EFE-based planning is formulated as variational free energy minimization with epistemic priors, decomposing into expected plan costs plus a complexity term.
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Reinforcement Learning and Control as Probabilistic Inference: Tutorial and Review
Canonical reference. 71% of citing Pith papers cite this work as background.
abstract
The framework of reinforcement learning or optimal control provides a mathematical formalization of intelligent decision making that is powerful and broadly applicable. While the general form of the reinforcement learning problem enables effective reasoning about uncertainty, the connection between reinforcement learning and inference in probabilistic models is not immediately obvious. However, such a connection has considerable value when it comes to algorithm design: formalizing a problem as probabilistic inference in principle allows us to bring to bear a wide array of approximate inference tools, extend the model in flexible and powerful ways, and reason about compositionality and partial observability. In this article, we will discuss how a generalization of the reinforcement learning or optimal control problem, which is sometimes termed maximum entropy reinforcement learning, is equivalent to exact probabilistic inference in the case of deterministic dynamics, and variational inference in the case of stochastic dynamics. We will present a detailed derivation of this framework, overview prior work that has drawn on this and related ideas to propose new reinforcement learning and control algorithms, and describe perspectives on future research.
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representative citing papers
Proper EFE-based planning is VFE plus planning and epistemic entropy corrections, realized by channel-reparameterized message passing that captures novelty.
MPPI is re-derived as EM on a probabilistic optimal control problem, producing a generalized EM-MPPI algorithm with convergence analysis for exponential families and explicit Gaussian cases.
ReMax objective induces emergent stochastic exploration in policy gradient RL by optimizing expected max return over retries, implemented via RePPO and shown on MinAtar and Craftax.
RankE co-evolves AR policy and decoder via alternating ranking optimization, improving both FID and CLIP scores on LlamaGen-XL and Janus-Pro where policy-only RL degrades FID.
Volatility promotes exploration and stochasticity suppresses it in Gaussian state-space bandits, shown by extending Gittins indices and deriving the CAUSE exploration bonus via control-as-inference.
Self-distillation token rewards measure input-response-feedback pointwise mutual information, and CREDIT extracts the input-specific component with contrastive baselines to improve LLM reasoning performance.
The paper establishes the first tilde O(epsilon^{-1}) upper bounds and matching lower bounds for forward-KL-regularized offline contextual bandits under single-policy concentrability in both tabular and general function approximation settings.
SoftGAC defines a stochastic bridge from base to action latent that converts the MaxEnt objective into a tractable relative-entropy term reducible to control energy, achieving competitive returns with one-pass sampling.
Reference-sampled weighted SFT with prompt-normalized Boltzmann weights induces the same policy as fixed-reference KL-regularized RLVR, with BOLT as the estimator and a finite one-shot error decomposition separating coverage, variance, and other terms.
Advantage-guided diffusion (SAG and EAG) steers sampling in diffusion world models to higher-advantage trajectories, enabling policy improvement and better sample efficiency on MuJoCo tasks.
Drifting MPC produces a unique distribution over trajectories that trades off data support against optimality and enables efficient receding-horizon planning under unknown dynamics.
A KL-regularized optimal control umbrella recovers classical SOC and RSOC via iterated soft policies and yields linear Bellman operators with path-integral solutions when policy and transition weights coincide.
GenPQR recovers normalized rewards in maximum-entropy IRL by estimating the policy with classification and the soft Q-function with regression, providing modular finite-sample guarantees under general function approximation.
DiffusionNFT performs online RL for diffusion models on the forward process via flow matching and positive-negative contrasts, delivering up to 25x efficiency gains and rapid benchmark improvements over prior reverse-process methods.
HQRE entropy regularization makes multi-agent LLM coordination well-posed, yielding unique equilibria, linear mirror convergence, bounded Bayesian regret, and DICE gains of 4.3–8.5 pp on reasoning/planning tasks.
Finite-sample MPPI inherits the contraction-based stability of a nominal nonlinear MPC policy under an explicit small-gain condition on the approximation error, yielding finite-horizon high-probability localized mean practical stability.
MetaPS trains models via simulation rollouts to select from programmatic strategy libraries for market agents, yielding better performance than fixed or direct LLM baselines across model sizes.
BayesFP provides a unified retraining-free sampler for diffusion and flow policies by casting constrained trajectory generation as posterior sampling via an extended Feynman-Kac corrector.
A distributional reward model p(r|x,y) yields the closed-form effective reward ilde r(x,y) = eta ext{log} ext{E}_p[e^{r/eta}] (pessimistic branch) that unifies prior RLHF aggregation heuristics under Bayesian or KL-DRO views.
Q-VGM offline RL fine-tuning converts critic Q-gradients into residual velocity targets for flow-matching VLAs, raising LIBERO success from 75.0% to 92.5%.
DRIFT achieves multi-turn RL performance via offline importance-weighted SFT by leveraging the equivalence of KL-regularized RL to weighted supervised learning.
FLAG augments state space with flow latent variable to optimize a proxy MaxEnt-RL objective, enabling expressive policies with limited importance samples in high-dimensional control.
A trajectory optimization method performs geometry-aware updates in function space via natural functional gradients and Monte-Carlo estimation on a smoothed surrogate objective to improve feasibility and smoothness in robotic manipulation.
citing papers explorer
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Expected Free Energy-based Planning as Variational Inference
EFE-based planning is formulated as variational free energy minimization with epistemic priors, decomposing into expected plan costs plus a complexity term.
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What Type of Inference is Active Inference?
Proper EFE-based planning is VFE plus planning and epistemic entropy corrections, realized by channel-reparameterized message passing that captures novelty.
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Generalized Model Predictive Path Integral Control as Expectation--Maximization
MPPI is re-derived as EM on a probabilistic optimal control problem, producing a generalized EM-MPPI algorithm with convergence analysis for exponential families and explicit Gaussian cases.
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Emergence of Exploration in Policy Gradient Reinforcement Learning via Retrying
ReMax objective induces emergent stochastic exploration in policy gradient RL by optimizing expected max return over retries, implemented via RePPO and shown on MinAtar and Craftax.
-
RankE: End-to-End Post-Training for Discrete Text-to-Image Generation with Decoder Co-Evolution
RankE co-evolves AR policy and decoder via alternating ranking optimization, improving both FID and CLIP scores on LlamaGen-XL and Janus-Pro where policy-only RL degrades FID.
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Not all uncertainty is alike: volatility, stochasticity, and exploration
Volatility promotes exploration and stochasticity suppresses it in Gaussian state-space bandits, shown by extending Gittins indices and deriving the CAUSE exploration bonus via control-as-inference.
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From Generic Correlation to Input-Specific Credit in On-Policy Self Distillation
Self-distillation token rewards measure input-response-feedback pointwise mutual information, and CREDIT extracts the input-specific component with contrastive baselines to improve LLM reasoning performance.
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Fast Rates for Offline Contextual Bandits with Forward-KL Regularization under Single-Policy Concentrability
The paper establishes the first tilde O(epsilon^{-1}) upper bounds and matching lower bounds for forward-KL-regularized offline contextual bandits under single-policy concentrability in both tabular and general function approximation settings.
-
Generative Actor-Critic with Soft Bridge Policies
SoftGAC defines a stochastic bridge from base to action latent that converts the MaxEnt objective into a tractable relative-entropy term reducible to control energy, achieving competitive returns with one-pass sampling.
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Reference-Sampled Boltzmann Projection for KL-Regularized RLVR: Target-Matched Weighted SFT, Finite One-Shot Gaps, and Policy Mirror Descent
Reference-sampled weighted SFT with prompt-normalized Boltzmann weights induces the same policy as fixed-reference KL-regularized RLVR, with BOLT as the estimator and a finite one-shot error decomposition separating coverage, variance, and other terms.
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Advantage-Guided Diffusion for Model-Based Reinforcement Learning
Advantage-guided diffusion (SAG and EAG) steers sampling in diffusion world models to higher-advantage trajectories, enabling policy improvement and better sample efficiency on MuJoCo tasks.
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Receding-Horizon Control via Drifting Models
Drifting MPC produces a unique distribution over trajectories that trades off data support against optimality and enables efficient receding-horizon planning under unknown dynamics.
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Unifying Entropy Regularization in Optimal Control: From and Back to Classical Objectives via Iterated Soft Policies and Path Integral Solutions
A KL-regularized optimal control umbrella recovers classical SOC and RSOC via iterated soft policies and yields linear Bellman operators with path-integral solutions when policy and transition weights coincide.
-
Inverse Reinforcement Learning with Just Classification and a Few Regressions
GenPQR recovers normalized rewards in maximum-entropy IRL by estimating the policy with classification and the soft Q-function with regression, providing modular finite-sample guarantees under general function approximation.
-
DiffusionNFT: Online Diffusion Reinforcement with Forward Process
DiffusionNFT performs online RL for diffusion models on the forward process via flow matching and positive-negative contrasts, delivering up to 25x efficiency gains and rapid benchmark improvements over prior reverse-process methods.
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DICE: Entropy-Regularized Equilibrium Selection for Stable Multi-Agent LLM Coordination
HQRE entropy regularization makes multi-agent LLM coordination well-posed, yielding unique equilibria, linear mirror convergence, bounded Bayesian regret, and DICE gains of 4.3–8.5 pp on reasoning/planning tasks.
-
Stochastic Stability of Nonlinear MPPI via Contraction Theory and Control Lyapunov Functions
Finite-sample MPPI inherits the contraction-based stability of a nominal nonlinear MPC policy under an explicit small-gain condition on the approximation error, yielding finite-horizon high-probability localized mean practical stability.
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MetaPS: Adaptive Programmatic Strategy Selection for Market Agents
MetaPS trains models via simulation rollouts to select from programmatic strategy libraries for market agents, yielding better performance than fixed or direct LLM baselines across model sizes.
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BayesFP: Posterior Estimation for Flow-Based Policies via Feynman-Kac Sampling
BayesFP provides a unified retraining-free sampler for diffusion and flow policies by casting constrained trajectory generation as posterior sampling via an extended Feynman-Kac corrector.
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A Unifying Lens on Reward Uncertainty in RLHF
A distributional reward model p(r|x,y) yields the closed-form effective reward ilde r(x,y) = eta ext{log} ext{E}_p[e^{r/eta}] (pessimistic branch) that unifies prior RLHF aggregation heuristics under Bayesian or KL-DRO views.
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Q-VGM: Q-Value-Gradient Matching for Off-Policy Reinforcement Learning of Flow-Matching VLA
Q-VGM offline RL fine-tuning converts critic Q-gradients into residual velocity targets for flow-matching VLAs, raising LIBERO success from 75.0% to 92.5%.
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DRIFT: Decoupled Rollouts and Importance-Weighted Fine-Tuning for Efficient Multi-Turn Optimization
DRIFT achieves multi-turn RL performance via offline importance-weighted SFT by leveraging the equivalence of KL-regularized RL to weighted supervised learning.
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FLAG: Flow Policy MaxEnt-RL by Latent Augmented Guidance
FLAG augments state space with flow latent variable to optimize a proxy MaxEnt-RL objective, enabling expressive policies with limited importance samples in high-dimensional control.
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Natural Functional Gradients for Smooth Trajectory Optimization
A trajectory optimization method performs geometry-aware updates in function space via natural functional gradients and Monte-Carlo estimation on a smoothed surrogate objective to improve feasibility and smoothness in robotic manipulation.
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Cross-Domain Energy-Guided Diffusion Generation for Off-Dynamics Reinforcement Learning
CEDGE applies energy-guided trajectory diffusion to generate adapted samples for off-dynamics offline RL, improving planning and policy learning on the ODRL benchmark.
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Implicit Safety Alignment from Crowd Preferences
A hierarchical framework extracts implicit safety criteria from crowd preferences and composes them via high-level policy to reduce safety violations in downstream RL tasks without explicit safety rewards.
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Beyond Mode Collapse: Distribution Matching for Diverse Reasoning
DMPO approximates forward KL minimization in on-policy RL by aligning the policy to a group-level reward-proportional target distribution, yielding 9-12% relative gains over GRPO on NP-Bench and smaller gains on math reasoning.
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Global Convergence of Sampling-Based Nonconvex Optimization through Diffusion-Style Smoothing
Recasts sampling-based nonconvex optimization as smoothed gradient descent to obtain non-asymptotic convergence guarantees and introduces the DIDA annealed algorithm that converges to the global optimum.
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Training-Free Cultural Alignment of Large Language Models via Persona Disagreement
DISCA converts within-country disagreement among World Values Survey personas into a bounded logit correction that reduces cultural misalignment by 10-24% on MultiTP for models 3.8B and larger across 20 countries, without any weight updates.
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Mutual Information Optimal Density Control of Linear Systems and Generalized Schr\"{o}dinger Bridges with Reference Refinement
Alternating optimization for MI-optimal density control of linear systems coincides with that for generalized Schrödinger bridges.
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Drifting Field Policy: A One-Step Generative Policy via Wasserstein Gradient Flow
DFP is a one-step generative policy using Wasserstein gradient flow on a drifting model backbone, with a top-K behavior cloning surrogate, that reaches SOTA on Robomimic and OGBench manipulation tasks.
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Experience Sharing in Mutual Reinforcement Learning for Heterogeneous Language Models
Mutual Reinforcement Learning allows heterogeneous LLMs to exchange experience through mechanisms like Peer Rollout Pooling, Cross-Policy GRPO Advantage Sharing, and Success-Gated Transfer, with outcome-level sharing identified as favorable on the stability-support trade-off.
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PISTO: Proximal Inference for Stochastic Trajectory Optimization
PISTO augments stochastic trajectory optimization with proximal KL regularization, yielding closed-form mean updates via importance sampling that outperform STOMP, CHOMP, CEM, and MPPI on robot arm and MuJoCo benchmarks.
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Listwise Policy Optimization: Group-based RLVR as Target-Projection on the LLM Response Simplex
Listwise Policy Optimization explicitly performs target-projection on the LLM response simplex, unifying and improving group-based RLVR methods with monotonic improvement and flexible divergences.
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Power Distribution Bridges Sampling, Self-Reward RL, and Self-Distillation
The power distribution is the target of power sampling, the closed-form solution to self-reward KL-regularized RL, and the basis for power self-distillation that matches sampling performance at lower cost.
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RL Token: Bootstrapping Online RL with Vision-Language-Action Models
RL Token enables sample-efficient online RL fine-tuning of large VLAs, delivering up to 3x speed gains and higher success rates on real-robot manipulation tasks within minutes to hours.
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Tempered Sequential Monte Carlo for Trajectory and Policy Optimization with Differentiable Dynamics
Tempered sequential Monte Carlo samples from a Boltzmann-tilted distribution over controllers to optimize trajectories and policies under differentiable dynamics.
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DAG-STL: A Hierarchical Framework for Zero-Shot Trajectory Planning under Signal Temporal Logic Specifications
DAG-STL decomposes long-horizon STL planning into decomposition, timed waypoint allocation, and diffusion-based trajectory generation to enable zero-shot planning under unknown dynamics.
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Reinforcement Learning, Optimal Control, and Bayesian Filtering in Data Assimilation
A variational hierarchy unifies Bayesian filtering, variational data assimilation, KL-regularized control, and Kalman methods by proving that posteriors minimize a likelihood-plus-KL objective with evidence as the global infimum.
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Model Predictive Path Integral Control as Preconditioned Gradient Descent
MPPI is recovered as unit-step preconditioned gradient descent on a reduced free-energy objective over parametric sampling distributions, with descent guarantees when the preconditioned Hessian is bounded.
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EvoQRE: Modeling Bounded Rationality in Safety-Critical Traffic Simulation via Evolutionary Quantal Response Equilibrium
EvoQRE models bounded-rationality traffic as general-sum Markov games solved via QRE and entropy-regularized replicator dynamics, with a proven convergence rate and SOTA results on Waymo and nuPlan.
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A KL-regularization Framework for Learning to Plan with Adaptive Priors
PO-MPC unifies prior MPPI-based RL approaches under a single KL-regularized framework that uses the planner distribution as a prior, with new variations yielding performance gains in experiments.
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The Unreasonable Effectiveness of Entropy Minimization in LLM Reasoning
Entropy minimization on self-generated outputs elicits strong reasoning in pretrained LLMs, matching or exceeding supervised RL methods on benchmarks.
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Direct Preference Optimization for Primitive-Enabled Hierarchical RL: A Bilevel Approach
DIPPER uses bi-level optimization and DPO to train the higher-level policy from stationary preference comparisons and value regularization, claiming up to 40% gains on robotic navigation and manipulation tasks while introducing metrics for non-stationarity and infeasible subgoals.
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On Divergence Measures for Training GFlowNets
Introduces statistically efficient estimators for Renyi-α, Tsallis-α, reverse and forward KL divergences with REINFORCE and score-matching control variates for faster GFlowNet training.
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Is Conditional Generative Modeling all you need for Decision-Making?
Return-conditional diffusion models for policies outperform offline RL on benchmarks by circumventing dynamic programming and enable constraint or skill composition.
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Disentangled Skill Embeddings for Reinforcement Learning
Disentangled Skill Embeddings (DSE) is a variational inference framework for multi-task RL using shared parameters and task-specific latent embeddings for generalization to unseen conditions and as skills in hierarchical RL.
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Path-Measure Dynamics of Attention-Driven World Models: A Nonlocal Onsager--Machlup Approach
Derives that attention-induced non-Markovian dynamics yield a nonlocal Onsager-Machlup action whose short-memory expansion recovers the local action of a companion paper.
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FlowAWR: Online Adaptive Flow Reinforcement via Advantage-Weighted Rectification
FlowAWR derives an advantage-weighted rectification for optimal velocity fields in flow models, claiming 2-5x faster convergence than DiffusionNFT on SD3.5-Medium.
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A Path-Space Formulation of Prediction in World Models: From a Single Action to Prediction, Planning, and Irreversibility
Path-space formulation of world-model prediction via Onsager-Machlup action, with attention-based models acquiring asymmetry proportional to data irreversibility.