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Hattie Zhou

6 accepted papers

2025

A Formal Framework for Understanding Length Generalization in Transformers

ICLR 2025poster

A major challenge for transformers is generalizing to sequences longer than those observed during training. While previous works have empirically shown that transformers can either succeed or fail at length generalization depending on the task, theoretical understanding of this phenomenon remains li…

2024

Vanishing Gradients in Reinforcement Finetuning of Language Models

ICLR 2024poster

Pretrained language models are commonly aligned with human preferences and downstream tasks via reinforcement finetuning (RFT), which refers to maximizing a (possibly learned) reward function using policy gradient algorithms. This work identifies a fundamental optimization obstacle in RFT: we prove…

2024

What Algorithms can Transformers Learn? A Study in Length Generalization

ICLR 2024poster

Large language models exhibit surprising emergent generalization properties, yet also struggle on many simple reasoning tasks such as arithmetic and parity. In this work, we focus on length generalization, and we propose a unifying framework to understand when and how Transformers can be expected to…

Cited by 132SourcePDFScholar
2022

Fortuitous Forgetting in Connectionist Networks

ICLR 2022poster

Forgetting is often seen as an unwanted characteristic in both human and machine learning. However, we propose that forgetting can in fact be favorable to learning. We introduce forget-and-relearn as a powerful paradigm for shaping the learning trajectories of artificial neural networks. In this pro…

2019

Deconstructing Lottery Tickets: Zeros, Signs, and the Supermask

NeurIPS 2019poster

The recent "Lottery Ticket Hypothesis" paper by Frankle & Carbin showed that a simple approach to creating sparse networks (keep the large weights) results in models that are trainable from scratch, but only when starting from the same initial weights. The performance of these networks often exceeds…

2019

LCA: Loss Change Allocation for Neural Network Training

NeurIPS 2019poster

Neural networks enjoy widespread use, but many aspects of their training, representation, and operation are poorly understood. In particular, our view into the training process is limited, with a single scalar loss being the most common viewport into this high-dimensional, dynamic process. We propos…