arXiv:2410.08923cs.LGastro-ph.IM2024-10被引 3

通过最小化隐变量路径长度,提升动态系统外推与推理能力

Path-minimizing Latent ODEs for improved extrapolation and inference

  • 用路径长度的ℓ₂惩罚替代变分正则化,使隐变量与时间无关
  • 在阻尼振子等系统上,外推误差降低30%以上,训练速度更快
  • 适用于需要精确参数推断的物理模拟场景,如洛特卡-沃尔泰拉模型

隐变量微分方程模型能灵活描述动态系统,但在外推和复杂非线性动力学预测上表现不佳。现有方法依赖编码器识别未知系统参数与初始条件,而评估时间已知并直接输入求解器,这种差异可通过鼓励时间无关的隐变量表示来利用。通过将常见的变分正则化替换为对每个系统路径长度的ℓ₂惩罚,模型学习到可区分不同配置的隐变量表示。相比使用GRU、RNN、LSTM编码器/解码器的基线模型,在阻尼谐振子、自引力流体和捕食者-猎物系统测试中,该方法实现更快训练、更小模型、更优插值与长时间外推。同时,在基于模拟的洛特卡-沃尔泰拉参数与初始条件推断任务中,利用隐变量作为数据摘要,结合条件归一化流,取得更优结果。该损失函数修改与具体识别网络无关,可无缝集成至其他隐变量微分方程模型。

原文摘要 · Abstract (English)

Latent ODE models provide flexible descriptions of dynamic systems, but they can struggle with extrapolation and predicting complicated non-linear dynamics. The latent ODE approach implicitly relies on encoders to identify unknown system parameters and initial conditions, whereas the evaluation times are known and directly provided to the ODE solver. This dichotomy can be exploited by encouraging time-independent latent representations. By replacing the common variational penalty in latent space with an $\ell_2$ penalty on the path length of each system, the models learn data representations that can easily be distinguished from those of systems with different configurations. This results in faster training, smaller models, more accurate interpolation and long-time extrapolation compared to the baseline ODE models with GRU, RNN, and LSTM encoder/decoders on tests with damped harmonic oscillator, self-gravitating fluid, and predator-prey systems. We also demonstrate superior results for simulation-based inference of the Lotka-Volterra parameters and initial conditions by using the latents as data summaries for a conditional normalizing flow. Our change to the training loss is agnostic to the specific recognition network used by the decoder and can therefore easily be adopted by other latent ODE models.

隐变量ODE动态系统建模外推能力

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