arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1406.4775cs.ITmath.ITmath.STstat.TH
收藏

非负主成分分析:消息传递算法和尖锐渐近性

Non-negative Principal Component Analysis: Message Passing Algorithms and Sharp Asymptotics

Andrea Montanari, Emile Richard

摘要:

主成分分析(PCA)旨在估计高维数据集的最大变异方向。一个自然的问题是:当我们利用关于主向量的额外知识时,这项任务是否变得更容易,估计是否更准确?我们研究的情况下,其中的主向量是已知的谎言,在正正交。类似的限制出现在许多应用中,从基因表达数据的分析到神经信号处理中的尖峰排序。在不受约束的情况下,PCA的估计性能已被精确地使用随机矩阵理论的特点,在一个被称为“尖峰模型”的统计模型。众所周知,当信噪比超过某个阈值时,估计误差经历相变。不幸的是,随机矩阵理论的工具对约束问题没有影响。尽管存在这一挑战,我们开发了一个类似的表征在约束的情况下,在一个尖峰模型。特别是:$(i)$ ~我们证明了--与无约束情况不同--估计误差依赖于尖峰向量,并描述了最不利向量的特征; $(iii)$ ~我们证明了非负主成分可以近似计算-在尖峰模型下-在接近线性的时间内。尽管这个问题是非凸的,而且一般来说,NP-难以精确解决。

英文摘要:

Principal component analysis (PCA) aims at estimating the direction of maximal variability of a high-dimensional dataset. A natural question is: does this task become easier, and estimation more accurate, when we exploit additional knowledge on the principal vector? We study the case in which the principal vector is known to lie in the positive orthant. Similar constraints arise in a number of applications, ranging from analysis of gene expression data to spike sorting in neural signal processing. In the unconstrained case, the estimation performances of PCA has been precisely characterized using random matrix theory, under a statistical model known as the `spiked model.' It is known that the estimation error undergoes a phase transition as the signal-to-noise ratio crosses a certain threshold. Unfortunately, tools from random matrix theory have no bearing on the constrained problem. Despite this challenge, we develop an analogous characterization in the constrained case, within a one-spike model. In particular: $(i)$~We prove that the estimation error undergoes a similar phase transition, albeit at a different threshold in signal-to-noise ratio that we determine exactly; $(ii)$~We prove that --unlike in the unconstrained case-- estimation error depends on the spike vector, and characterize the least favorable vectors; $(iii)$~We show that a non-negative principal component can be approximately computed --under the spiked model-- in nearly linear time. This despite the fact that the problem is non-convex and, in general, NP-hard to solve exactly.

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。

↑