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Nikhil Vyas

12 accepted papers

2026

The Potential of Second-Order Optimization for LLMs: A Study with Full Gauss-Newton

ICLR 2026poster

Recent efforts to accelerate LLM pretraining have focused on computationally-efficient approximations that exploit second-order structure. This raises a key question for large-scale training: how much performance is forfeited by these approximations? To probe this question, we establish a practical…

Cited by 0SourcecodeScholar
2025

A New Perspective on Shampoo's Preconditioner

ICLR 2025poster

Shampoo, a second-order optimization algorithm that uses a Kronecker product preconditioner, has recently received increasing attention from the machine learning community. Despite the increasing popularity of Shampoo, the theoretical foundations of its effectiveness are not well understood. The pre…

Cited by 11SourcePDFScholar
2025

Deconstructing What Makes a Good Optimizer for Autoregressive Language Models

ICLR 2025poster

Training language models becomes increasingly expensive with scale, prompting numerous attempts to improve optimization efficiency. Despite these efforts, the Adam optimizer remains the most widely used, due to a prevailing view that it is the most effective approach. We aim to compare several optim…

Cited by 0SourcePDFScholar
2025

How Does Critical Batch Size Scale in Pre-training?

ICLR 2025poster

Training large-scale models under given resources requires careful design of parallelism strategies. In particular, the efficiency notion of critical batch size (CBS), concerning the compromise between time and compute, marks the threshold beyond which greater data parallelism leads to diminishing r…

2025

Mixture of Parrots: Experts improve memorization more than reasoning

ICLR 2025poster

The Mixture-of-Experts (MoE) architecture enables a significant increase in the total number of model parameters with minimal computational overhead. However, it is not clear what performance tradeoffs, if any, exist between MoEs and standard dense transformers. In this paper, we show that as we i…

Cited by 3SourcePDFScholar
2025

SOAP: Improving and Stabilizing Shampoo using Adam for Language Modeling

ICLR 2025poster

There is growing evidence of the effectiveness of Shampoo, a higher-order preconditioning method, over Adam in deep learning optimization tasks. However, Shampoo's drawbacks include additional hyperparameters and computational overhead when compared to Adam, which only updates running averages of fi…

2024

Beyond Implicit Bias: The Insignificance of SGD Noise in Online Learning

ICML 2024spotlight

The success of SGD in deep learning has been ascribed by prior works to the *implicit bias* induced by finite batch sizes (''SGD noise''). While prior works focused on *offline learning* (i.e., multiple-epoch training), we study the impact of SGD noise on *online* (i.e., single epoch) learning. Thro…

Cited by 3SourcePDFScholar
2024

Distinguishing the Knowable from the Unknowable with Language Models

ICML 2024poster

We study the feasibility of identifying *epistemic* uncertainty (reflecting a lack of knowledge), as opposed to *aleatoric* uncertainty (reflecting entropy in the underlying distribution), in the outputs of large language models (LLMs) over free-form text. In the absence of ground-truth probabilitie…

2023

Feature-Learning Networks Are Consistent Across Widths At Realistic Scales

NeurIPS 2023poster

We study the effect of width on the dynamics of feature-learning neural networks across a variety of architectures and datasets. Early in training, wide neural networks trained on online data have not only identical loss curves but also agree in their point-wise test predictions throughout training.…

Cited by 31SourcePDFScholar
2023

On the Benefits of Learning to Route in Mixture-of-Experts Models

EMNLP 2023long main

Mixture-of-Expert (MoE) Transformer models, such as the Switch Transformer, allow us to successfully scale up model sizes while keeping the amount of compute time fixed. Prior work has established the computational efficiency benefits of using these models. A core component of these models is a rout…

Cited by 0SourceScholar
2018

Thwarting Adversarial Examples: An $L_0$-Robust Sparse Fourier Transform

NeurIPS 2018poster

We give a new algorithm for approximating the Discrete Fourier transform of an approximately sparse signal that is robust to worst-case $L_0$ corruptions, namely that some coordinates of the signal can be corrupt arbitrarily. Our techniques generalize to a wide range of linear transformations that a…

Cited by 68SourcePDFScholar