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arXiv 2409.08862math.NAcs.NA
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集成卡尔曼反演的基本子空间

The Fundamental Subspaces of Ensemble Kalman Inversion

Elizabeth Qian, Christopher Beattie

AI总结:

本文针对线性观测算子,通过直接分析离散EKI迭代,定义了六个基本子空间,从而解释并验证了EKI的收敛性质,并提供了新的收敛行为描述,数值实验验证了理论结果。

摘要:

集成卡尔曼反演(EKI)方法是一类用于求解加权最小二乘问题的迭代方法,特别是那些在科学和工程反问题中出现的,通过最小化数据失配的加权平方范数,从观测数据中估计未知参数或状态的问题。EKI的实现仅需评估将未知量映射到数据的正演模型,而不需要正演模型的导数或伴随。因此,在反问题设置中,当评估正演模型的导数或伴随在计算上难以处理时,这些方法为基于梯度的优化方法提供了一种有吸引力的替代方案。本文针对线性观测算子,对基本EKI的确定性和随机版本的行为进行了新的分析,从而以类似于线性代数中Strang的基本子空间的“基本子空间”术语,对EKI的收敛性质进行了自然解释。我们的分析直接考察离散的EKI迭代,而非先前分析中考虑的连续时间极限,并提供了谱分解,定义了跨越观测空间和状态空间的EKI的六个基本子空间。这种方法验证了先前为连续时间极限推导的收敛速率,并产生了新结果,描述了确定性和随机EKI相对于标准最小范数加权最小二乘解的收敛行为,以基本子空间表示。数值实验验证了我们的理论结果。

英文摘要:

Ensemble Kalman Inversion (EKI) methods are a family of iterative methods for solving weighted least-squares problems, especially those arising in scientific and engineering inverse problems in which unknown parameters or states are estimated from observed data by minimizing the weighted square norm of the data misfit. Implementation of EKI requires only evaluation of the forward model mapping the unknown to the data, and does not require derivatives or adjoints of the forward model. The methods therefore offer an attractive alternative to gradient-based optimization approaches in inverse problem settings where evaluating derivatives or adjoints of the forward model is computationally intractable. This work presents a new analysis of the behavior of both deterministic and stochastic versions of basic EKI for linear observation operators, resulting in a natural interpretation of EKI's convergence properties in terms of ``fundamental subspaces'' analogous to Strang's fundamental subspaces of linear algebra. Our analysis directly examines the discrete EKI iterations instead of their continuous-time limits considered in previous analyses, and provides spectral decompositions that define six fundamental subspaces of EKI spanning both observation and state spaces. This approach verifies convergence rates previously derived for continuous-time limits, and yields new results describing both deterministic and stochastic EKI convergence behavior with respect to the standard minimum-norm weighted least squares solution in terms of the fundamental subspaces. Numerical experiments illustrate our theoretical results.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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