NeurIPS 2026 论文列表

Conference on Neural Information Processing Systems

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6,437篇论文

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Trust the Direction, Search the Step: Zero-and-First-Order Methods for LLM Fine-Tuning

Cristian McGee, El Houcine Bergou, Aritra Dutta

展开摘要

Step-size selection remains a central challenge in large-scale neural network optimization: conservative steps slow convergence, while aggressive steps can destabilize training. We propose Zero-and-First-Order optimization (ZFO), a lightweight framework that decouples direction selection from step-size selection. ZFO uses a trusted first-order optimizer to determine the direction and performs zeroth-order evaluations only along this one-dimensional subspace to choose how far to move. Using the current forward-backward pass and two additional fixed-batch function evaluations, ZFO constructs a local model of the objective along the proposed direction and selects a curvature-aware step within a bounded search interval. This yields an adaptive step-selection mechanism with lower cost than full line search. We provide theoretical guarantees showing that shared-sample evaluations produce reliable finite-difference curvature estimates, that the induced local model selects a near-optimal step along the search interval, and that ZFO converges to a neighborhood of a stationary point. Across multiple language models and datasets, ZFO improves accuracy and stability over standard first-order fine-tuning algorithms.

Poster
Trust Region Q Adjoint Matching

Yonghoon Dong, Kyungmin Lee, Changyeon Kim, Jaehyuk Kim, Jinwoo Shin

展开摘要

Off-policy reinforcement learning of pretrained flow policies remains challenging due to the instability of optimization arising from the multi-step sampling process. Recently, Q-learning with Adjoint Matching (QAM) addressed this issue by reformulating into a memoryless stochastic optimal control (SOC) problem with a learned critic. However, QAM inherits a fundamental fragility of critic-guided improvement: small critic errors are amplified when critics are ill-conditioned, often leading to model collapse. This paper introduces Trust Region Q-Adjoint Matching (TRQAM), a stable off-policy fine-tuning algorithm that adaptively controls the path-space KL with pretrained flow policies through projected dual descent. Specifically, we optimize the trust-region parameter $\lambda$ in SOC dynamics, and theoretically show that the path-space KL can be represented by a closed-form function of $\lambda$. As a result, our method can precisely control the exact deviation from pretrained flow policies, achieving stable off-policy RL. Through experiments on 50 OGBench tasks, TRQAM consistently outperforms prior arts in both offline RL and offline-to-online RL. In particular, TRQAM achieves an overall success rate of 68\% in offline RL, substantially improves the strongest baseline at 46\%.

Poster
Trust Region Policy Distillation

Zhengpeng Xie, Li Lyna Zhang, Zeke Xie, Mao Yang

展开摘要

Big goals are hard to achieve all at once; breaking them into small steps is wiser. We present Trust Region Policy Distillation (TOP-D), which transforms the notoriously unstable, high-variance On-Policy Distillation (OPD) into a stable training paradigm by dynamically constructing a proximal teacher. Theoretically, we establish a rigorous framework demonstrating that TOP-D inherently controls gradient variance. By providing a formal global convergence analysis alongside a monotonic improvement bound, we mathematically formalize the reliability and stability of the overall training dynamics. Empirically, TOP-D dramatically enhances training stability, sample efficiency, and final performance on mathematical reasoning tasks. More importantly, TOP-D introduces zero additional computational overhead, positioning itself as a promising alternative to the well-established OPD paradigm.

Poster
Trust Region Continual Learning as an Implicit Meta-Learner

Zekun Wang, Anant Gupta, Chris MacLellan

展开摘要

Continual learning aims to acquire tasks sequentially without catastrophic forgetting, yet standard strategies face a core tradeoff: regularization-based methods (e.g., EWC) can overconstrain updates when task optima are weakly overlapping, while replay-based methods can retain performance but drift due to imperfect replay. We study a hybrid perspective: \emph{trust region continual learning} that combines generative replay with a Fisher-metric trust region constraint. We show that, under local approximations, the resulting update admits a MAML-style interpretation with a single implicit inner step: replay supplies an old-task gradient signal (query-like), while the Fisher-weighted penalty provides an efficient offline curvature shaping (support-like). This yields an emergent meta-learning property in continual learning: the model becomes an initialization that rapidly \emph{re-converges} to prior task optima after each task transition, without explicitly optimizing a bilevel objective. Empirically, on task-incremental diffusion image generation and continual diffusion-policy control, trust region continual learning achieves the best final performance and retention, and consistently recovers early-task performance faster than EWC, replay, and continual meta-learning baselines.

Poster
Trust Guided Decision Transformer

Chainesh Gautam, Raghuram Bharadwaj Diddigi, Chandramouli Kamanchi, Pankaj Dayama, Sumanta Mukherjee, Kameshwaran Sampath

展开摘要

Decision Transformer performance degrades on long rollouts because the conditioning context drifts out of the training distribution. We show that this drift is visible through the model's own next state prediction error, which rises during rollout and stays elevated, giving a direct signal of when context has become unreliable. We introduce Trust Guided Decision Transformer (TGDT), which selects context before applying value guidance. At each step, TGDT evaluates several recent context suffixes using rolling next state prediction error, calibrated against held out offline data via split conformal prediction. It keeps only suffixes whose error stays within the calibrated threshold, then uses a frozen critic to choose the highest value action among the trusted suffixes. This reverses the order used by value only elastic selection, where the critic may choose an action generated from a context the model itself has flagged as unreliable. Experiments on D4RL navigation and locomotion tasks show that state prediction, critic guidance, and hard context reset each solve only part of the problem. TGDT reduces persistent high error runs and improves return over vanilla Decision Transformer, reset based context control, and value only context selection.

Poster
Truncated Riemannian (1+1)-ES for Black-Box Optimization with Intrinsic Dimension Guarantees

Zixu Wu, Hualin Zhang, zhiqiang xu

展开摘要

$(1+1)$-evolution strategy (ES) is a classic variant of evolution strategy for black-box optimization via direct and random search while keeping only a single solution per generation in $\mathbb{R}^n$. Despite convergence with different step-size adaptations, it often remains impractical due to dependence on the unfavorable high dimension of the search space $\mathbb{R}^n$. In fact, many modern optimization problems are naturally constrained to low-dimensional manifolds embedded in very high-dimensional ambient spaces. To see the potential of intrinsic dimensionality reduction for improving practicality, we consider the truncated Riemannian $(1+1)$-ES on a compact Riemannian submanifold $\mathcal{M}\subset\mathbb{R}^n$ and establish its non-asymptotic stationarity guarantee at the standard nonconvex zeroth-order rate of $\widetilde{\mathcal{O}}(\varepsilon^{-4})$ function evaluations. The explicit Gaussian second-moment term in the bound scales with the intrinsic tangent dimension $d=\dim\mathcal{M}$ rather than the ambient dimension $n$, while the remaining truncation dependence is captured by an explicit small-ball drift constant $\alpha_d(R/\sigma_0)$. To the best of our knowledge, this gives the first non-asymptotic stationarity analysis for a comparison-based ES-type method on compact nonconvex Riemannian submanifolds under localized pullback smoothness. Numerical illustrations on sparse PCA over spheres and smooth-surrogate stationarity diagnostics illustrate behavior consistent with the theory and its limitations, while additional experimental studies on truncation radius diagnostics, black-box tuning, and classical evolutionary computation benchmarks support the practical relevance of geometry-aware comparison-based search under limited function-evaluation budgets.

Poster
Trivialized Generative Models on Lie Groups

Neil He, Meenal Jhajharia, Qianxi Wu, Chaoran Cheng, Arindam Banerjee, Ge Liu

展开摘要

Many problems in diverse fields involve data that naturally live on Lie groups. However, existing Riemannian and Lie group generative models still face several limitations. Riemannian flow and consistency models often require position-dependent vector fields, and expensive geometric terms such as Euler-Arnold simulation on general Lie groups or covariant derivatives. Existing Lie group flow models are usually tied to collinear exponential paths, while momentum-based Lie group diffusion relies on compactness assumptions and does not naturally extend to non-compact groups. To address these limitations, we propose Trivialized Generative Models (TGM), a family of generative models that learns endpoint-constrained paths in the fixed Lie algebra and lifts them to the Lie group. This yields Trivialized Flow Matching (TFM), Trivialized Consistency Models (TCM), and momentum-based extensions with endpoint correction, enabling flexible path design, simpler few-step objectives, and generation on non-compact Lie groups. We evaluate TGM on compact SO(3) benchmarks, non-compact $\mathrm{Sp}(4,\mathbb{R})$ datasets motivated by continuous quantum systems and paraxial optics, and real-world protein backbone generation. Across these settings, TGM improves sample quality and efficiency over existing Riemannian and Lie group baselines.

Poster
TrioPose: Native Triple-Stream Diffusion Transformers for Pose-Guided Text-to-Image Generation

dian gu, Zhengyi Yang

展开摘要

Pose-guided text-to-image generation often suffers from limb distortions and feature crosstalk in complex multi-person scenarios. While existing UNet-based adapters struggle with long-range spatial dependencies, emerging Multimodal Diffusion Transformers (MM-DiTs) offer superior global modeling. However, naive signal concatenation in MM-DiTs severely disrupts pre-trained latent distributions. To address this, we propose TrioPose, a native pose-driven framework built upon the SD3.5M architecture. Specifically, we introduce a Triple-Stream Pose-Aware DiT (TSPA-DiT) that treats pose as an independent modality. It employs layer-wise activation and zero-initialized dual-residual injection to smoothly enforce geometric constraints while preserving pre-trained latent stability. To resolve severe multi-instance occlusions, we design a Learnable Relational Bias Mask that categorizes topological connectivity into fine-grained physical states, mapping them into continuous attention soft constraints to effectively decouple inter-instance interference. Furthermore, a Pose-Guided Spatial Loss Weighting strategy modulates the native diffusion objective using heatmap-derived error maps, focusing anatomical supervision strictly on distortion-prone regions. Extensive experiments demonstrate that TrioPose achieves state-of-the-art performance across challenging benchmarks, including Human-Art, CrowdPose, and OCHuman. Notably, it attains an AP of $64.33$ on Human-Art, representing a $30 \\%$ improvement over prior arts, while setting new standards for visual fidelity and text-image semantic alignment in complex multi-human generation.

Poster
Trimming the Long-Tail of Visual World Modeling Evaluation

Bingxuan Li, Yining Hong, Cheng Qian, Hyeonjeong Ha, Jiateng Liu, Zhenhailong Wang, Yue Guo, Yunzhu Li, Heng Ji

展开摘要

Physical interactions follow a long-tailed distribution: a set of common and regular interactions dominates human experience and visual data, while a broad spectrum of rare and irregular interactions remains underrepresented. Although recent world models achieve impressive realism on existing benchmarks, they primarily focus on simulating common physical interactions. This raises a central question: Do world models internalize and generalize the physical principles? In this work, we introduce Tailor-Bench, a benchmark to systemically evaluate this question through the lens of visual world modeling on tool-using interactions. Our benchmarks features three scenario modes (regular, unconventional and impossible), and two settings (predictive and descriptive) under a unified evaluation protocol. Our experimental results reveal a clear long-tail gap in visual world modeling: Performance consistently degrades from Regular to Unconventional and Impossible scenarios, indicating limited generalization beyond common interactions. Failure analysis further shows that models rely on superficial visual patterns, where image models fail to realize correct state changes, and video models additionally suffer from temporal inconsistencies. These limitations persist even with explicit outcome descriptions: Models often revert to familiar patterns in descriptive settings and fail to infer correct outcomes in predictive settings. By exposing systematic failures under long-tail scenarios, Tailor-Bench highlights the need for world models that understand object attributes, causal dynamics, and constraint-aware interactions. We further introduce Tailor-Evaluator-8b, a specialized auto-evaluator trained with structured reasoning supervision, which achieves 0.88 human correlation for scalable evaluation of long-tail visual world modeling.

Poster
Triggering Generalist Reasoning via Predictive Uncertainty for Dual-System VLA

Hyemin Yang, Wooseong Jeong, Giwon Lee, Kuk-Jin Yoon

展开摘要

Dual-system Vision-Language-Action (VLA) models improve real-time robotic control by pairing a slow, reasoning-capable generalist with a fast specialist action expert. However, existing methods invoke the generalist at a fixed frequency, ignoring the fact that decision-making complexity varies throughout a rollout. This static strategy wastes computation in easy phases and can delay intervention when unexpected scene changes require renewed high-level reasoning. We propose TUD (Triggering generalist reasoning via predictive Uncertainty for Dual-system VLA), an adaptive inference framework that selectively skips unnecessary generalist calls. TUD measures the cross-step dispersion of action re-predictions at the upcoming chunk slot, computed from the specialist's existing forwards under the cached generalist context, as a predictive uncertainty signal. This signal captures how much the future action plan shifts as new observations arrive, enabling TUD to invoke the generalist only when the cached plan becomes unreliable, and separates success from failure more reliably than prior uncertainty signals. The signal needs no manually labelled phase boundaries or auxiliary uncertainty model, and is computed from forwards the architecture already runs. On VLA-Arena, TUD finds a more favorable cost--success trade-off than non-adaptive baselines, tracing an entire operating curve as a single threshold is varied, and substantially reduces VLM calls at matched success rate. Our results suggest that predictive uncertainty provides a practical criterion for adaptive reasoning in efficient VLA control.

Poster
Trie-Aware Transformers for Generative Recommendation

Zhenxiang Xu, Sirui Chen, Yong He, Jieyu Yang, Chuan Yuan, Ke Ding, Jing Cao, Can Wang, Jiawei Chen

展开摘要

Generative recommendation (GR) aligns with advances in generative AI by casting next-item prediction as token-level generation rather than score-based ranking. Most GR methods adopt a two-stage pipeline: (i) \textit{item tokenization}, which maps each item to a sequence of discrete, hierarchically organized tokens; and (ii) \textit{autoregressive generation}, which predicts the next item's tokens conditioned on the tokens of user's interaction history. Although hierarchical tokenization induces a prefix tree (trie) over items, standard autoregressive modeling with conventional Transformers often flattens item tokens into a linear stream and overlooks the underlying topology. To address this, we propose TrieRec, a trie-aware generative recommendation method that augments Transformers with structural inductive biases via two positional encodings. First, a \textit{trie-aware absolute positional encoding} aggregates a token's (node's) local structural context (\eg depth, ancestors, and descendants) into the token representation. Second, a \textit{topology-aware relative positional encoding} injects pairwise structural relations into self-attention to capture topology-induced semantic relatedness. TrieRec is also model-agnostic, efficient, and hyperparameter-free. In our experiments, we implement TrieRec within three representative GR backbones, achieving notably improvements of 8.83\% on average across four real-world datasets.

Poster
TrialAgentBench: Evaluating AI Agents for Clinical-Trial Analysis and Long-Horizon Drug-Development Decisions

Bradley M Segal, William J Bolton, Philip Torr, David Clifton, Lei Clifton

展开摘要

Clinical drug development is high stakes. Small statistical errors propagate into trial design, participant exposure, and stop/advance decisions. As agents are increasingly used to support analysis and decision-making, more robust evaluations of their capabilities in clinical domains are needed. We introduce TrialAgentBench, a public benchmark in which agents must analyse participant-level evidence, choose defensible estimands and methods, quantify uncertainty, diagnose assumption failures, and carry those analysis decisions into downstream drug-development decisions. TrialEvalBench contains 400 patient-level analysis tasks across design, assumption, and context tiers. TrialDevBench contains 20 sequential development programmes across five scenario worlds, each starting from a confounded 10,000-patient observational extract and proceeding through asset nomination, endpoint and sample-size design, deterministic phase trials, phase analysis, and stop/advance decisions. The release spans 420 evaluated tasks or programmes, 528,660 simulated subjects, 77.6 million public tabular records, and 1.46 billion row-variable cells. Agents see only participant-facing data; grader-only files contain cell-appropriate targets, deterministic phase state, and scoring code. On TrialEvalBench, GPT-5.4 completes all 400 items but matches the required estimand/method class (e.g., log-HR versus RMST or risk-difference targets) for only 215/400 and produces an acceptable next-trial sample-size plan for 161/400. On TrialDevBench, GPT-5.4 and Claude Opus 4.7 complete all 60 seeded development programme runs per model, yet frequently nominate the wrong initial asset under confounding and choose evidence-supported stop/advance timing in fewer than one-third of programmes. Together, the two suites make clinical-trial decision quality measurable. Current agents can effectively execute familiar analyses, but fail to make the decisions those analyses exist to support.

Poster
TriTD: Tri-Partite Trajectory–Distribution Distillation for Real-Time Autoregressive Video Generation

Jia Li, Xurui Peng, Haowei Zhu, Tianyu Zhao, Jiexi Wang, Youwei Zheng, Yuxi Ren, Xinglong Wu, Xing Wang, Hayden So

展开摘要

Autoregressive (AR) video diffusion has emerged as a leading paradigm for efficient video generation, yet its practical deployment remains bottlenecked by the trade-off between generation quality and inference efficiency. We attribute this bottleneck to three error sources in AR rollouts: the base model error, the train–inference distribution mismatch, and the upstream error propagation. Building on this decomposition, we derive closed-form upper bounds on the per-step and cumulative errors, providing a principled mechanism for jointly optimizing generation quality and inference efficiency. Guided by this analysis, we propose **TriTD**, a **Tri**-Partite **T**rajectory–**D**istribution co-optimized distillation framework with three complementary modules that each target a distinct error term in the bound. First, for ODE initialization, we adopt a Next-Node Trajectory Distillation (NTD) objective and prove a strictly tighter error bound than conventional consistency distillation, reducing the base model error at its source. Second, we introduce Chunk-Graded Noising (CGN), a monotonically non-decreasing per-chunk noising schedule that provably narrows the train–inference noise mismatch and removes redundant KV Cache updates, yielding substantial speedups at no quality cost. Third, we propose Orthogonal-Parallel DMD (OP-DMD), a distribution-matching loss that preserves the original DMD gradient direction while explicitly suppressing unsupervised off-axis drift in the orthogonal subspace, improving both training stability and final generation quality. Extensive experiments show that TriTD consistently surpasses state-of-the-art baselines in visual quality while reaching a real-time throughput of **26.8 FPS** on a single H100 GPU, delivering a balanced quality-efficiency solution for interactive streaming video generation.

Poster
TriBet: Relative E-values for Online Machine-generated Text Detection

Xunye Tian, Zhijian Zhou, Liuhua Peng, Jared Collette, Dino Sejdinovic, Yue Yang, Feng Liu

展开摘要

To ensure a formal guarantee that fully human-written text streams are *not falsely accused* as machine-generated text (MGT), the online betting framework (e-values) has been successfully applied on various existing detectors. However, current two-sample e-value methods fail in two real-world application scenarios: the false positive rate (FPR) is often out of control and the test power drops drastically when (1) the reference domain is similar but not exactly same as test domain (cross-domain), or (2) proxy model of detector is outdated compared to the modern source model. We identify the root cause as an online calibration dilemma: two-sample optimization and betting relies on a null-calibrating offset that is unidentifiable from unlabeled test streams under shift. We resolve this with a triple-sample betting framework (TriBet) that conduct online MGT detection as relative testing against both human and machine references using a witness score, and introduces a conformal test-inclusive domain-shift betting strategy to achieve FPR control without fragile online calibration. We show that TriBet is a level-$\alpha$ sequential test with asymptotic power one, and characterize its expected stopping time. Empirically, we evaluate on 15 source LLMs, 8 proxy models and mixed-document streams, TriBet consistently delivers faster and more powerful detection than both oracle and online betting baselines while keeping FPR strictly controlled.

Poster
TriAxialKV: Toward Extreme Low-Precision KV-Cache Quantization for Agentic Inference Tasks

Hanzhang Shen, Haoran Wu, Yiren Zhao, Robert Mullins

展开摘要

Agentic workloads have emerged as a major workload for LLM inference. They differ significantly from chat-only workloads, requiring long-context processing, the ability to handle multimodal inputs, and structured multi-turn interactions with tool calling capabilities. As a result, their context exhibits structure that can carry different importance along three key axes: temporal recency to the current turn, modality such as text or image tokens, and semantic role such as user queries, tool calls, observations, or reasoning. These axes capture distinct token behaviors and lead to different sensitivities to KV-cache compression. However, existing KV-cache quantization methods are typically homogeneous or exploit only heterogeneity on a single dimension, such as temporal proximity or modality, overlooking the interactions among them. To this end, we introduce TriAxialKV, a novel mixed-precision KV-cache quantization scheme that assigns each token a triaxial tag, calibrates per-tag sensitivity, and allocates INT2/INT4 bitwidths under a fixed memory budget. We implement TriAxialKV as an end-to-end serving system, comprising calibration, mixed-precision quantization and memory management, and custom fused Triton decode kernels. When using Qwen3-VL-32B-Thinking as a computer-use agent operating the OSWorld, TriAxialKV matches the accuracy of SGLang with BF16 KV cache while supporting 4.5$\times$ KV cache size and achieving 30\% higher end-to-end throughput, when running on real GPU systems.

Poster
Tri-Prompting: Controllable Video Generation with Scene, Subject, and Motion Prompts

Zhenghong Zhou, Xiaohang Zhan, Zhiqin Chen, Soo Ye Kim, Nanxuan Zhao, Haitian Zheng, Qing Liu, He Zhang, Zhe Lin, Yuqian Zhou, Jiebo Luo

展开摘要

Recent video diffusion models achieve strong visual quality and temporal coherence, but still lack coordinated control over scene layout, customized subject identity, and camera/subject motion. We study controllable video generation from three prompts: a first-frame scene image, 3D-aware multi-view subject references, and a motion-driving signal. This setting is challenging because background regions are often trackable under camera motion, while foreground subjects can rotate, self-occlude, and reveal new regions that require identity-consistent appearance. We introduce Tri-Prompting, a video diffusion framework that combines multi-view subject conditioning with dual-conditioned motion control. Tri-Prompting uses XYZ tracking points for visible background motion and low-resolution RGB proxies for foreground subject pose, allowing the model to recover fine appearance from multi-view references while retaining flexibility for plausible subject-scene interactions. An inference-time ControlNet scale schedule further balances motion controllability and visual realism. We evaluate Tri-Prompting against specialized baselines: DaS for motion reconstruction and Phantom for subject-driven generation. Tri-Prompting achieves competitive or improved reconstruction quality, stronger multi-view identity preservation, and better 3D consistency, while enabling 3D-aware subject insertion and in-scene manipulation.

Poster
TreemapMix: Dirichlet-Controlled Multi-Image Augmentation for Probability and Ordinal Supervision

Ejafa Bassam, Konstantin Garbers, Yingsheng Geng, Dalton Jens, Jiaxu Qian, Guyue Liu

展开摘要

Data augmentation improves visual recognition by exposing models to synthetic training examples that encourage generalization beyond the observed data. Mixed-sample methods extend this idea by combining multiple images. However, existing approaches either mix only pairs of images or rely on fixed small layouts, limiting control over source count, visible area proportions, and induced supervision. We propose TreemapMix, a distribution-controlled multi-image augmentation that samples source weights from a Dirichlet distribution and assigns them to area-proportional regions using a treemap partition. The resulting known region areas support two complementary objectives. TreemapMix with soft cross-entropy (SCE) treats areas as soft class-probability targets, while TreemapMix with a Plackett-Luce (PL) objective converts areas into ordinal supervision. On ImageNet-1K under a matched training protocol, TreemapMix-SCE achieves substantially lower calibration error than evaluated mixed-sample baselines, while TreemapMix-PL achieves the strongest Top-1 accuracy. Transfer experiments on object detection and instance segmentation suggest that TreemapMix-pretrained features remain useful beyond classification. These results show that controlled multi-image composition can expose the same region-area information as either probability-matching or rank-matching supervision.

Poster
TreeWalker: Partial Evaluation for Grouped Tree-Ensemble Inference

Durmus Karatay, Richard Newman

展开摘要

Many prediction tasks evaluate a tree ensemble on row groups that share feature values: discrete-time survival models expand each patient into $G$ time steps, click-through-rate models score each item in a search session, and scenario analyses vary a few inputs while keeping others fixed. Standard tree-ensemble inference treats each row independently, ignoring this input-side correlation. We instantiate partial evaluation for grouped tree-ensemble inference: constant features are static, varying features dynamic. The algorithm walks each tree once per group, partitions a row bitmask at varying splits, and skips empty subtrees via an unsplit shortcut. We prove a structural work decomposition: per-tree work splits into the constant-projected subtree size $|T_c|$, $G$ leaf writes, and a predicate-mask provisioning cost $Q$. For the trace evaluator, per-row work approaches $(d_v+1)/(d+1)$ as $G \to \infty$, giving asymptotic speedup $1/(1-\bar\rho_G)$. Empirically, TreeWalker delivers ${\sim}3\times$ algorithmic speedup over a row-independent traversal at the reference model size ($T{=}500$, $L{=}8$; $G{=}16$ for SUPPORT/FLCHAIN and empirical groups for Expedia), rising to $6.8$--$7.8\times$ at $G{=}128$ on the survival datasets. For f64 models, outputs match treelite GTIL up to tree-ordering roundoff; for f32 models, TreeWalker's f64 leaf accumulation is close to a Kahan-compensated reference than native f32 on $99.98\%$ of rows, with the remaining $0.02\%$ tied.

Poster
Tree-Structured Synergy of Large Language Models and Bayesian Optimization for Efficient CASH

Beicheng Xu, Weitong Qian, Lingching Tung, Yupeng Lu, Bin Cui

展开摘要

To lower the expertise barrier in machine learning, the AutoML community has focused on the CASH problem, which jointly automates algorithm selection and hyperparameter tuning. While traditional methods like Bayesian Optimization (BO) struggle with cold-start issues, Large Language Models (LLMs) can mitigate these through semantic priors. However, existing LLM-based optimizers generalize poorly to high-dimensional, structured CASH spaces. In this paper, we propose LB-MCTS, a trajectory-structured optimization framework that uses a Monte Carlo Tree Search tree as a shared state for algorithm selection, hyperparameter refinement, and BO–LLM proposer synergy. Within this shared state, BO provides algorithm-specific surrogate modeling for quantitative search, while the LLM exploits path-aware selective memory to generate semantic proposals and reflections. As the surrogate model improves, a reliability-aware proposer policy adaptively shifts from LLM-driven to BO-driven proposals within a unified search trajectory. Experiments on 104 AMLB datasets demonstrate that LB-MCTS consistently outperforms BO-based, LLM-based, and hybrid baselines.

Poster
Tree-Sliced Orlicz Integral Probability Metric

Tuan Hoang, Trung-Khang Tran, Viet-Hoang Tran, Tan Nguyen

展开摘要

Tree-sliced distances have emerged as scalable alternatives to Sliced Wasserstein distances by projecting probability measures onto tree metric spaces and exploiting closed-form transport on trees. Existing tree-sliced constructions, however, are largely built around first-order Wasserstein geometry. While this choice yields efficient computation, it fixes the discrepancy to an $L^1$-type aggregation of subtree mass imbalances and provides limited control over the geometry used in downstream optimization. We propose Tree-Sliced Orlicz IPM (TS-Orlicz), a tree-sliced framework that replaces the tree-level $W_1$ discrepancy with an Orlicz integral probability metric. Building on the tractable formulation of Orlicz IPMs on trees, TS-Orlicz aggregates Orlicz-induced discrepancies over random tree systems while preserving the scalability of tree-sliced computation. By varying the underlying Orlicz function, the framework recovers $L^p$-type behavior and also supports non-polynomial, tail-sensitive geometries that emphasize large subtree discrepancies. We show that TS-Orlicz preserves key properties of tree-sliced constructions and admits efficient computation via closed-form special cases and one-dimensional scalar optimization. We further extend the framework to probability measures on hyperspheres. Experiments across Euclidean and spherical settings, including gradient flows, self-supervised learning, and diffusion-based generative modeling, show that Orlicz-induced tree-sliced discrepancies achieve competitive or improved performance over sliced and tree-sliced baselines while maintaining low computational cost.

Poster