arXiv:2409.12400math.NAcs.LG2024-09被引 11

用符号距离函数自动编码形状,高效预测任意形状域的物理场解。

Shape-informed surrogate models based on signed distance function domain encoding

  • 通过隐式符号距离函数实现几何形状的自动低维编码。
  • 在任意形状域上预测物理场,精度接近显式参数化最优情况。
  • 无需网格和人工特征提取,适用于拓扑变化场景,适合工程仿真优化。

我们提出一种非侵入式方法构建代理模型,用于逼近参数化偏微分方程(PDE)的解,并能考虑解对计算域形状的依赖性。该方法结合两个神经网络:第一个神经网络基于潜在码生成几何变异性,通过符号距离函数实现隐式几何表示;该自动形状编码技术在潜在空间中生成紧凑、低维的几何表示,无需显式构造编码器。第二个神经网络独立重建每个空间点的物理场输出,避免了传统高维离散化(如计算网格)带来的计算负担。此外,我们发现采用傅里叶特征映射作为神经网络输入可进一步提升几何表征精度。所提方法具有无网格特性,结合潜在空间中的自动特征提取实现降维,兼具高度灵活性与计算效率。该策略无需手动提取几何参数,甚至可应用于拓扑发生变化的情况。流体力学与固体力学领域的数值测试表明,该方法能在任意形状域上准确预测PDE解。结果表明,其精度与显式参数化最优情况相当。

原文摘要 · Abstract (English)

We propose a non-intrusive method to build surrogate models that approximate the solution of parameterized partial differential equations (PDEs), capable of taking into account the dependence of the solution on the shape of the computational domain. Our approach is based on the combination of two neural networks (NNs). The first NN, conditioned on a latent code, provides an implicit representation of geometry variability through signed distance functions. This automated shape encoding technique generates compact, low-dimensional representations of geometries within a latent space, without requiring the explicit construction of an encoder. The second NN reconstructs the output physical fields independently for each spatial point, thus avoiding the computational burden typically associated with high-dimensional discretizations like computational meshes. Furthermore, we show that accuracy in geometrical characterization can be further enhanced by employing Fourier feature mapping as input feature of the NN. The meshless nature of the proposed method, combined with the dimensionality reduction achieved through automatic feature extraction in latent space, makes it highly flexible and computationally efficient. This strategy eliminates the need for manual intervention in extracting geometric parameters, and can even be applied in cases where geometries undergo changes in their topology. Numerical tests in the field of fluid dynamics and solid mechanics demonstrate the effectiveness of the proposed method in accurately predict the solution of PDEs in domains of arbitrary shape. Remarkably, the results show that it achieves accuracy comparable to the best-case scenarios where an explicit parametrization of the computational domain is available.

代理模型符号距离函数无网格方法PDE求解

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