通过李雅普诺夫指数分析,提升非线性方程求根算法的稳定性与鲁棒性。
Optimizing Parallel Schemes with Lyapunov Exponents and kNN-LLE Estimation
- 基于kNN估计局部最大李雅普诺夫指数,实时监测求解器动态行为。
- 实验证明,该方法可有效识别不稳定参数区域,提升对初值扰动的鲁棒性。
- 适用于需要自稳定性的非线性系统求解,尤其适合高维或含噪声场景。
逆并行求解方案仍是计算非线性系统根的重要工具,但其动力学行为可能极为复杂,从强收缩到振荡或混沌瞬态,取决于算法参数和初值选择。本文提出一种统一的理论-数据驱动方法,用于识别、度量并降低一类单参数逆并行求解器中的不稳定性。理论上,推导了底层迭代映射的稳定性与分岔特性,识别出周期或混沌行为对应的参数区域。计算上,构建基于kNN的局部最大李雅普诺夫指数(LLE)估计微序列管道,应用于从求解器轨迹提取的标量时间序列。滑动窗口李雅普诺夫谱提供细粒度、实时的收缩或不稳定阶段诊断,揭示了粗略线性化分析无法捕捉的瞬态行为。借助此对应关系,提出一种李雅普诺夫引导的参数选择策略,可识别导致稳定行为的求解设置,尤其在估计的LLE显示持续不稳定时。在多组扰动初值的实验中,理论稳定性图与经验李雅普诺夫谱高度一致,并表明所提自适应机制显著提升鲁棒性。研究确立了微序列李雅普诺夫分析作为构建自稳定根求解方案的实用且可解释的工具,并为扩展至高维或含噪声问题开辟了路径。
原文摘要 · Abstract (English)
Inverse parallel schemes remain indispensable tools for computing the roots of nonlinear systems, yet their dynamical behavior can be unexpectedly rich, ranging from strong contraction to oscillatory or chaotic transients depending on the choice of algorithmic parameters and initial states. A unified analytical-data-driven methodology for identifying, measuring, and reducing such instabilities in a family of uni-parametric inverse parallel solvers is presented in this study. On the theoretical side, we derive stability and bifurcation characterizations of the underlying iterative maps, identifying parameter regions associated with periodic or chaotic behavior. On the computational side, we introduce a micro-series pipeline based on kNN-driven estimation of the local largest Lyapunov exponent (LLE), applied to scalar time series derived from solver trajectories. The resulting sliding-window Lyapunov profiles provide fine-grained, real-time diagnostics of contractive or unstable phases and reveal transient behaviors not captured by coarse linearized analysis. Leveraging this correspondence, we introduce a Lyapunov-informed parameter selection strategy that identifies solver settings associated with stable behavior, particularly when the estimated LLE indicates persistent instability. Comprehensive experiments on ensembles of perturbed initial guesses demonstrate close agreement between the theoretical stability diagrams and empirical Lyapunov profiles, and show that the proposed adaptive mechanism significantly improves robustness. The study establishes micro-series Lyapunov analysis as a practical, interpretable tool for constructing self-stabilizing root-finding schemes and opens avenues for extending such diagnostics to higher-dimensional or noise-contaminated problems.
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