论文标题
中间矩阵完成:从尴尬到最佳
Median Matrix Completion: from Embarrassment to Optimality
论文作者
论文摘要
在本文中,我们考虑矩阵完成,并获得绝对偏差损失,并获得中位矩阵的估计器。尽管中位数有几种吸引人的特性,但非平滑的绝对偏差损失导致大规模数据集的计算挑战,这些数据集越来越普遍。解决大规模问题的一个简单解决方案是并行计算。但是,令人尴尬的平行方式通常会导致效率低下的估计器。基于伪数据的概念,我们提出了一个新颖的改进步骤,该步骤将这种低效率的估计器变成了(接近)最佳矩阵完成程序。精制的估计器是正则中位估计器的近似值,因此不是普通的正则经验风险估计器。这导致对渐近行为的非标准分析。还提供了经验结果以确认所提出的方法的有效性。
In this paper, we consider matrix completion with absolute deviation loss and obtain an estimator of the median matrix. Despite several appealing properties of median, the non-smooth absolute deviation loss leads to computational challenge for large-scale data sets which are increasingly common among matrix completion problems. A simple solution to large-scale problems is parallel computing. However, embarrassingly parallel fashion often leads to inefficient estimators. Based on the idea of pseudo data, we propose a novel refinement step, which turns such inefficient estimators into a rate (near-)optimal matrix completion procedure. The refined estimator is an approximation of a regularized least median estimator, and therefore not an ordinary regularized empirical risk estimator. This leads to a non-standard analysis of asymptotic behaviors. Empirical results are also provided to confirm the effectiveness of the proposed method.