#01Oct 23, 2026
stat.ME
Mixed Engression: Distributional Regression for Multivariate Mixed-Type Responses
Seyong Hwang, Kean Ming Tan, Ji Zhu
Estimating the conditional distribution of multivariate responses with continuous and binary components requires capturing their dependence, respecting their different supports, and accommodating potentially heavy-tailed continuous outcomes. We propose mixed engression, which fits a continuous generator using energy losses induced by bounded discrepancies and then thresholds its soft binary outputs to produce mixed-response samples. Because the discrepancies are bounded, the population objective remains well defined without response-moment assumptions. However, we show that the full-response energy distance for the complete response vector can tend to zero before thresholding yet remain bounded away from zero afterward as response dimensions grow. A separate energy loss on the entire binary vector captures discrepancies obscured by the full-response comparison and controls the effect of thresholding. The generator is therefore fitted using an augmented energy loss that combines the full-response and binary components. Under compositional smoothness of the structural functions and a uniform threshold-margin condition, we derive nonasymptotic bounds on the final sampler's full-response error for sparse ReLU estimators of models driven by Gaussian or Student-t structural noise, yielding polynomial convergence rates up to logarithmic factors. We also establish consistency when the covariate, response, and noise dimensions grow under suitable conditions. Simulations show improved accuracy relative to the comparison methods under the full-response energy distance, including in heavy-tailed settings. Moderate binary augmentation substantially improves binary-distribution accuracy while largely preserving full-response accuracy.
#02Oct 23, 2026
cs.LG
RobustRLlib: A Unified Library and Benchmark for Robust Reinforcement Learning Algorithms
Xi Chen, Fengqi Hu, Zeyu Shen and 5 more
Robust reinforcement learning (RL) is critical for reliable real-world deployment, where policies may fail under diverse shifts and disruptions. Existing robust RL algorithms offer a rich set of mechanisms and principles, yet two major barriers limit their broader potential: limited algorithm reusability and an unclear empirical capability boundary. We introduce RobustRLlib, an algorithm-centric library and benchmark that addresses both challenges. It integrates 17 representative robust online, offline, and safe RL algorithms under a unified interface for substantially improved reusability, together with an enhanced evaluation platform spanning diverse real-world shifts and advanced humanoid and vision-language-action tasks. Systematic evaluation over 273 perturbation configurations provides an up-to-date capability map of current robust RL algorithms, revealing where they remain effective and where substantial robustness gaps persist. As an open-source, user-friendly platform, RobustRLlib offers a reproducible and extensible codebase for applying existing methods to new problems and developing new robust RL algorithms.
#03Oct 23, 2026
cs.CV
Flownomaly: Single-Step Conditional-Mean Recovery for Few-Shot Anomaly Detection
Bernardo Perrone Ribeiro, Erkut Akdag, Egor Bondarev
Few-shot industrial anomaly detection requires modeling category-specific normality from only a handful of defect-free images. Common approaches tie inference to stored exemplars, impose rigid linear structure, or risk reproducing anomalous content. Flownomaly instead casts the problem as normal-counterpart recovery in frozen DINOv2 feature space. Given normal supports, a velocity field is learned through conditional flow matching over frozen patch tokens to transport Gaussian noise toward normal features. Along straight paths, a single recovery step using one evaluation of the optimal field yields the posterior mean of the clean normal token without trajectory integration. The operating time governs how strongly recovery modifies a query token. With no anomalous validation samples available for tuning, a normal-only Jacobian gain-to-noise criterion selects this time from the supports alone. Squared residuals between query tokens and their recovered counterparts yield anomaly signals for both dense localization and image-level detection. Across 1-, 2-, and 4-shot benchmarks on MVTec-AD and VisA, together with sample-shot evaluations on Real-IAD, Flownomaly achieves state-of-the-art performance against recent category-specific methods. In the 1-shot setting, image- and pixel-level AUROC reach 97.8% and 98.0% on MVTec-AD and 95.3% and 98.7% on VisA, with a 2.1-point image-level AUROC improvement over the strongest baseline on VisA. Code is available at https://github.com/b-rbmp/Flownomaly.
#04Oct 23, 2026
cs.LG
Reinforcement Learning with Multi-Step Transition Predictions: A Bellman Theory
Chenbei Lu, Zaiwei Chen, Tongxin Li and 2 more
Multi-step predictions of future transition realizations can improve reinforcement learning, but their value remains difficult to quantify. Directly including these predictions in the state can lead to exponential state-space growth, making direct dynamic programming computationally expensive. We study discounted finite MDPs under a block-feedback protocol: at the start of each K-period block, the decision maker observes $K$-step probabilistic transition predictions for a subset of actions and adapts decisions to observed states within the block. We show that the optimal value satisfies a Bayesian Bellman equation on the original state space. This representation reveals that predictive information creates value by recursively changing the local order of maximization and expectation in the Bellman expansion. We formalize this effect through a Bellman--Jensen analysis and quantify the effects of prediction horizon, error, action coverage, and within-block feedback. We propose block-feedback Bayesian offline learning with online adaptation (BF--BOLA), a model-based algorithm for learning near-optimal policies, and establish upper and lower sample-complexity bounds that match up to logarithmic factors in the stated regimes. The results show that predictions can reduce transition learning to uncovered rows and that learning a near-optimal policy can require fewer prediction samples than estimating the Bayesian value function.
#05Oct 23, 2026
cs.LG
Multiplicative vs. Additive State Coupling in Learned Optimizer Schedules
M. Harper Langston, Pierre-David Letourneau, Dalton Jones and 7 more
We learn schedules for a continuous penalty relaxation of MAX-CUT by backpropagating through an unrolled classical solver. A state-blind schedule generalizes to instances substantially larger than those used for training. A state-adaptive bilinear schedule also generalizes out of distribution, outperforming its untrained baseline across 15 seeds ($t=4.1$). By contrast, an additive ablation with identical inputs and output heads is statistically indistinguishable from the bilinear model in distribution but performs worse than its own baseline out of distribution ($t=-11.7$). This separation appears without regularization and persists across a $30$ round weight-decay sweep: the bilinear advantage remains significant at every tested value, whereas the additive model never recovers. The results in this setting isolate how solver state enters the schedule, rather than state adaptivity alone, as the architectural distinction associated with out-of-distribution transfer.