提出高效多尺度散点数据插值方法,可处理大规模数据且计算稳定。
Multiscale scattered data analysis in samplet coordinates
- 通过残差递归修正构建多尺度插值,结合不同长度尺度的径向基函数。
- 算法总复杂度为 O(N log²N),对大样本集计算高效且条件数可控。
- 适合处理高维散点数据的插值与逼近,尤其适用于科学计算场景。
本文研究基于全局支持径向基函数(重点为Matérn类)的多尺度散点数据插值方法。通过一系列残差校正构造多尺度近似,将具有不同长度尺度参数的径向基函数组合以捕捉不同层次细节。证明了多尺度系统中对角块的条件数在任意层级下均保持有界,使得可用迭代求解器以固定迭代次数完成数值求解。通过适当的对角缩放,使多尺度系统良好条件化,并据此推导出一般误差估计,约束数值逼近带来的一致性误差。为应用于大规模数据集,建议将每层多尺度系统表示在samplet坐标下。Samplets是具有消失矩的局域离散符号测度,能稀疏逼近广泛类别的径向基函数所生成的广义范德蒙矩阵。对于包含 $N$ 个准均匀数据点的集合,若局部逼近空间维度呈指数衰减,则samplet压缩的多尺度系统可实现 $ ext{O}(N ext{log}^2 N)$ 的组装成本。整体方法总复杂度为 $ ext{O}(N ext{log}^2 N)$。理论结果得到二维与三维空间中的大量数值实验验证。
原文摘要 · Abstract (English)
We study multiscale scattered data interpolation schemes for globally supported radial basis functions with focus on the Matérn class. The multiscale approximation is constructed through a sequence of residual corrections, where radial basis functions with different lengthscale parameters are combined to capture varying levels of detail. We prove that the condition numbers of the the diagonal blocks of the corresponding multiscale system remain bounded independently of the particular level, allowing us to use an iterative solver with a bounded number of iterations for the numerical solution. Employing an appropriate diagonal scaling, the multiscale system becomes well conditioned. We exploit this fact to derive a general error estimate bounding the consistency error issuing from a numerical approximation of the multiscale system. To apply the multiscale approach to large data sets, we suggest to represent each level of the multiscale system in samplet coordinates. Samplets are localized, discrete signed measures exhibiting vanishing moments and allow for the sparse approximation of generalized Vandermonde matrices issuing from a vast class of radial basis functions. Given a quasi-uniform set of $N$ data sites, and local approximation spaces with exponentially decreasing dimension, the samplet compressed multiscale system can be assembled with cost $\mathcal{O}(N \log^2 N)$. The overall cost of the proposed approach is $\mathcal{O}(N \log^2 N)$. The theoretical findings are accompanied by extensive numerical studies in two and three spatial dimensions.
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