在统计中,主成分分析(PCA)是一种通过最大化每个维度的方差来将较高维度空间中的数据投影到较低维度空间中的方法。给定二维,三维或更高维空间中的点集合,可以将“最佳拟合”线定义为最小化从点到线的平均平方距离的线。可以从垂直于第一条直线的方向类似地选择下一条最佳拟合线。重复此过程会产生一个正交的基础,其中数据的不同单个维度是不相关的。 这些基向量称为主成分。

最新论文

We study the problem of approximating orthogonal matrices so that their application is numerically fast and yet accurate. We find an approximation by solving an optimization problem over a set of structured matrices, that we call extended orthogonal Givens transformations, including Givens rotations as a special case. We propose an efficient greedy algorithm to solve such a problem and show that it strikes a balance between approximation accuracy and speed of computation. The approach is relevant to spectral methods and we illustrate its application to PCA.

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