# Exact Optimal Accelerated Complexity for Fixed-Point Iterations

arXiv: https://arxiv.org/abs/2201.11413 · HTML: https://mlsanity.com/paper/2201.11413/

## Key facts

- Cited by 25 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 27 Jan 2022.

## Built on by (most cited first, 25 of 25)

- [PV-Tuning: Beyond Straight-Through Estimation for Extreme LLM Compression](https://mlsanity.com/paper/2405.14852/) (2024)
- [Accelerated Algorithms for Constrained Nonconvex-Nonconcave Min-Max Optimization and Comonotone Inclusion](https://mlsanity.com/paper/2206.05248/) (2022)
- [Towards Weaker Variance Assumptions for Stochastic Optimization](https://mlsanity.com/paper/2504.09951/) (2025)
- [Stochastic Halpern iteration in normed spaces and applications to reinforcement learning](https://mlsanity.com/paper/2403.12338/) (2024)
- [Accelerating Value Iteration with Anchoring](https://mlsanity.com/paper/2305.16569/) (2023)
- [Variance Reduced Halpern Iteration for Finite-Sum Monotone Inclusions](https://mlsanity.com/paper/2310.02987/) (2023)
- [Fundamental Benefit of Alternating Updates in Minimax Optimization](https://mlsanity.com/paper/2402.10475/) (2024)
- [Sublinear Convergence Rates of Extragradient-Type Methods: A Survey on Classical and Recent Developments](https://mlsanity.com/paper/2303.17192/) (2023)
- [Direct Acceleration of Stochastic Root-Finding Without Variance Reduction and Regularization](https://mlsanity.com/paper/2608.12043/) (2026)
- [Variance-Reduced Fast Krasnoselkii-Mann Methods for Finite-Sum Root-Finding Problems](https://mlsanity.com/paper/2406.02413/) (2024)
- [Model-Free Robust Average-Reward Reinforcement Learning with Sample Complexity Analysis](https://mlsanity.com/paper/2505.12462/) (2025)
- [Learning Policy from a Single Trajectory in Average-Reward Markov Decision Process](https://mlsanity.com/paper/2606.16729/) (2026)
- [Faster Fixed-Point Methods for Multichain MDPs](https://mlsanity.com/paper/2506.20910/) (2025)
- [Finite-Time Bounds for Average-Reward Fitted Q-Iteration](https://mlsanity.com/paper/2510.17391/) (2025)
- [A Class of Accelerated Fixed-Point-Based Methods with Delayed Inexact Oracles and Its Applications](https://mlsanity.com/paper/2512.13547/) (2025)
- [RAMPAGE: RAndomized Mid-Point for debiAsed Gradient Extrapolation](https://mlsanity.com/paper/2603.22155/) (2026)
- [Extragradient-Type Methods with O (1/k) Last-Iterate Convergence Rates for Co-Hypomonotone Inclusions](https://mlsanity.com/paper/2302.04099/) (2023)
- [HPPP: Halpern-type Preconditioned Proximal Point Algorithms and Applications to Image Restoration](https://mlsanity.com/paper/2407.13120/) (2024)
- [Control and Reinforcement Learning through the Lens of Optimization: An Algorithmic Perspective](https://mlsanity.com/paper/2512.07377/) (2025)
- [A Unifying View of Anchoring via Operator-Side Tikhonov Regularization](https://mlsanity.com/paper/2605.30905/) (2026)
- [Provable Parameter-Free Fixed-Point Algorithms with Linear Convergence Rates](https://mlsanity.com/paper/2608.09022/) (2026)
- [Oracle Complexity of Stochastic Fixed-Point Equations with Nonexpansive Maps](https://mlsanity.com/paper/2609.09524/) (2026)
- [Stochastic Inertial Krasnosel'skii-Mann Iteration Achieves Near-Optimal Sample Complexity](https://mlsanity.com/paper/2609.28543/) (2026)
- [Dual-Anchor Acceleration Is Near-Optimal for Stochastic Monotone Root-Finding](https://mlsanity.com/paper/2609.36033/) (2026)
- [Optimal Oracle Complexity for Finite-Sum Monotone Inclusions](https://mlsanity.com/paper/2610.05038/) (2026)

## Abstract (arXiv)

Despite the broad use of fixed-point iterations throughout applied mathematics, the optimal convergence rate of general fixed-point problems with nonexpansive nonlinear operators has not been established. This work presents an acceleration mechanism for fixed-point iterations with nonexpansive operators, contractive operators, and nonexpansive operators satisfying a H"older-type growth condition. We then provide matching complexity lower bounds to establish the exact optimality of the acceleration mechanisms in the nonexpansive and contractive setups. Finally, we provide experiments with CT imaging, optimal transport, and decentralized optimization to demonstrate the practical effectiveness of the acceleration mechanism.