andrew ng machine learning course

dimension.Finally, we propose a method for solving overfitting, including data cleaning/pruning, data hinting, regularization (regularization), confirmation (validation), andTo drive for example to illustrate the role of these methods, the latter two methods are also the contents of the following two lessons.Data cleaning/pruning is to correct or delete the wrong sample points, processing is simple, but usually such sample points are not easy to find.Data hinting generate more sample numbers by

This section is about regularization, in the optimization of the use of regularization, in class when the teacher a word, not too much explanation. After listening to this class,To understand the difference between a good university and a pheasant university. In short, this is a very rewarding lesson.First of all, we introduce the reason for regularization, simply say that the complex model with a simple model to express, as to how to say, there is a series of deduction hypothesis, very creative

Netfei is a DVD leasing company. by increasing its sales by 10%, it can earn 1 million RMB in revenue, which is very impressive. How to: predict consumers' ratings for movies? (Increase the predicted value by 10 percentage points through their own systems) if the recommendations you provide to consumers are very accurate, the consumers will be very satisfied. The essence of machine learning: 1. An existin

represent the right side of the inequality and Delta to represent ε. So we have: We have previously studied the probability of occurrence of bad events. Now let's look at the probability of occurrence of optimistic events: P [| ein (G)-eout (G) | Use Ω (n, H, Delta) instead of ε to get the desired good event definition: | eout-Ein | Ω is positively related to N, Delta, and h or VC. We ignore the Ω parameter first, so there are: | eout-Ein | In most cases, eout is larger than EIN, because w

+ 1 parameter: x0 -- x256. We hope to use machine learning to determine the values of all these parameters. However, with so many parameters, machine learning may take a lot of time to complete, and the effect is not necessarily good. We can see that some pixels are not needed, so we should extract some features from

Translator Note : This article is translated from the Stanford cs231n Course Note convnet notes, which is authorized by the curriculum teacher Andrej Karpathy. This tutorial is completed by Duke and monkey translators, Kun kun and Li Yiying for proofreading and revision.The original text is as follows Content list: structure Overview A variety of layers used to build a convolution neural networkThe dimension setting regularity of the arrangement law l

=[] For C in Cs: # Select Model CLS = Logisticregression (c=c) # submit data to Model training Cls.fit (X_train, Y_train) Scores.append (Cls.score (X_test, Y_test)) # # Drawing Fig=plt.figure () Ax=fig.add_subplot (1,1,1) ax.pl OT (cs,scores) ax.set_xlabel (r "C") Ax.set_ylabel (r "Score") Ax.set_xscale (' Log ') Ax.set_title ("Logisticregression") plt.show () If __name__== ' __main__ ': X_train,x_test,y_train,y_test=load_data () # Generates a dataset for regression problems Test_logist

hypothesis closest to F and F. Although it is possible that a dataset with 10 points can get a better approximation than a dataset with 2 points, when we have a lot of datasets, then their mathematical expectations should be close and close to F, so they are displayed as a horizontal line parallel to the X axis. The following is an example of a learning curve: See the following linear model: Why add noise? That is the interference. The purpose is to

Hope to learn the gospel of the Children of Learning machine, the world's largest AI company Google launched a "machine learning Crash Course", not only the whole Chinese, but also free to listen to OH. The course is 15 hours, th

Public Course address:Https://class.coursera.org/ml-003/class/index INSTRUCTOR:Andrew Ng 1. Model Representation ( Model Creation ) Consider a question: what if we want to predict the price of a house in a given area based on the house price and area data? In fact, this is a linear regression problem. The given data is used as a training sample to train it to get a model that represents the relations

I've been talking about why machines can learn, and starting with this lesson are some basic machine learning algorithms, i.e. how machines learn.This lesson is about linear regression, starting with the minimization of Ein, introducing the Hat Matrix to understand the geometric meaning. Finally, the linear regression and binary classification are compared, and the reason why linear regression can be used t

ADD1 () DROP1 () 9. Regression Diagnostics Does the sample conform to the normal distribution? Normality test: function shapiro.test (X$X1) The distribution of normality Learning set/Is there outliers? How to find Outliers is the linear model reasonable? Maybe the relationship between nature is more complicated. Whether the error satisfies the independence, equal variance (the error is no

This is what we have learned (except decision tree)Here is a typical decision tree algorithm, with four places to choose from:Then introduced a cart algorithm: By decision Stump divided into two categories, the criterion for measuring subtree is that the data are divided into two categories, the purity of these two types of data (purifying).The following is a measure of purity:Finally, when to stop:Decision tree may be overfitting, reducing the number of Ein and leaves (indicating the complexity

In this section, a linear model is introduced, and several linear models are compared, and the linear regression and the logistic regression are used for classification by the conversion error function.More important is this diagram, which explains why you can use linear regression or a logistic regression to replace linear classificationThen the stochastic gradient descent method is introduced, which is an improvement to the gradient descent method, which greatly improves the efficiency.Finally

Public Course address:Https://class.coursera.org/ml-003/class/index INSTRUCTOR:Andrew Ng 1. Motivation 1: Data Compression ( Motivation 1- Data Compression ) The so-called data compression is to reduce the dimension of high-dimensional data, thus reducing the data storage capacity. As for the reason for data compression, it is obvious that the data volume is too large. Let's take a look at the fo

Public Course address:Https://class.coursera.org/ml-003/class/index INSTRUCTOR:Andrew Ng 1. The problem of overfitting ( Over-fitting ) Back to the linear regression problem that we first mentioned to predict the relationship between housing prices and housing area, the simplest model is linear relationship, but in many cases the offline relationship is not applicable, we need to introduce level 2, l

columnsHttps://zhuanlan.zhihu.com/p/20878530?refer=intelligentunit Stanford cs231n Course Assignment # 1 Introduction-Smart Unit-Know the columnhttps://zhuanlan.zhihu.com/p/21441838 Stanford cs231n Course Assignment # 2 Introduction-Smart Unit-Know the columnhttps://zhuanlan.zhihu.com/p/21941485 Stanford cs231n Course Assignment # 3 Introduction-Smart Unit-Know

. DrawingT=[0:0.01:0.98]Y1=sin (2*pi*t)Plot (t,y1) % drawingOnY2=cos (2*pi*t)Plot (T,y2, ' R ')Xlabel (' time ')Ylabel (' value ')Legend (' Sin ', ' cos ') % legendTitle (' My Plot ')Print-dpng ' myplot.png ' % saved as picture fileClose % Closes the current diagramFigure (1) % Create a diagramCLF % Empty chart Current ContentsSubplot (1,2,2) % graph cut to 1*2 grid, draw 2nd gridAxis ([0.5 1-1 1]) % axis changed to x belongs to [0.5,1],y belonging to [ -1,1]Imagesc (The Magic ()), Colorbar,colo