通过事件触发机制避免优化陷入无效局部极小,提升固定预算下的性能。
When Descent Is Too Stable: Event-Triggered Hamiltonian Learning to Optimize

- 基于哈密顿系统设计可自适应的优化框架,动态决定何时下降、探索或转移。
- 在固定预算非凸优化任务中,相比固定策略优化器,最佳表现提升显著。
- 适用于需要平衡探索与利用的复杂优化场景,尤其适合梯度信息不完整时。
固定预算的非凸优化失败往往并非因局部下降不稳定,而是过于稳定:到达近似驻点后,优化器可能用剩余评估次数精细化一个无信息的局部最小值。我们将此失败模式建模为优化器动力学的控制问题,要求学习者决定何时下降、何时利用有潜力的盆地,以及何时停滞应触发迁移。提出SHAPE——一种结构化自适应端口-哈密顿任务族优化器,用于基于局部信息的事件触发极小值搜索。从梯度下降动力学出发,将优化提升至增强相空间 $(q, p)$,其中 $q$ 表示候选解,$p$ 携带方向敏感性,控制器 $u$ 处理当前梯度查询信息。每个阶段由学习得到的哈密顿向量场驱动结构化局部下降;跨阶段通过固定事件时钟更新端口与记忆,在分析中将阶段依赖的视野视为直接推广。该设计保持了兼容被动性的结构,且同一训练策略可适配干净、随机或估计的梯度输入。在固定预算非凸优化任务上的实验表明,与固定策略优化器相比,SHAPE提升了最优已知表现。结果表明,自适应哈密顿能量塑造为复杂优化景观中的下降、探索与预算分配提供了原则性机制。
原文摘要 · Abstract (English)
Fixed-budget nonconvex optimization can fail not because local descent is unstable, but because it is too stable: after reaching a nearby stationary point, an optimizer may spend the remaining evaluations refining an uninformative local minimum. We formulate this failure mode as a control problem over optimizer dynamics, where the learner must decide when to descend, when to exploit a promising basin, and when stagnation should trigger movement elsewhere. We introduce SHAPE, a structured adaptive port-Hamiltonian task-family optimizer for event-triggered minima hunting under local information. Starting from gradient-descent dynamics, SHAPE lifts optimization to an augmented phase space $(q, p)$, where the primal state $q$ represents the candidate solution, the cotangent variable $p$ carries directional sensitivity, and a controller $u$ provides processed information from current gradient oracle. Within each stage, a learned Hamiltonian vector field induces structured local descent; across stages, a fixed event clock in the implementation updates ports and memory when local equilibria are detected, with stage-dependent horizons treated in the analysis as a direct generalization. This design preserves a passivity-compatible structure while allowing the same trained policy to use clean, stochastic, or estimated gradient inputs. Experiments on fixed-budget nonconvex optimization tasks show that SHAPE improves best-so-far performance compared with fixed-policy optimizers. These results suggest that adaptive Hamiltonian energy shaping provides a principled mechanism for balancing descent, exploration, and budget allocation in difficult optimization landscapes.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。