目录 决策树简单描述 衡量purity的三种方法 Gini Coefficient Entropy熵 决策树简单描述 决策树的样子大概是这个样子的: 选择一个特征作为根节点,把这个特征划分成两个孩子节点,每个孩子节点就是原始数据集的子集,然后再找一个特征作为划分-- 划分的好坏,如图所示: 用纯度Purity来衡量划分的效果,如果划分的好,那么每一个子集都是某一类占据大多数,如果每一个子集都是跟父节点一样的状态,那么就是Low purity. 一个好的划分要满足下面两个特点: 划分是High p…

http://blog.csdn.net/pipisorry/article/details/49445465 海量数据挖掘Mining Massive Datasets(MMDs) -Jure Leskovec courses学习笔记 大规模机器学习之决策树Decision Trees {博客内容:Decision Trees.  This is one of the oldest forms of machine-learning, but there are issues that com…

Decision Trees (DT)是用于分类和回归的非参数监督学习方法. 目标是创建一个模型,通过学习从数据特征推断出的简单决策规则来预测目标变量的值. 例如,在下面的例子中,决策树从数据中学习用一组if-then-else决策规则逼近正弦曲线. 树越深,决策规则越复杂,模型也越复杂. 决策树的优点: 易于理解和解释.树可以被可视化. 需要很少的数据准备.其他技术通常需要数据标准化,需要创建虚拟变量,并删除空白值.但请注意,该模块不支持缺少的值. 使用树(即,预测数据)的成本在用于训练树的数…

https://www.quora.com/Why-do-people-use-gradient-boosted-decision-trees-to-do-feature-transform Why is linearity/non-linearity important?Most of our classification models try to find a single line that separates the two sets of point. I say that they…

python机器学习-乳腺癌细胞挖掘(博主亲自录制视频)https://study.163.com/course/introduction.htm?courseId=1005269003&utm_campaign=commission&utm_source=cp-400000000398149&utm_medium=share CatBoost Enables Fast Gradient Boosting on Decision Trees Using GPUs https://d…

This is the 2nd part of the series. Read the first part here: Logistic Regression Vs Decision Trees Vs SVM: Part I In this part we’ll discuss how to choose between Logistic Regression , Decision Trees and Support Vector Machines. The most correct ans…

Classification is one of the major problems that we solve while working on standard business problems across industries. In this article we’ll be discussing the major three of the many techniques used for the same, Logistic Regression, Decision Trees…

Machine Learning Methods: Decision trees and forests This post contains our crib notes on the basics of decision trees and forests. We first discuss the construction of individual trees, and then introduce random and boosted forests. We also discuss…

Decision Trees are versatile Machine Learning algorithms that can perform both classification and regression tasks,and even multioutput tasks. Decision Trees are the fundamental components of Random Forests,which are among the most powerful Machine L…

一.Table for Content 在之前的文章中我们介绍了Decision Trees Agorithms,然而这个学习算法有一个很大的弊端,就是很容易出现Overfitting,为了解决此问题人们找到了一种方法,就是对Decision Trees 进行 Pruning(剪枝)操作. 为了提高Decision Tree Agorithm的正确率和避免overfitting,人们又尝试了对它进行集成,即使用多棵树决策,然后对于分类问题投票得出最终结果,而对于回归问题则计算平均结果.下面是几条…