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一种用于迹线范数最小化的加速梯度法

An Accelerated Gradient Method for Trace Norm Minimization
课程网址: http://videolectures.net/icml09_ji_agmt/  
主讲教师: Shuiwang Ji
开课单位: 华盛顿州立大学
开课时间: 2009-08-26
课程语种: 英语
中文简介:
我们考虑通过矩阵变量的跟踪范数规则化的平滑损失函数的最小化。这种公式可用于许多机器学习任务,包括多任务学习,矩阵分类和矩阵完成。针对该问题的标准半定规划方案在计算上是昂贵的。另外,由于跟踪范数的非平滑性,用于解决这类问题的最优一阶黑盒方法收敛为O(1 / sqrt(k)),其中k是迭代计数器。在本文中,我们利用了跟踪范数的特殊结构,在此基础上我们提出了一种收敛为O(1 / k)的扩展梯度算法。我们进一步提出了一种加速梯度算法,该算法实现了平滑问题的最优收敛速度O(1 / k ^ 2)。多任务学习问题的实验证明了所提算法的有效性。
课程简介: We consider the minimization of a smooth loss function regularized by the trace norm of the matrix variable. Such formulation finds applications in many machine learning tasks including multi-task learning, matrix classification, and matrix completion. The standard semidefinite programming formulation for this problem is computationally expensive. In addition, due to the non-smoothness nature of the trace norm, the optimal first-order black-box method for solving such class of problems converges as O(1/sqrt(k)), where k is the iteration counter. In this paper, we exploit the special structure of the trace norm, based on which we propose an extended gradient algorithm that converges as O(1/k). We further propose an accelerated gradient algorithm, which achieves the optimal convergence rate of O(1/k^2) for smooth problems. Experiments on multi-task learning problems demonstrate the efficiency of the proposed algorithms.
关 键 词: 矩阵变量; 平滑损失函数; 跟踪范数
课程来源: 视频讲座网
最后编审: 2019-04-23:lxf
阅读次数: 159