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Zhi-Qin John Xu

11 accepted papers

2026

Adaptive Preconditioners Trigger Loss Spikes in Adam

ICML 2026poster

Loss spikes commonly emerge during neural network training with the Adam optimizer across diverse architectures and scales, yet their underlying mechanism remains elusive. While previous explanations attribute these phenomena to sharper loss landscapes at lower loss, we show that landscape geometry …

Cited by 0SourceScholar
2026

Towards Understanding Adam Convergence on Highly Degenerate Polynomials

ICML 2026spotlight

Adam is a widely used optimization algorithm in deep learning, yet the specific class of objective functions where it exhibits inherent advantages remains underexplored. Unlike prior studies requiring external schedulers and $\beta_2$ near 1 for convergence, this work investigates the ``natural'' au…

Cited by 0SourceScholar
2026

WebSailor-V2: Bridging the Chasm to Proprietary Agents via Synthetic Data and Scalable Reinforcement Learning

ICLR 2026poster

To significantly advance the capabilities of open-source web agents, we present WebSailor-V2, a complete post-training pipeline encompassing data construction, Supervised Fine-Tuning (SFT), and Reinforcement Learning (RL). Our methodology features two key innovations: (1) On the data front, we devel…

Cited by 0SourceScholar
2025

Achilles' Heel of Mamba: Essential difficulties of the Mamba architecture demonstrated by synthetic data

NeurIPS 2025spotlight

State Space Models (SSMs) have emerged as promising alternatives to attention mechanisms, with the Mamba architecture demonstrating impressive performance and linear complexity for processing long sequences. However, the fundamental differences between Mamba and Transformer architectures remain inco…

Cited by 0SourceScholar
2025

An Analysis for Reasoning Bias of Language Models with Small Initialization

ICML 2025spotlight

Transformer-based Large Language Models (LLMs) have revolutionized Natural Language Processing by demonstrating exceptional performance across diverse tasks. This study investigates the impact of the parameter initialization scale on the training behavior and task preferences of LLMs. We discover th…

Cited by 1SourcePDFScholar
2025

Understanding the Language Model to Solve the Symbolic Multi-Step Reasoning Problem from the Perspective of Buffer Mechanism

EMNLP 2025

Large language models have consistently struggled with complex reasoning tasks, such as mathematical problem-solving. Investigating the internal reasoning mechanisms of these models can help us design better model architectures and training strategies, ultimately enhancing their reasoning capability

Cited by 0SourcePDFScholar
2024

Initialization is Critical to Whether Transformers Fit Composite Functions by Reasoning or Memorizing

NeurIPS 2024poster

Transformers have shown impressive capabilities across various tasks, but their performance on compositional problems remains a topic of debate. In this work, we investigate the mechanisms of how transformers behave on unseen compositional tasks. We discover that the parameter initialization scale…

2024

Stochastic Modified Equations and Dynamics of Dropout Algorithm

ICLR 2024poster

Dropout is a widely utilized regularization technique in the training of neural networks, nevertheless, its underlying mechanism and impact on achieving good generalization abilities remain to be further understood. In this work, we start by undertaking a rigorous theoretical derivation of the stoch…

Cited by 9SourcePDFScholar
2022

Empirical Phase Diagram for Three-layer Neural Networks with Infinite Width

NeurIPS 2022accept

Substantial work indicates that the dynamics of neural networks (NNs) is closely related to their initialization of parameters. Inspired by the phase diagram for two-layer ReLU NNs with infinite width (Luo et al., 2021), we make a step towards drawing a phase diagram for three-layer ReLU NNs with in…

Cited by 29SourcePDFScholar
2022

Towards Understanding the Condensation of Neural Networks at Initial Training

NeurIPS 2022accept

Empirical works show that for ReLU neural networks (NNs) with small initialization, input weights of hidden neurons (the input weight of a hidden neuron consists of the weight from its input layer to the hidden neuron and its bias term) condense onto isolated orientations. The condensation dynamics…

Cited by 32SourcePDFScholar