaka, Yuriy
Rish, Irina
author_facet Roger, Alexis
Legate, Gwen
Rasul, Kashif
Nevmyvaka, Yuriy
Rish, Irina
contents Tokenization and transfer learning are two critical components in building state of the art time series foundation models for forecasting. In this work, we systematically study the effect of tokenizer design, specifically scaling and quantization strategies, on model performance, alongside the impact of pretraining versus random initialization. We show that tokenizer configuration primarily governs the representational capacity and stability of the model, while transfer learning influences optimization efficiency and alignment. Using a combination of empirical training experiments and theoretical analyses, we demonstrate that pretrained models consistently leverage well-designed tokenizers more effectively, particularly at smaller vocabulary sizes. Conversely, misaligned tokenization can diminish or even invert the benefits of pretraining. These findings highlight the importance of careful tokenization in time series modeling and suggest that combining small, efficient vocabularies with pretrained weights is especially advantageous in multi-modal forecasting settings, where the overall vocabulary must be shared across modalities. Our results provide concrete guidance for designing tokenizers and leveraging transfer learning in discrete representation learning for continuous signals.
format Preprint
id arxiv_https___arxiv_org_abs_2511_11622
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Small Vocabularies, Big Gains: Pretraining and Tokenization in Time Series Models
Roger, Alexis
Legate, Gwen
Rasul, Kashif
Nevmyvaka, Yuriy
Rish, Irina
Machine Learning
Artificial Intelligence
Computation and Language
Tokenization and transfer learning are two critical components in building state of the art time series foundation models for forecasting. In this work, we systematically study the effect of tokenizer design, specifically scaling and quantization strategies, on model performance, alongside the impact of pretraining versus random initialization. We show that tokenizer configuration primarily governs the representational capacity and stability of the model, while transfer learning influences optimization efficiency and alignment. Using a combination of empirical training experiments and theoretical analyses, we demonstrate that pretrained models consistently leverage well-designed tokenizers more effectively, particularly at smaller vocabulary sizes. Conversely, misaligned tokenization can diminish or even invert the benefits of pretraining. These findings highlight the importance of careful tokenization in time series modeling and suggest that combining small, efficient vocabularies with pretrained weights is especially advantageous in multi-modal forecasting settings, where the overall vocabulary must be shared across modalities. Our results provide concrete guidance for designing tokenizers and leveraging transfer learning in discrete representation learning for continuous signals.
title Small Vocabularies, Big Gains: Pretraining and Tokenization in Time Series Models
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2511.11622