Anytime Pretraining: Horizon-Free Learning-Rate Schedules with Weight Averaging

Fuente: arXiv
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Auteurs principaux: Meterez, Alexandru, Nair, Pranav Ajit, Morwani, Depen, Pehlevan, Cengiz, Kakade, Sham
Format: Preprint
Publié: 2026
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author Meterez, Alexandru
Nair, Pranav Ajit
Morwani, Depen
Pehlevan, Cengiz
Kakade, Sham
author_facet Meterez, Alexandru
Nair, Pranav Ajit
Morwani, Depen
Pehlevan, Cengiz
Kakade, Sham
contents Large language models are increasingly trained in continual or open-ended settings, where the total training horizon is not known in advance. Despite this, most existing pretraining recipes are not anytime: they rely on horizon-dependent learning rate schedules and extensive tuning under a fixed compute budget. In this work, we provide a theoretical analysis demonstrating the existence of anytime learning schedules for overparameterized linear regression, and we highlight the central role of weight averaging - also known as model merging - in achieving the minimax convergence rates of stochastic gradient descent. We show that these anytime schedules polynomially decay with time, with the decay rate determined by the source and capacity conditions of the problem. Empirically, we evaluate 150M and 300M parameter language models trained at 1-32x Chinchilla scale, comparing constant learning rates with weight averaging and $1/\sqrt{t}$ schedules with weight averaging against a well-tuned cosine schedule. Across the full training range, the anytime schedules achieve comparable final loss to cosine decay. Taken together, our results suggest that weight averaging combined with simple, horizon-free step sizes offers a practical and effective anytime alternative to cosine learning rate schedules for large language model pretraining.
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id arxiv_https___arxiv_org_abs_2602_03702
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Anytime Pretraining: Horizon-Free Learning-Rate Schedules with Weight Averaging
Meterez, Alexandru
Nair, Pranav Ajit
Morwani, Depen
Pehlevan, Cengiz
Kakade, Sham
Machine Learning
Artificial Intelligence
Optimization and Control
Large language models are increasingly trained in continual or open-ended settings, where the total training horizon is not known in advance. Despite this, most existing pretraining recipes are not anytime: they rely on horizon-dependent learning rate schedules and extensive tuning under a fixed compute budget. In this work, we provide a theoretical analysis demonstrating the existence of anytime learning schedules for overparameterized linear regression, and we highlight the central role of weight averaging - also known as model merging - in achieving the minimax convergence rates of stochastic gradient descent. We show that these anytime schedules polynomially decay with time, with the decay rate determined by the source and capacity conditions of the problem. Empirically, we evaluate 150M and 300M parameter language models trained at 1-32x Chinchilla scale, comparing constant learning rates with weight averaging and $1/\sqrt{t}$ schedules with weight averaging against a well-tuned cosine schedule. Across the full training range, the anytime schedules achieve comparable final loss to cosine decay. Taken together, our results suggest that weight averaging combined with simple, horizon-free step sizes offers a practical and effective anytime alternative to cosine learning rate schedules for large language model pretraining.
title Anytime Pretraining: Horizon-Free Learning-Rate Schedules with Weight Averaging
topic Machine Learning
Artificial Intelligence
Optimization and Control
url https://arxiv.org/abs/2602.03702