NeurIPS 2026 Papers

3D geometric understanding is undergoing a major transition where rigid, deterministic, optimization-based pipelines are being replaced by large-scale, deep learning models. While recent methods achieve impressive performance on tasks such as multi-view 3D reconstruction and camera pose estimation, they suffer from two critical limitations: $\textbf{(i):}$ current state-of-the-art (SOTA) models require industry-level compute and training corpora, severely limiting accessibility, and $\textbf{(ii):}$ recent approaches remain constrained to modifying existing pretrained transformer models, since substantially changing their architecture would require retraining from scratch. We instead study a complementary direction: training an attention-free state space model for dense 3D understanding. We introduce $\textbf{FlashSSM-3D}$, the first 3D reconstruction state space model capable of performing accurate geometric reasoning over hundreds of images with linear computational complexity. However, training such a model from scratch with competitive performance is impractical under typical academic compute constraints. To address this, we train FlashSSM-3D by distilling knowledge from VGGT, avoiding the need to learn 3D geometric priors entirely from scratch. However, standard distillation losses are poorly suited for dense 3D reconstruction, where preserving real-world spatial structure is essential. We therefore propose a $\textbf{geometry-aware knowledge distillation}$ method specifically tailored for large-scale 3D reconstruction models. Our method introduces two novel losses: a Procrustes-based alignment loss that enforces global structural consistency between student and teacher 3D point predictions, and a camera reprojection loss that directly supervises view-consistent camera geometry between teacher and student. Extensive experiments across multi-view 3D reconstruction and camera pose estimation benchmarks demonstrate that FlashSSM-3D achieves competitive performance while requiring only $\sim25\\%$ of the training data and less than $10\\%$ of the training compute used by VGGT. At inference time, FlashSSM-3D benefits from the practical efficiency of state space models, reconstructing scenes from 500+ views in under 10 seconds while maintaining competitive accuracy.

Diffusion and flow matching have emerged as expressive generative planners for autonomous driving planning, owing to their ability to model high-fidelity and multi-modal trajectory distributions. Nevertheless, existing generative planners are predominantly optimized through imitation learning, which induces a fundamental mismatch between supervised trajectory fitting and closed-loop planning metrics, while their iterative sampling procedures often impose substantial computational overhead. In this paper, we propose FlashPlanner, a goal-conditioned flow-matching planner with online RL finetuning for closed-loop AD planning. FlashPlanner introduces a continuous future goal point as a compact navigation interface for the generative planning policy. This goal is produced by a continuous goal predictor, which is first pretrained and subsequently optimized with RL using closed-loop feedback from multiple candidate goals at each decision step. To support efficient online reinforcement fine-tuning and real-time deployment, FlashPlanner adopts a data-prediction flow-matching objective and removes redundant architectural components in existing diffusion-based planners. Experiments on the closed-loop nuPlan and interPlan benchmarks demonstrate that \textit{FlashPlanner} achieves state-of-the-art planning performance while delivering 6× faster inference (166 FPS) than the previous SOTA baseline (28 FPS). We will open-source our project.

As revealed by the scaling law of Mixture-of-Experts models, model performance ceases improving once the granularity of the intermediate dimension exceeds the optimal threshold, limiting further gains from single-dimension fine-grained design. To address this bottleneck, we propose FineRMoE (FineR-Grained MoE), an architecture that extends fine-grained expert design to both intermediate and output dimensions, aiming to enhance expert specialization beyond the single-dimension limit. We further introduce a bi-level sparse forward computation paradigm and a specialized routing mechanism to govern the activation. In addition, to obviate the prohibitive cost of pre-training from scratch, we devise a generalized upcycling method to build FineRMoE in a cost-effective manner. Extensive experiments performed under the upcycling paradigm demonstrate the superior performance achieved by FineRMoE across ten standard benchmarks. Compared with the strongest upcycling baseline method, FineRMoE achieves significant parameter and inference efficiency gains.

Large language models (LLMs) are increasingly deployed in financial research workflows, where their role is evolving from single-model assistance for human analysts toward autonomous collaboration among multiple agents. Yet recent real-world deployments reveal persistent failures such as factual errors, numerical inconsistencies, and shallow analysis, which can distort assessments of corporate fundamentals and trigger severe economic losses. While existing benchmarks have begun to evaluate such failures, they score all aspects of the generated analysis in one pass, failing to distinguish whether a model fails at foundational stages like auditing and correction, or underperforms at generating research-grade insights. Consequently, it obscures capability bottlenecks and the specialized strengths essential for multi-agent role assignment. To address these gaps, we introduce FinReasoning, a hierarchical benchmark that decomposes the core capabilities of financial research into semantic consistency, data alignment, and deep insight. We further propose a fine-grained evaluation framework that strengthens hallucination-correction assessment and incorporates a 12-indicator rubric for core analytical skills. FinReasoning reveals clear capability stratification across model types. Closed-source models (like Doubao-Seed-1.8) perform strongly overall and are better suited for core reasoning agents in multi-agent financial systems; open-source general models (like Qwen3-235B) show clear capability divergence and consistently underperform on Semantic Consistency, making them less suited for quality-sensitive generation tasks; financial-domain models (like Fin-R1) generate moderate insights but lack foundational auditing skills, requiring upstream quality control for domain-specific analysis. Our work provides a reliable evaluation foundation for multi-agent financial application systems and has already been deployed in pilot tests across several real-world scenarios. The resource is available at https://anonymous.4open.science/r/FinReasoning.

Large language models (LLMs) have achieved remarkable success across diverse tasks, yet their ever-growing model sizes impose significant computational and memory costs that hinder practical deployment. Pruning addresses this by introducing sparsity into weight matrices, but existing layer-wise pruning methods operate independently on each linear layer, ignoring cross-layer dependencies and yielding globally suboptimal masks. End-to-end pruning methods address this limitation but incur prohibitive computational overhead. In this work, we propose FiedlerPrune, a pruning framework that achieves a better balance between the two paradigms by incorporating cross-layer dependencies. Guided by graph theory, FiedlerPrune constructs weighted multipartite graphs over consecutive linear layers within each Transformer block, and derives an inter-layer importance score from each weight's contribution to the Fiedler Value of the corresponding graph. Combined with any intra-layer metric, FiedlerPrune provides a unified and versatile pruning criterion reflecting both local quantitative importance and cross-layer connectivity-preserving importance . Extensive experiments demonstrate that FiedlerPrune consistently improves over layer-wise baselines, and matches or outperforms end-to-end methods at orders-of-magnitude lower pruning cost. We further demonstrate FiedlerPrune's practical utility through inference speedup, compatibility with quantization, and post-pruning fine-tuning.

Feed-forward novel view synthesis has recently shown promising results from sparse posed images, but most existing methods assume that context and target views share a fixed camera family. This homogeneous-camera assumption breaks in practical multi-sensor systems, where perspective, fisheye, and panoramic cameras may coexist and where the target projection may be unseen during training. We study feed-forward NVS across heterogeneous central cameras and identify a key ambiguity introduced by tokenization: a visual token aggregates a projection-dependent bundle of pixel rays, while existing camera encodings mainly expose absolute rays or token-center relations. To address this, we combine token-center relative Camera Positional Encodings and proposed local raymaps, a token-level representation that explicitly describes the intra-patch ray distribution summarized by each token. We further propose projection-aware 2D RoPE, which replaces raw image-grid coordinates with ray-induced angular coordinates so that relative positional reasoning is aligned across camera projections. Together, these components treat diverse cameras as calibrated samplings of a shared ray space rather than separate visual domains. On ScanNet++ with heterogeneous-camera system, our method improves over camera-conditioned baselines under mixed-camera evaluation and demonstrates zero-shot generalization to panoramic views.

Federated Learning (FL) algorithms implicitly assume that clients passively comply with server-side orchestration by sharing local model updates upon server request. However, this overlooks an important aspect in real-world cross-silo environments: clients are often rational agents who may prioritize their utilities such as local model performance over that of the global model. In settings with significant statistical heterogeneity, rational clients may opt out of the federation if the perceived benefits of collaboration fail to meet their local utility thresholds. Such attrition degrades the global model performance and can lead to the collapse of the federated training process. In this work, we introduce FedUCA: Federated Learning by Utility-Constrained Stochastic Aggregation for Improving Rational Participation, a framework that formalizes the server's role as an optimizer seeking to maximize global model performance by sustaining client participation. We substantiate our framework through extensive experiments on standard datasets demonstrating that by prioritizing participation feasibility, FedUCA achieves significantly higher client retention and, consequently, a superior global model performance.

Proxy model-based heterogeneous federated learning enables clients with diverse architectures to collaborate through a shared lightweight intermediary. However, current methods aggregate and distill proxy knowledge in a structure-agnostic manner, ignoring layer-wise convergence dynamics, conflating shared and client-specific information, and transferring knowledge without assessing its reliability. These oversights jointly cause model oscillation, drift, and negative transfer. We propose FedPeel, a framework that makes the aggregation pipeline aware of the internal structure of model parameters. Rather than updating the proxy monolithically, FedPeel selectively aggregates only the layers that have stabilized, decouples their frequency-domain representations to separate generalizable patterns from personalized details, and modulates knowledge transfer intensity on a per-sample basis according to teacher confidence. Theoretical analysis establishes an O(1/T ) convergence rate. Experiments on image, text, and audio benchmarks show that FedPeel consistently outperforms state-of-the-art methods in both accuracy and communication efficiency.

Federated learning (FL) encounters substantial challenges due to heterogeneity, leading to gradient noise, client drift, and partial client participation errors, the last of which is the most pervasive but remains insufficiently addressed in current literature. In this paper, we propose FedAdaVR, a novel FL algorithm aimed at solving heterogeneity issues caused by sporadic client participation by incorporating an adaptive optimiser with a variance reduction technique. This method takes advantage of the most recent stored updates from clients, even when they are absent from the current training round, thereby emulating their presence. Furthermore, we propose FedAdaVR-Quant, which stores client updates in quantised form, significantly reducing the memory requirements (by 50%, 75%, and 87.5%) of FedAdaVR while maintaining highly competitive model performance. We analyse the convergence behaviour of FedAdaVR under general nonconvex conditions and prove that our proposed algorithm can eliminate partial client participation error. Extensive experiments conducted on multiple datasets, under both independent and identically distributed (IID) and non-IID settings, demonstrate that FedAdaVR consistently outperforms state-of-the-art baseline methods.

In this paper, we study federated optimization for solving stochastic variational inequalities (VIs), a problem that has attracted growing attention in recent years. Despite substantial progress, a significant gap remains between existing convergence rates and the state-of-the-art bounds known for federated convex optimization. In this work, we address this limitation by establishing a series of improved convergence rates. First, we show that, for general smooth and monotone variational inequalities, the classical Local Extra SGD algorithm admits tighter guarantees under a refined analysis. Next, we identify an inherent limitation of Local Extra SGD, which can lead to excessive client drift. Motivated by this observation, we propose a new algorithm, the Local Inexact Proximal Point Algorithm with Extra Step (LIPPAX), and show that it mitigates client drift and achieves improved guarantees in several regimes, including bounded Hessian, bounded operator, and low-variance settings. Finally, we extend our results to federated composite variational inequalities and establish improved convergence guarantees.

Diffusion large language models promise parallel token generation, yet inference remains bottlenecked by deciding which masked tokens can be safely committed together. Fast-dLLM addressed this with KV caching and confidence-guided parallel decoding, but its decoding theory uses a homogeneous high-confidence assumption that effectively reduces each candidate set to its weakest selected token. We argue that this leaves speed on the table because real decoding steps exhibit heterogeneous confidence profiles. We propose **Fast-dLLM++**, a training-free extension that introduces *Fr\'{e}chet profile decoding*: selecting parallel commit sets from the full sorted confidence profile rather than a single worst-case confidence. The resulting rule is a heterogeneous-confidence generalization of Fast-dLLM's factor selector and it recovers the previous rule exactly in the equal-confidence case and adds a provable *heterogeneity bonus* when the selected tokens have uneven confidences. Fast-dLLM++ leaves the model, diffusion process, and cache implementation entirely unchanged, making it a drop-in replacement for existing Fast-dLLM decoding. Experiments on GSM8K, MATH, HumanEval, and MBPP with the LLaDA-8B model show that the theoretical improvement translates directly into empirical gains: profile-aware selection improves the accuracy-throughput frontier by exploiting safe parallelism that weakest-token rules miss, achieving up to 37\% higher throughput at comparable accuracy. Our anonymous code release is at https://anonymous.4open.science/r/fast-dllm-plus-plus/.

In multiclass softmax cross-entropy, the full generalized Gauss-Newton (GGN) curvature couples all output logits through the softmax covariance, making second-order updates harder to scale as the number of classes grows. We show that the standard multiclass GGN can be decomposed exactly into a rank-one true-vs-rest term and a positive semidefinite within-competitor covariance term. Fast Gauss-Newton (FGN) retains the first term and drops the second, yielding a positive semidefinite under-approximation of the multiclass GGN that is exact for binary classification. The derivation uses an exact true-vs-rest scalar-margin representation of softmax cross-entropy: the loss and gradient are unchanged, and the approximation enters only at the curvature level. Exploiting the FGN curvature structure, the damped update can be written as an equivalent whitened row-space system with one row per mini-batch example. We solve this system matrix-free by conjugate gradient using Jacobian-vector and vector-Jacobian products of the scalar margin map. Targeted mechanism experiments and a fixed-feature head evaluation support the predictions from the decomposition: FGN stays closest to the full softmax GGN when competitor mass is concentrated or damping is large, and deviates as the dropped within-competitor covariance grows.

The Procrustes-Wasserstein problem asks to match the vectors in two unlabeled point clouds $X$ and $Y$, which are related via a latent orthogonal transformation. This problem appears in unsupervised representation alignment, domain adaptation, and geometric matching, but its computational theory remains limited. We study a planted Gaussian model in which $Y$ is obtained from $X$ via an unknown relabeling, an unknown orthogonal transformation, and additive noise. Departing from the isotropic setting considered in prior work, we assume that the covariance of $X$ is anisotropic, with a power-law spectrum. While closer to real-world data, this structure also enables a directions-first approach: Estimate the dominant eigenspaces of both point clouds, then recover the matching. We prove that a polynomial-time version of this procedure exactly recovers the true relabeling with high probability under explicit scaling conditions. To our knowledge, this is the first computational recovery guarantee for Procrustes-Wasserstein with nontrivial observational noise and dimensions beyond $\log n$, where $n$ is the number of points. Experiments on synthetic data and 3D shapes support the theory, showing that anisotropy favors directions-first methods, can lower runtime and improve recovery.

Diverse applications on signed networks, ranging from leader-follower opinion dynamics to graph semi-supervised learning, fundamentally reduce to solving the discrete Dirichlet boundary value problem. The computational bottleneck of this problem lies in evaluating the entries of the label propagation operator $Q = -L_{U,U}^{-1}L_{U,L}$. While existing approximation methods based on absorbing random walks attempt to address this complexity, they often suffer from high variance and limited precision. To overcome these limitations, we propose MultiTreeQ, a novel and efficient framework designed to approximate the operator's entries with high accuracy. Specifically, MultiTreeQ is constructed based on the Signed Multi-Rooted Spanning Tree and leverages Rao-Blackwellized variance reduction to significantly improve estimation precision. Extensive experiments on real-world networks confirm that MultiTreeQ substantially outperforms existing baselines, scaling to massive graphs with up to 10 million nodes while delivering remarkable improvements in computational efficiency and precision. Our code is available at https://anonymous.4open.science/r/label-propagation-operator-2059/.

We identify a structural weakness in current large language model (LLM) alignment: refusal mechanisms in these models are *fail-open*. While existing approaches tend to encode refusal behaviors across multiple latent features, suppressing a single feature (via prompt-based jailbreaks) is sufficient to collapse alignment, leading to unsafe generation. Motivated by this, we propose *fail-closed alignment* as a design principle for robust LLM safety: refusal mechanisms should remain effective even under partial failures via redundant, independent causal pathways. We present a concrete instantiation of this principle: a progressive alignment framework that iteratively identifies and ablates previously learned refusal directions, forcing the model to reconstruct safety along new, independent subspaces. Across six jailbreak attacks, we achieve the strongest overall robustness (1.7% average attack success rate) while largely preserving generation quality and preventing excessive over-refusals, with negligible computational overhead. Additional analyses confirm that models trained with our method encode multiple, causally independent refusal directions that prompt-based jailbreaks cannot fully suppress, providing empirical support for fail-closed alignment as a principled foundation for robust LLM safety.

Implicit neural representations (INRs) have emerged as powerful tools for encoding signals, yet dominant MLP-based designs often suffer from slow convergence, overfitting to noise, and poor extrapolation. We introduce FUTON (Fourier Tensor Network), which models signals as generalized Fourier series whose coefficients are parameterized by a low-rank tensor decomposition. FUTON implicitly expresses signals as weighted combinations of orthonormal, separable basis functions, combining complementary inductive biases: Fourier bases capture smoothness and periodicity, while the low-rank parameterization enforces low-dimensional spectral structure. We provide theoretical guarantees through a universal approximation theorem and derive an inference algorithm with empirically linear complexity in both the spectral resolution and the input dimension. On image and volume representation, FUTON consistently outperforms state-of-the-art MLP-based INRs while training 2–5× faster.

We present FRUC, a feed-forward 3D Gaussian splatting framework for dynamic scene reconstruction from uncalibrated collaborative driving views. Existing multi-agent reconstruction frameworks are often hindered by rigid prerequisites, demanding precise spatial calibration and slow per-scene optimization. In this paper, we rethink this task by conceptualizing a distributed multi-vehicle network as a spatio-temporally unstructured ego-centric multi-camera system, where the core challenge lies in enhancing ego-centric occluded geometry through collaboration without degrading the ego's accurately observed visible geometry, while preserving reconstruction efficiency. For efficient reconstruction, FRUC is built upon a visual grounded geometric Transformer backbone to enable one-shot, calibration-free inference from a flexible number of multi-vehicle views. To achieve non-destructive geometric supplementation under uncalibrated cross-agent misalignment, FRUC first introduces an ego-centric causal occlusion field that explicitly derives occlusion evolution as latent priors by modeling agent-wise spatio-temporal correlations. Guided by these occlusion priors, it further formulates cross-agent integration as a deterministic residual denoising process via zero-initialized injection, turning challenging cross-agent fusion into bounded residual learning for robust collaborative blind-spot completion. Through extensive evaluations on the real-world V2XReal and UrbanIng-V2X datasets, FRUC is shown to be a new state-of-the-art for the scene reconstruction of dynamic collaborative driving environments, significantly outperforming existing methods in both rendering quality and efficiency.

Asynchronous pipeline parallelism can accelerate distributed model training, but suffers from instability caused by inconsistent gradient computations. We identify a fundamental source of this inconsistency: error signals are coupled to forward-time features, not just parameter states. This means that parameters may evolve as long as they preserve forward-equivalence. Leveraging this insight, we introduce FRESCO, which frames asynchronous updates as a constrained optimization problem: it finds the minimal update modification that acts trivially on the activation subspace. Thus, it serves as a principled generalization beyond the usual synchronous--asynchronous dichotomy: subspace-level protection preserves gradient validity without synchronization stalls, unconstrained-asynchrony instability, or memory overhead that works against pipeline scaling. We demonstrate that FRESCO consistently outperforms representative asynchronous baselines in LLM pre-training, with the gains most pronounced under deep pipelines and high inconsistency levels. Moving beyond the current limitations, FRESCO establishes a new foundation for high-utilization pipeline parallel training, providing a scalable path for large-model development on diverse, resource-constrained systems.

The quadratic computational complexity of attention during prefilling remains a primary bottleneck for the efficiency of long-context LLMS. While sparse attention methods mitigate this cost, existing dynamic approaches rely on computationally expensive $O(N^2)$ scoring, which undermines their practical efficiency gains. In this paper, we observe that long-context attention matrices frequently exhibit prominent diagonal stripe patterns, indicating that query-key pairs separated by specific relative distances yield consistently high correlation. Motivated by this, we propose FFTSparse, a hybrid block-sparse attention framework. By formulating the identification of these dominant attention lags as cross-correlation in the frequency domain via the Fast Fourier Transform (FFT), FFTSparse reduces the cost to identify the sparsity pattern of diagonal stripes to $O(N \log N)$. Additionally, we introduce a lightweight identification module that categorizes the patterns of attention heads and then applies tailored masking strategies accordingly. Extensive evaluations demonstrate that FFTSparse incurs a negligible mask construction overhead of merely 0.02\% relative to full attention. Furthermore, it maintains competitive downstream performance on long-context benchmarks while achieving up to a $7.4x$ prefilling speedup at a 128K sequence length, offering a highly efficient solution for long-context inference of LLMS.