Pinet: Optimizing hard-constrained neural networks with orthogonal projection layers
Not on the map. Why?
Abstract (arXiv)
We introduce an output layer for neural networks that ensures satisfaction of convex constraints. Our approach, Pinet, leverages operator splitting for rapid and reliable projections in the forward pass, and the implicit function theorem for backpropagation. We deploy Pinet as a feasible-by-design optimization proxy for parametric constrained optimization problems and obtain modest-accuracy solutions faster than traditional solvers when solving a single problem, and significantly faster for a batch of problems. We surpass state-of-the-art learning approaches by orders of magnitude in terms of training time, solution quality, and robustness to hyperparameter tuning, while maintaining similar inference times. Finally, we tackle multi-vehicle motion planning with non-convex trajectory preferences and provide Pinet as a GPU-ready package implemented in JAX.
Key facts. Cited by 19 papers in the map (data through 14 Oct 2026). Builds on 44 of its 75 references that are in the map. First posted on arXiv 14 Aug 2025.
Builds on
44 of 75 references.
References · 44
- 2017Deep reinforcement learning from human preferencescited by 3,912
- 2021Convex optimizationcited by 2,515
- 2016CVXPY: A Python-Embedded Modeling Language for Convex Optimizationcited by 641
- 2018Machine Learning for Combinatorial Optimization: a Methodological Tour d'Horizoncited by 623
- 2019Deep Equilibrium Modelscited by 615
- 2017OptNet: Differentiable Optimization as a Layer in Neural Networkscited by 599
- 2019Differentiable Convex Optimization Layerscited by 465
- 2016Input Convex Neural Networkscited by 414
- 2021Efficient and Modular Implicit Differentiationcited by 203
- 2021DC3: A learning method for optimization with hard constraintscited by 184
- 2017OSQP: An Operator Splitting Solver for Quadratic Programscited by 161
- 2020Monotone operator equilibrium networkscited by 100
32 more
- 2022Tutorial on amortized optimizationcited by 83
- 2019Learning Optimal Solutions for Extremely Fast AC Optimal Power Flowcited by 77
- 2020Lagrangian Duality for Constrained Deep Learningcited by 74
- 2019Physics-informed Autoencoders for Lyapunov-stable Fluid Flow Predictioncited by 67
- 2022Theseus: A Library for Differentiable Nonlinear Optimizationcited by 65
- 2022Self-Supervised Primal-Dual Learning for Constrained Optimizationcited by 61
- 2021Physics-Informed Neural Networks for AC Optimal Power Flowcited by 54
- 2017Imposing Hard Constraints on Deep Networks: Promises and Limitationscited by 43
- 2021Nonsmooth Implicit Differentiation for Machine Learning and Optimizationcited by 43
- 2019Online Mixed-Integer Optimization in Millisecondscited by 38
- 2021Universal Approximation Under Constraints is Possible with Transformerscited by 32
- 2023Learning to Warm-Start Fixed-Point Optimization Algorithmscited by 32
- 2023RAYEN: Imposition of Hard Convex Constraints on Neural Networkscited by 30
- 2022Motion Planning around Obstacles with Convex Optimizationcited by 27
- 2025Energy Matching: Unifying Flow Matching and Energy-Based Models for Generative Modelingcited by 27
- 2022Alternating Differentiation for Optimization Layerscited by 22
- 2024Learning diffusion at lightspeedcited by 22
- 2018Solution Refinement at Regular Points of Conic Problemscited by 21
- 2021Efficient differentiable quadratic programming layers: an ADMM approachcited by 19
- 2025ENFORCE: Nonlinear Constrained Learning with Adaptive-depth Neural Projectioncited by 17
- 2024LinSATNet: The Positive Linear Satisfiability Neural Networkscited by 16
- 2025Optimization Learningcited by 15
- 2022Trust Region Policy Optimization with Optimal Transport Discrepancies: Duality and Algorithm for Continuous Actionscited by 8
- 2022Safe and Efficient Model Predictive Control Using Neural Networks: An Interior Point Approachcited by 7
- 2024GLinSAT: The General Linear Satisfiability Neural Network Layer By Accelerated Gradient Descentcited by 7
- 2023Dynamic Programming in Probability Spaces via Optimal Transportcited by 6
- 2024Metric Learning to Accelerate Convergence of Operator Splitting Methods for Differentiable Parametric Programmingcited by 6
- 2014Faster convergence rates of relaxed Peaceman-Rachford and ADMM under regularity assumptionscited by 4
- 2024Operator Splitting for Convex Constrained Markov Decision Processescited by 4
- 2021Linear convergence of the Douglas-Rachford algorithm via a generic error bound conditioncited by 2
- 2022Distributed and Constrained H2 Control Design via System Level Synthesis and Dual Consensus ADMMcited by 2
- 2021Distributed Feedback Optimisation for Robotic Coordinationcited by 1
Built on by
Citing papers per year: 2025: 5; 2026: 14.
19 papers.
Sort:
By area:
- 2026AutoSOTA: An End-to-End Automated Research System for State-of-the-Art AI Model Discoverycited by 23
- 2025Safe Reinforcement Learning using Action Projection: Safeguard the Policy or the Environment?cited by 5
- 2026LMI-Net: Linear Matrix Inequality--Constrained Neural Networks via Differentiable Projection Layerscited by 4
- 2026Soft-Radial Projection for Constrained End-to-End Learningcited by 3
- 2025SynthPix: A lightspeed PIV image generatorcited by 2
- 2026SnareNet: Flexible Repair Layers for Neural Networks with Hard Constraintscited by 2
- 2026HardNet++: Nonlinear Constraint Enforcement in Neural Networkscited by 2
- 2026Cheap Thrills: Effective Amortized Optimization Using Inexpensive Labelscited by 1
- 2026Parametric Nonconvex Optimization via Convex Surrogatescited by 1
- 2026AdamFLIP: Adaptive Momentum Feedback Linearization Optimization for Hard Constrained PINN Trainingcited by 1
- 2026DiffSlack: Learning under Nonlinear Inequality Constraints via Learnable Slack Variablescited by 1
- 2025Self-Certifying Primal-Dual Optimization Proxies for Large-Scale Batch Economic Dispatchcited by 0
7 more
- 2025Particle Image Velocimetry Refinement via Consensus ADMM for Active Fluid Controlcited by 0
- 2025Flow Gym: A framework for the development, benchmarking, training, and deployment of flow-field quantification methodscited by 0
- 2026NLPOpt-Net: A Learning Method for Nonlinear Optimization with Feasibility Guaranteescited by 0
- 2026Broximal Gradient Descent: A Projection-Free Sister of Projected Gradient Descentcited by 0
- 2026GCPO: Diagnosing and Constraining Subspace Geometry in Rollout RL for LLMscited by 0
- 2026SLP-ProbHard: Probabilistic Hard-Constrained Learning via Structural Latent Parameterizationcited by 0
- 2026Only Project Once: Projection-Adaptive Loss for Exact Constraint Satisfactioncited by 0
- 2026Only Project Once: Projection-Adaptive Loss for Exact Constraint Satisfaction3 Oct 2026
- 2026SLP-ProbHard: Probabilistic Hard-Constrained Learning via Structural Latent Parameterization27 Sep 2026
- 2026GCPO: Diagnosing and Constraining Subspace Geometry in Rollout RL for LLMs12 Aug 2026
- 2026DiffSlack: Learning under Nonlinear Inequality Constraints via Learnable Slack Variables3 Jun 2026
- 2026Broximal Gradient Descent: A Projection-Free Sister of Projected Gradient Descent9 May 2026
- 2026AdamFLIP: Adaptive Momentum Feedback Linearization Optimization for Hard Constrained PINN Training8 May 2026
- 2026NLPOpt-Net: A Learning Method for Nonlinear Optimization with Feasibility Guarantees30 Apr 2026
- 2026HardNet++: Nonlinear Constraint Enforcement in Neural Networks21 Apr 2026
- 2026Parametric Nonconvex Optimization via Convex Surrogates7 Apr 2026
- 2026AutoSOTA: An End-to-End Automated Research System for State-of-the-Art AI Model Discovery7 Apr 2026
- 2026LMI-Net: Linear Matrix Inequality--Constrained Neural Networks via Differentiable Projection Layers7 Apr 2026
- 2026Cheap Thrills: Effective Amortized Optimization Using Inexpensive Labels5 Mar 2026
7 more
- 2026SnareNet: Flexible Repair Layers for Neural Networks with Hard Constraints10 Feb 2026
- 2026Soft-Radial Projection for Constrained End-to-End Learning3 Feb 2026
- 2025Flow Gym: A framework for the development, benchmarking, training, and deployment of flow-field quantification methods12 Dec 2025
- 2025Particle Image Velocimetry Refinement via Consensus ADMM for Active Fluid Control12 Dec 2025
- 2025SynthPix: A lightspeed PIV image generator10 Dec 2025
- 2025Self-Certifying Primal-Dual Optimization Proxies for Large-Scale Batch Economic Dispatch17 Oct 2025
- 2025Safe Reinforcement Learning using Action Projection: Safeguard the Policy or the Environment?16 Sep 2025
- 2026AutoSOTA: An End-to-End Automated Research System for State-of-the-Art AI Model Discoverycited by 23
- 2026LMI-Net: Linear Matrix Inequality--Constrained Neural Networks via Differentiable Projection Layerscited by 4
- 2026Soft-Radial Projection for Constrained End-to-End Learningcited by 3
- 2025SynthPix: A lightspeed PIV image generatorcited by 2
- 2026SnareNet: Flexible Repair Layers for Neural Networks with Hard Constraintscited by 2
- 2026HardNet++: Nonlinear Constraint Enforcement in Neural Networkscited by 2
- 2026Cheap Thrills: Effective Amortized Optimization Using Inexpensive Labelscited by 1
- 2026Parametric Nonconvex Optimization via Convex Surrogatescited by 1
- 2026AdamFLIP: Adaptive Momentum Feedback Linearization Optimization for Hard Constrained PINN Trainingcited by 1
- 2026DiffSlack: Learning under Nonlinear Inequality Constraints via Learnable Slack Variablescited by 1
- 2025Self-Certifying Primal-Dual Optimization Proxies for Large-Scale Batch Economic Dispatchcited by 0
- 2025Particle Image Velocimetry Refinement via Consensus ADMM for Active Fluid Controlcited by 0
12 most cited of 17 All 17 (JSON)
- 2026Only Project Once: Projection-Adaptive Loss for Exact Constraint Satisfaction3 Oct 2026
- 2026SLP-ProbHard: Probabilistic Hard-Constrained Learning via Structural Latent Parameterization27 Sep 2026
- 2026DiffSlack: Learning under Nonlinear Inequality Constraints via Learnable Slack Variables3 Jun 2026
- 2026Broximal Gradient Descent: A Projection-Free Sister of Projected Gradient Descent9 May 2026
- 2026AdamFLIP: Adaptive Momentum Feedback Linearization Optimization for Hard Constrained PINN Training8 May 2026
- 2026NLPOpt-Net: A Learning Method for Nonlinear Optimization with Feasibility Guarantees30 Apr 2026
- 2026HardNet++: Nonlinear Constraint Enforcement in Neural Networks21 Apr 2026
- 2026Parametric Nonconvex Optimization via Convex Surrogates7 Apr 2026
- 2026AutoSOTA: An End-to-End Automated Research System for State-of-the-Art AI Model Discovery7 Apr 2026
- 2026LMI-Net: Linear Matrix Inequality--Constrained Neural Networks via Differentiable Projection Layers7 Apr 2026
- 2026Cheap Thrills: Effective Amortized Optimization Using Inexpensive Labels5 Mar 2026
- 2026SnareNet: Flexible Repair Layers for Neural Networks with Hard Constraints10 Feb 2026
12 newest of 17 All 17 (JSON)