皮尔森相关系数定义: 协方差与标准差乘积的商. Pearson's correlation coefficient when applied to a population is commonly represented by the Greek letter ρ (rho) and may be referred to as the population correlation coefficient or the population Pearson correlation coeffici…
概述: 余弦相似度 是对两个向量相似度的描述,表现为两个向量的夹角的余弦值.当方向相同时(调度为0),余弦值为1,标识强相关:当相互垂直时(在线性代数里,两个维度垂直意味着他们相互独立),余弦值为0,标识他们无关. Cosine similarity is a measure of similarity between two vectors of an inner product space that measures the cosine of the angle between them.…
Large-scale Parallel Collaborative Filtering for the Netflix Prize http://www.hpl.hp.com/personal/Robert_Schreiber/papers/2008%20AAIM%20Netflix/netflix_aaim08(submitted).pdf MATRIX FACTORIZATION TECHNIQUES FOR RECOMMENDER SYSTEMS http://www2.resear…
1. 定义 协同过滤(Collaborative Filtering)有狭义和广义两种意义: 广义协同过滤:对来源不同的数据,根据他们的共同点做过滤处理. Collaborative filtering (CF) is a technique used by some recommender systems.[1] Collaborative filtering has two senses, a narrow one and a more general one.[2] In general,…
数学定义[编辑] 若k个随机变量.--.是相互独立,符合标准正态分布的随机变量(数学期望为0.方差为1),则随机变量Z的平方和 被称为服从自由度为 k 的卡方分布,记作 Definition[edit] If Z1, ..., Zk are independent, standard normal random variables, then the sum of their squares, is distributed according to the chi-squared distrib…
定义: In statistical surveys, when subpopulations within an overall population vary, it is advantageous to sample each subpopulation (stratum) independently.Stratification is the process of dividing members of the population into homogeneous subgroups…
[注]该系列文章以及使用到安装包/测试数据 可以在<倾情大奉送--Spark入门实战系列>获取 .机器学习概念 1.1 机器学习的定义 在维基百科上对机器学习提出以下几种定义: l“机器学习是一门人工智能的科学,该领域的主要研究对象是人工智能,特别是如何在经验学习中改善具体算法的性能”. l“机器学习是对能通过经验自动改进的计算机算法的研究”. l“机器学习是用数据或以往的经验,以此优化计算机程序的性能标准.” 一种经常引用的英文定义是:A computer program is said t…
val path = "/usr/data/lfw-a/*" val rdd = sc.wholeTextFiles(path) val first = rdd.first println(first) val files = rdd.map { case (fileName, content) => fileName.replace("file:", "") } println(files.first)println(files.coun…
