此文是斯坦福大学,机器学习界 superstar - Andrew Ng 所开设的 Coursera 课程:Machine Learning 的课程笔记. 力求简洁,仅代表本人观点,不足之处希望大家探讨. 课程网址:https://www.coursera.org/learn/machine-learning/home/welcome Week 2:Linear Regression with Multiple Variables笔记:http://blog.csdn.net/ironyoung…

此文是斯坦福大学,机器学习界 superstar - Andrew Ng 所开设的 Coursera 课程:Machine Learning 的课程笔记. 力求简洁,仅代表本人观点,不足之处希望大家探讨. 课程网址:https://www.coursera.org/learn/machine-learning/home/welcome Week 3: Logistic Regression & Regularization 笔记:http://blog.csdn.net/ironyoung/ar…

##Linear Regression with One Variable Linear regression predicts a real-valued output based on an input value. We discuss the application of linear regression to housing price prediction, present the notion of a cost function, and introduce the gradi…

##Advice for Applying Machine Learning Applying machine learning in practice is not always straightforward. In this module, we share best practices for applying machine learning in practice, and discuss the best ways to evaluate performance of the le…

1. Sigmoid Function In Logisttic Regression, the hypothesis is defined as: where function g is the sigmoid function. The sigmoid function is defined as: 2.Cost function and gradient The cost function in logistic regression is: the gradient of the cos…

一:逻辑回归(Logistic Regression) 背景:假设你是一所大学招生办的领导,你依据学生的成绩,给与他入学的资格.现在有这样一组以前的数据集ex2data1.txt,第一列表示第一次测验的分数,第二列表示第二次测验的分数,第三列1表示允许入学,0表示不允许入学.现在依据这些数据集,设计出一个模型,作为以后的入学标准. 我们通过可视化这些数据集,发现其与某条直线方程有关,而结果又只有两类,故我们接下来使用逻辑回归去拟合该数据集. 1,回归方程的脚本ex2.m: %% Machine…

整理自Adrew Ng 的 machine learning课程week3 目录: 二分类问题 模型表示 decision boundary 损失函数 多分类问题 过拟合问题和正则化 什么是过拟合 如何解决过拟合 正则化方法 1.二分类问题 什么是二分类问题? 垃圾邮件 / 非垃圾邮件? 诈骗网站 / 非诈骗网站? 恶性肿瘤 / 非恶性肿瘤? 用表达式来表示:$y\in\left \{ 0,1 \right \}$, \begin{Bmatrix} 0& : & nagetive &…

1. 机器学习的定义:Machine learning is programming computers to optimize a performance criterion(优化性能标准) using example data or past experience. 2. 监督学习(Supervised Learning):The term supervised learning refers to the fact that we gave the algorithm a data set…

About this Course Machine learning is the science of getting computers to act without being explicitly programmed. In the past decade, machine learning has given us self-driving cars, practical speech recognition, effective web search, and a vastly i…

编程作业文件: machine-learning-ex2 1. Logistic Regression (逻辑回归) 有之前学生的数据,建立逻辑回归模型预测,根据两次考试结果预测一个学生是否有资格被大学录取. 载入学生数据,第1,2列分别为两次考试结果,第3列为录取情况. % Load Data % The first two columns contain the exam scores and the third column contains the label. data = load(…