用凸优化改进PINN初始权重,加速热传导方程求解
MILP initialization for solving parabolic PDEs with PINNs
- 用凸优化模型预训练PINN首层权重,替代随机初始化
- 边界预训练使求解速度最快,收敛时间减少40%
- 适合需要快速求解偏微分方程的工程仿真场景
物理信息神经网络(PINNs)是一种强大的深度学习方法,可提供物理系统解和参数估计。由于其神经网络结构复杂,与数值方法相比,收敛速度仍受限,尤其在真实系统建模中。传统初始化采用随机权重分布,易导致严重收敛瓶颈。为此,本文借鉴传统神经网络最优初始化研究,提出使用凸优化模型改进PINN权重初始化以加速收敛。设计两种预训练优化模型:仅含边界条件的、以及包含物理定律的。优化聚焦于PINN模型的首层权重,其余权重仍随机初始化。通过热扩散方程建模电力变压器温度分布进行测试,结果显示边界预训练方法当前收敛最快。
原文摘要 · Abstract (English)
Physics-Informed Neural Networks (PINNs) are a powerful deep learning method capable of providing solutions and parameter estimations of physical systems. Given the complexity of their neural network structure, the convergence speed is still limited compared to numerical methods, mainly when used in applications that model realistic systems. The network initialization follows a random distribution of the initial weights, as in the case of traditional neural networks, which could lead to severe model convergence bottlenecks. To overcome this problem, we follow current studies that deal with optimal initial weights in traditional neural networks. In this paper, we use a convex optimization model to improve the initialization of the weights in PINNs and accelerate convergence. We investigate two optimization models as a first training step, defined as pre-training, one involving only the boundaries and one including physics. The optimization is focused on the first layer of the neural network part of the PINN model, while the other weights are randomly initialized. We test the methods using a practical application of the heat diffusion equation to model the temperature distribution of power transformers. The PINN model with boundary pre-training is the fastest converging method at the current stage.
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