arXiv Machine Learning

Depth over Fidelity in Fixed-Budget Noisy Evolution Strategies

arXiv:2606. 06555v1 Announce Type: cross Abstract: Noisy evolution strategies under fixed evaluation budgets face a depth-fidelity trade-off: spending evaluations to denoise intra-generation rankings reduces the number of distribution updates the optimizer can execute.

arXiv Machine Learning
Jun 30

BaRA: Bayesian Adaptive Rank Allocation for Parameter-Efficient Fine-Tuning

arXiv:2606. 29184v1 Announce Type: new Abstract: While Low-rank adaptation (LoRA) enables highly efficient fine-tuning by constraining task-specific updates to fixed low-rank subspaces, this rigid design limits representational flexibility and often results in overconfident predictions and miscalibrated uncertainty, especially in low-data regimes.

By Zhibin Duan, Yuhong Wang, Jiahong Fu, Zongsheng Yue, Bo Chen, Zongben Xu
arXiv AI
Sep 10

SwiftExplorer: Training-free Diffusion Model Alignment with Swift Diversity Exploration

SwiftExplorer is a training‑free diffusion model alignment plugin that addresses two key issues in objective‑guided sampling: the loss of diversity due to strong directional bias and the inefficiency of constant guidance. It introduces an Inheritance‑Restart exploration mechanism to prevent early convergence and enhance the likelihood of high‑reward trajectories, while a Quality‑Efficiency arbitration mechanism removes incorrect signals and dynamically stops generation when optimal reward gain is achieved. Experiments show that SwiftExplorer improves preference, fidelity, diversity, and richness across multiple evaluation metrics.

By Renye Yan, Jikang Cheng, You Wu, Bojin Huang, Wei Peng, Zongwei Wang, Ling Liang, Yimao Cai
arXiv Machine Learning
Sep 14

Rank-Efficient LoRA via Joint Tangent-Space Optimization under Isotropic Curvature

The paper introduces ISO-LoRA, an optimizer that improves rank utilization in Low‑Rank Adaptation (LoRA) by coupling factor updates through spectral descent on the induced tangent perturbation in weight space. Experiments on GPT‑2 adaptation show that standard optimizers like AdamW concentrate updates in a few singular directions, whereas ISO-LoRA distributes energy more evenly, leading to higher effective rank and better downstream performance across 0.1B‑7B models. The authors provide theoretical guarantees under a stylized spiked‑gradient model and demonstrate that ISO-LoRA consistently outperforms factor‑wise optimizers, especially at moderate‑to‑large LoRA ranks.

By Zihan Zhu, Zhehang Du, Xuyang Chen, Tim Tsz-Kit Lau, Jiayuan Wu, X. Y. Han, Qi Long, Weijie Su
arXiv Machine Learning
Sep 22

EvoRank: LLM-Guided Evolution of Multi-Objective Learning-to-Rank Pipelines

EvoRank is an open autonomous ranking engineer that uses an LLM-guided evolutionary loop to automatically design complete Learning-to-Rank pipelines—including features, models, losses, and ensembles—for multi-objective e-commerce search. On the Expedia ICDM 2013 dataset, EvoRank converged within 50 iterations on interpretable pipelines that outperform an Optuna-tuned LambdaMART on 60k held-out queries and rank in the top 6 % of the original competition. The authors also introduce a headroom gate that predicts whether the evolutionary loop will be worthwhile before any LLM computation, and they release the system, auditing tools, and a catalog of failure modes to help teams apply the method to their own ranking stacks.

By Rayhan Patel, Shabaz Patel