arXiv:2410.06376math.OCcs.LG2024-10被引 7

基于黎曼优化的点定位方法,可保证全局收敛且样本需求更低。

Riemannian Optimization for Non-convex Euclidean Distance Geometry with Global Recovery Guarantees

  • 在低秩矩阵补全框架下,用非正交基表示距离数据
  • 采样数满足 $m \geq \mathcal{O}(nr^2 \log n)$ 时线性收敛到真解
  • 适合需要高精度点云重建的科研与工程场景

从部分距离信息中恢复点的几何构型是应用科学中的基础问题。本文提出两种基于黎曼优化的算法解决欧氏距离几何(EDG)问题。将问题建模为格拉姆矩阵的低秩矩阵补全,利用非正交基下的展开系数表示观测距离。第一种算法在均匀有放回采样下,若采样数 $m \geq \mathcal{O}(n^{7/4}r^2 \log n)$,经一步硬阈值初始化后,黎曼梯度类算法以高概率线性收敛至真解;通过重采样黎曼梯度下降改进初始化后,样本量可降至 $m \geq \mathcal{O}(nr^2 \log n)$。分析依赖于非自伴算子及受限基矩阵内积矩阵的特征值界,结合稀疏性获得更紧约束。第二种算法引入自伴近似采样算子,在合成与真实数据上表现优异。此外,优化高于秩-$r$ 的流形可获得更优数值结果,符合近期关于过参数化在EDG中优势的研究结论。

原文摘要 · Abstract (English)

The problem of determining the configuration of points from partial distance information, known as the Euclidean Distance Geometry (EDG) problem, is fundamental to many tasks in the applied sciences. In this paper, we propose two algorithms grounded in the Riemannian optimization framework to address the EDG problem. Our approach formulates the problem as a low-rank matrix completion task over the Gram matrix, using partial measurements represented as expansion coefficients of the Gram matrix in a non-orthogonal basis. For the first algorithm, under a uniform sampling with replacement model for the observed distance entries, we demonstrate that, with high probability, a Riemannian gradient-like algorithm on the manifold of rank-$r$ matrices converges linearly to the true solution, given initialization via a one-step hard thresholding. This holds provided the number of samples, $m$, satisfies $m \geq \mathcal{O}(n^{7/4}r^2 \log(n))$. With a more refined initialization, achieved through resampled Riemannian gradient-like descent, we further improve this bound to $m \geq \mathcal{O}(nr^2 \log(n))$. Our analysis for the first algorithm leverages a non-self-adjoint operator and depends on deriving eigenvalue bounds for an inner product matrix of restricted basis matrices, leveraging sparsity properties for tighter guarantees than previously established. The second algorithm introduces a self-adjoint surrogate for the sampling operator. This algorithm demonstrates strong numerical performance on both synthetic and real data. Furthermore, we show that optimizing over manifolds of higher-than-rank-$r$ matrices yields superior numerical results, consistent with recent literature on overparameterization in the EDG problem.

几何重构黎曼优化矩阵补全

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