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arXiv 1911.02424math.NAcs.NAmath.OC
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非线性环境下联合卡尔曼反演的Convergence Acceleration

Convergence Acceleration of Ensemble Kalman Inversion in Nonlinear Settings

Neil K. Chada, Xin T. Tong

摘要:

许多数据科学问题可以被公式化为逆问题,其中通过最小化适当的损失函数来估计参数。当涉及复杂的黑盒模型时,通常需要无导数优化工具。集合卡尔曼滤波(EnKF)是一种基于粒子的无导数贝叶斯算法,最初设计用于数据同化。最近,它已被应用到反问题的计算效率。由此产生的算法,称为集合卡尔曼反演(EKI),涉及运行具有EnKF更新规则的粒子集合,因此它们可以收敛到最小值。在这篇文章中,我们研究EKI收敛在一般的非线性设置。为了提高收敛速度和稳定性,我们考虑采用非常数步长和协方差膨胀的EKI。我们证明了EKI可以在非凸的情况下以有限步达到临界点。我们进一步证明了,如果损失函数是强凸的,EKI多项式快速收敛到全局极小。我们验证了两个反问题的数值实验分析。

英文摘要:

Many data-science problems can be formulated as an inverse problem, where the parameters are estimated by minimizing a proper loss function. When complicated black-box models are involved, derivative-free optimization tools are often needed. The ensemble Kalman filter (EnKF) is a particle-based derivative-free Bayesian algorithm originally designed for data assimilation. Recently, it has been applied to inverse problems for computational efficiency. The resulting algorithm, known as ensemble Kalman inversion (EKI), involves running an ensemble of particles with EnKF update rules so they can converge to a minimizer. In this article, we investigate EKI convergence in general nonlinear settings. To improve convergence speed and stability, we consider applying EKI with non-constant step-sizes and covariance inflation. We prove that EKI can hit critical points with finite steps in non-convex settings. We further prove that EKI converges to the global minimizer polynomially fast if the loss function is strongly convex. We verify the analysis presented with numerical experiments on two inverse problems.

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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