Optimization
Distillation Scaling Laws
Busbridge, Dan, Shidani, Amitis, Weers, Floris, Ramapuram, Jason, Littwin, Etai, Webb, Russ
We provide a distillation scaling law that estimates distilled model performance based on a compute budget and its allocation between the student and teacher. Our findings reduce the risks associated with using distillation at scale; compute allocation for both the teacher and student models can now be done to maximize student performance. We provide compute optimal distillation recipes for when 1) a teacher exists, or 2) a teacher needs training. If many students are to be distilled, or a teacher already exists, distillation outperforms supervised pretraining until a compute level which grows predictably with student size. If one student is to be distilled and a teacher also needs training, supervised learning should be done instead. Additionally, we provide insights across our large scale study of distillation, which increase our understanding of distillation and inform experimental design.
WENDy for Nonlinear-in-Parameter ODEs
Rummel, Nic, Messenger, Daniel A., Becker, Stephen, Dukic, Vanja, Bortz, David M.
The Weak-form Estimation of Non-linear Dynamics (WENDy) algorithm is extended to accommodate systems of ordinary differential equations that are nonlinear-in-parameters (NiP). The extension rests on derived analytic expressions for a likelihood function, its gradient and its Hessian matrix. WENDy makes use of these to approximate a maximum likelihood estimator based on optimization routines suited for non-convex optimization problems. The resulting parameter estimation algorithm has better accuracy, a substantially larger domain of convergence, and is often orders of magnitude faster than the conventional output error least squares method (based on forward solvers). The WENDy.jl algorithm is efficiently implemented in Julia. We demonstrate the algorithm's ability to accommodate the weak form optimization for both additive normal and multiplicative log-normal noise, and present results on a suite of benchmark systems of ordinary differential equations. In order to demonstrate the practical benefits of our approach, we present extensive comparisons between our method and output error methods in terms of accuracy, precision, bias, and coverage.
A First-order Generative Bilevel Optimization Framework for Diffusion Models
Xiao, Quan, Yuan, Hui, Saif, A F M, Liu, Gaowen, Kompella, Ramana, Wang, Mengdi, Chen, Tianyi
Diffusion models, which iteratively denoise data samples to synthesize high-quality outputs, have achieved empirical success across domains. However, optimizing these models for downstream tasks often involves nested bilevel structures, such as tuning hyperparameters for fine-tuning tasks or noise schedules in training dynamics, where traditional bilevel methods fail due to the infinite-dimensional probability space and prohibitive sampling costs. We formalize this challenge as a generative bilevel optimization problem and address two key scenarios: (1) fine-tuning pre-trained models via an inference-only lower-level solver paired with a sample-efficient gradient estimator for the upper level, and (2) training diffusion models from scratch with noise schedule optimization by reparameterizing the lower-level problem and designing a computationally tractable gradient estimator. Our first-order bilevel framework overcomes the incompatibility of conventional bilevel methods with diffusion processes, offering theoretical grounding and computational practicality. Experiments demonstrate that our method outperforms existing fine-tuning and hyperparameter search baselines.
Safety at Scale: A Comprehensive Survey of Large Model Safety
Ma, Xingjun, Gao, Yifeng, Wang, Yixu, Wang, Ruofan, Wang, Xin, Sun, Ye, Ding, Yifan, Xu, Hengyuan, Chen, Yunhao, Zhao, Yunhan, Huang, Hanxun, Li, Yige, Zhang, Jiaming, Zheng, Xiang, Bai, Yang, Wu, Zuxuan, Qiu, Xipeng, Zhang, Jingfeng, Li, Yiming, Sun, Jun, Wang, Cong, Gu, Jindong, Wu, Baoyuan, Chen, Siheng, Zhang, Tianwei, Liu, Yang, Gong, Mingming, Liu, Tongliang, Pan, Shirui, Xie, Cihang, Pang, Tianyu, Dong, Yinpeng, Jia, Ruoxi, Zhang, Yang, Ma, Shiqing, Zhang, Xiangyu, Gong, Neil, Xiao, Chaowei, Erfani, Sarah, Li, Bo, Sugiyama, Masashi, Tao, Dacheng, Bailey, James, Jiang, Yu-Gang
The rapid advancement of large models, driven by their exceptional abilities in learning and generalization through large-scale pre-training, has reshaped the landscape of Artificial Intelligence (AI). These models are now foundational to a wide range of applications, including conversational AI, recommendation systems, autonomous driving, content generation, medical diagnostics, and scientific discovery. However, their widespread deployment also exposes them to significant safety risks, raising concerns about robustness, reliability, and ethical implications. This survey provides a systematic review of current safety research on large models, covering Vision Foundation Models (VFMs), Large Language Models (LLMs), Vision-Language Pre-training (VLP) models, Vision-Language Models (VLMs), Diffusion Models (DMs), and large-model-based Agents. Our contributions are summarized as follows: (1) We present a comprehensive taxonomy of safety threats to these models, including adversarial attacks, data poisoning, backdoor attacks, jailbreak and prompt injection attacks, energy-latency attacks, data and model extraction attacks, and emerging agent-specific threats. (2) We review defense strategies proposed for each type of attacks if available and summarize the commonly used datasets and benchmarks for safety research. (3) Building on this, we identify and discuss the open challenges in large model safety, emphasizing the need for comprehensive safety evaluations, scalable and effective defense mechanisms, and sustainable data practices. More importantly, we highlight the necessity of collective efforts from the research community and international collaboration. Our work can serve as a useful reference for researchers and practitioners, fostering the ongoing development of comprehensive defense systems and platforms to safeguard AI models.
Review for NeurIPS paper: An efficient nonconvex reformulation of stagewise convex optimization problems
Additional Feedback: Update after rebuttal After reading the rebuttal, I am happy with the answers regarding PDHG, and explanations about the proof for backtracking/momentum variants of the method. I find the approach promising. However, I think the work needs improvements in terms of presentation, which, I suggest the authors to consider when revising the paper. Especially the introduction of the idea can be made more friendly for the readers, with more explanations. I suggest the authors to also consider the minor questions in my review that are not mentioned in the rebuttal.
Review for NeurIPS paper: An efficient nonconvex reformulation of stagewise convex optimization problems
The paper considers structured convex optimization where constraints are given in a stage-wise manner. The paper studies a non-convex reformulation for this problem and proposes new algorithms to ensure convergence to global minimizers for both non-degenerate and degenerate cases. The reformulation is proven effective in theory and experiments. The author feedback phase has clarified several aspects, resulting in a consensus on weak acceptance. We hope the detailed feedback with improvement suggestions from the 4 reviews will be implemented for the camera ready version, in particular about the clarity and readability of the paper.
Satisfying Real-world Goals with Dataset Constraints
The goal of minimizing misclassification error on a training set is often just one of several real-world goals that might be defined on different datasets. For example, one may require a classifier to also make positive predictions at some specified rate for some subpopulation (fairness), or to achieve a specified empirical recall. Other real-world goals include reducing churn with respect to a previously deployed model, or stabilizing online training. In this paper we propose handling multiple goals on multiple datasets by training with dataset constraints, using the ramp penalty to accurately quantify costs, and present an efficient algorithm to approximately optimize the resulting non-convex constrained optimization problem. Experiments on both benchmark and real-world industry datasets demonstrate the effectiveness of our approach.
Maximizing Influence in an Ising Network: A Mean-Field Optimal Solution
Influence maximization in social networks has typically been studied in the context of contagion models and irreversible processes. In this paper, we consider an alternate model that treats individual opinions as spins in an Ising system at dynamic equilibrium. We formalize the \textit{Ising influence maximization} problem, which has a natural physical interpretation as maximizing the magnetization given a budget of external magnetic field. Under the mean-field (MF) approximation, we present a gradient ascent algorithm that uses the susceptibility to efficiently calculate local maxima of the magnetization, and we develop a number of sufficient conditions for when the MF magnetization is concave and our algorithm converges to a global optimum. We apply our algorithm on random and real-world networks, demonstrating, remarkably, that the MF optimal external fields (i.e., the external fields which maximize the MF magnetization) exhibit a phase transition from focusing on high-degree individuals at high temperatures to focusing on low-degree individuals at low temperatures.
Reviews: Dimension-Free Iteration Complexity of Finite Sum Optimization Problems
Technical quality: The proofs derived in the paper are sound and well presented. One of the most interesting contributions is the lower bound for stochastic methods (including Stochastic Gradient Descent) which uses Yao's minimax principle, a neat and simple trick. The paper also provides some new insights, e.g. Novelty/originality: Although the lower-bounds derived in this paper are of significant interest, I nevertheless have some concern with the current way the paper is written, especially concerning the differences to [5] that are not clearly stated in the paper. Although the authors seem to imply that they are the first one to derive dimension-free bounds, the work of [5] already derived lower bounds that hold independently of the dimension.
Learning Supervised PageRank with Gradient-Based and Gradient-Free Optimization Methods
In this paper, we consider a non-convex loss-minimization problem of learning Supervised PageRank models, which can account for features of nodes and edges. We propose gradient-based and random gradient-free methods to solve this problem. Our algorithms are based on the concept of an inexact oracle and unlike the state-of-the-art gradient-based method we manage to provide theoretically the convergence rate guarantees for both of them. Finally, we compare the performance of the proposed optimization methods with the state of the art applied to a ranking task.