arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.14980math.NAcs.NAmath.OC
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集合卡尔曼反演的自适应正则化方法

Adaptive regularisation for ensemble Kalman inversion

Marco Iglesias, Yuchen Yang

摘要:

我们提出了一个新的正则化策略的经典集合卡尔曼反演(EKI)框架。该战略包括:(i)EKI中更新公式中正则化参数的自适应选择,以及(ii)方案提前停止的标准。与现有的方法相比,我们的参数选择不依赖于额外的调谐参数,这往往有严重的影响EKI的效率。我们激励我们的方法使用的解释EKI作为高斯近似的贝叶斯回火设置反问题。我们表明,我们的参数选择控制连续回火措施之间的对称Kulback-Leibler分歧。我们进一步激励我们的选择使用启发式统计差异原则。我们测试我们的框架,使用电阻抗断层扫描与完整的电极模型。参数化的未知电导率,使我们能够同时平滑或不连续(分段常数)字段。我们数值表明,建议的正则化EKI可以产生有效的,强大的和准确的估计,即使是不连续的情况下,往往需要更大的合奏和更多的迭代收敛。我们比较所提出的技术与标准的选择方法,并证明所提出的方法是一个可行的选择,以解决计算效率的EKI在实际/操作设置。

英文摘要:

We propose a new regularisation strategy for the classical ensemble Kalman inversion (EKI) framework. The strategy consists of: (i) an adaptive choice for the regularisation parameter in the update formula in EKI, and (ii) criteria for the early stopping of the scheme. In contrast to existing approaches, our parameter choice does not rely on additional tuning parameters which often have severe effects on the efficiency of EKI. We motivate our approach using the interpretation of EKI as a Gaussian approximation in the Bayesian tempering setting for inverse problems. We show that our parameter choice controls the symmetrised Kulback-Leibler divergence between consecutive tempering measures. We further motivate our choice using a heuristic statistical discrepancy principle. We test our framework using electrical impedance tomography with the complete electrode model. Parameterisations of the unknown conductivity are employed which enable us to characterise both smooth or a discontinuous (piecewise-constant) fields. We show numerically that the proposed regularisation of EKI can produce efficient, robust and accurate estimates, even for the discontinuous case which tends to require larger ensembles and more iterations to converge. We compare the proposed technique with a standard method of choice and demonstrate that the proposed method is a viable choice to address computational efficiency of EKI in practical/operational settings.

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