https://blog.youkuaiyun.com/u011467621zh-cnhttps://blog.youkuaiyun.com/https://blog.youkuaiyun.com/u011467621/article/details/111879418https://blog.youkuaiyun.com/u011467621/article/details/111879418u011467621Tue, 29 Dec 2020 08:39:31 +0800https://blog.youkuaiyun.com/u011467621/article/details/111496844https://blog.youkuaiyun.com/u011467621/article/details/111496844u011467621Mon, 21 Dec 2020 20:22:46 +0800https://blog.youkuaiyun.com/u011467621/article/details/105980747https://blog.youkuaiyun.com/u011467621/article/details/105980747u011467621Thu, 07 May 2020 20:27:59 +0800https://blog.youkuaiyun.com/u011467621/article/details/105146687https://blog.youkuaiyun.com/u011467621/article/details/105146687u011467621Fri, 27 Mar 2020 17:58:21 +0800https://blog.youkuaiyun.com/u011467621/article/details/105032059https://blog.youkuaiyun.com/u011467621/article/details/105032059u011467621Sun, 22 Mar 2020 18:08:25 +0800https://blog.youkuaiyun.com/u011467621/article/details/100065071https://blog.youkuaiyun.com/u011467621/article/details/100065071u011467621Sun, 25 Aug 2019 17:04:58 +0800https://blog.youkuaiyun.com/u011467621/article/details/99698871https://blog.youkuaiyun.com/u011467621/article/details/99698871u011467621Sat, 17 Aug 2019 22:28:57 +0800https://blog.youkuaiyun.com/u011467621/article/details/90172935https://blog.youkuaiyun.com/u011467621/article/details/90172935u011467621Mon, 13 May 2019 14:31:28 +0800https://blog.youkuaiyun.com/u011467621/article/details/85037944https://blog.youkuaiyun.com/u011467621/article/details/85037944u011467621Sun, 16 Dec 2018 16:09:53 +0800https://blog.youkuaiyun.com/u011467621/article/details/84675730https://blog.youkuaiyun.com/u011467621/article/details/84675730u011467621Sat, 01 Dec 2018 17:27:27 +0800https://blog.youkuaiyun.com/u011467621/article/details/79108980https://blog.youkuaiyun.com/u011467621/article/details/79108980u011467621Fri, 19 Jan 2018 17:17:48 +0800https://blog.youkuaiyun.com/u011467621/article/details/52244285https://blog.youkuaiyun.com/u011467621/article/details/52244285u011467621Thu, 18 Aug 2016 19:47:53 +0800By joeyqzhou >摘自 重构 Martin Fowler - The first Step in refactoring is to build a solid set of tests - It is vital to make tests self-checking - 更改到更好的变量名是很有意义的 - code that communicates its purpo]]>https://blog.youkuaiyun.com/u011467621/article/details/51540578https://blog.youkuaiyun.com/u011467621/article/details/51540578u011467621Mon, 30 May 2016 19:53:44 +0800=0 若事件x,y相互独立，那么 h(x,y)=−logp(x,y)=−logp(x)p(y)=h(x)+h(y) h(x,y)=-\log p(x,y)=-\log p(x)p(y) = h(x) + h(y) 熵：可以表示某个随机事]]>https://blog.youkuaiyun.com/u011467621/article/details/50450421https://blog.youkuaiyun.com/u011467621/article/details/50450421u011467621Sun, 03 Jan 2016 10:40:59 +0800joey 周琦 现在很多数据处理用的是python或R, 那么现在我们对比下scala和python在大数据处理方面的优劣： - scala与python对比 - scala 相对于c语言慢2-3倍，但是python一般比c语言慢50倍。（只是大概，实际会情况不同） - scala 缺少python那样丰富的数据处理,机器学习的包（Numpy, scipy, matplotl]]>https://blog.youkuaiyun.com/u011467621/article/details/50040427https://blog.youkuaiyun.com/u011467621/article/details/50040427u011467621Wed, 25 Nov 2015 18:01:31 +0800https://blog.youkuaiyun.com/u011467621/article/details/49888467https://blog.youkuaiyun.com/u011467621/article/details/49888467u011467621Tue, 17 Nov 2015 15:46:43 +0800By joey周琦 正则化假设目标函数为JJ, 比如JJ可以是对数似然函数的负数形式，特征ii的系数为wiw_i, 系数向量 w=[w1,...,wK] w = [w_1,...,w_K] ,假设一共有KK个备选类。 机器学习（分类为例）的目标就是要解决一个优化问题 w=argminwL(w) w = \arg \min \limits_w L(w) 而为了避免模型的过拟合(overfitti]]>https://blog.youkuaiyun.com/u011467621/article/details/49685107https://blog.youkuaiyun.com/u011467621/article/details/49685107u011467621Fri, 06 Nov 2015 16:52:52 +0800https://blog.youkuaiyun.com/u011467621/article/details/49281405https://blog.youkuaiyun.com/u011467621/article/details/49281405u011467621Tue, 20 Oct 2015 19:16:40 +0800 By joey周琦 概述 线性模型一般variance小，bias大；而树模型一般variance大，bias小 决策树的优点：具有可读性，分类速度快 一般包含三个步骤： 特征选择 决策树生成 剪枝 决策树定义：分类决策树模型是一种描述对实例进行分类的树形结构。决策树由结点(node)和有向边(directed edge)组成。结点分为内部结点和叶结点，内部结点表示一个特征(feature),]]>https://blog.youkuaiyun.com/u011467621/article/details/48754679https://blog.youkuaiyun.com/u011467621/article/details/48754679u011467621Sat, 26 Sep 2015 21:21:42 +0800https://blog.youkuaiyun.com/u011467621/article/details/48735929https://blog.youkuaiyun.com/u011467621/article/details/48735929u011467621Fri, 25 Sep 2015 17:54:10 +0800