• ## Exercises in Chapter 9 of statistical learning methods

Time：2021-12-2

Exercise 9.1 EM algorithm is divided into E-step and M-step For step e, calculate the expectation.$$\mu_j^{(i+1)} = \frac{\pi^{(i)}(p^{(i)})^{y_j}(1-p^{(i)})^{1-y_j}}{\pi^{(i)}(p^{(i)})^{y_j}(1-p^{(i)})^{1-y_j} + (1 – \pi^{(i)})(q^{(i)})^{y_j}(1-q^{(i)})^{1-y_j}}$$ For Step M, the maximum likelihood is estimated.$$\pi^{(i+1)} = \frac{1}{n} \sum \mu_j^{(i+1)}$$ ， $$p^{(i+1)} = \frac{\sum \mu_j^{(i+1)}y_j}{\sum \mu_j^{(i+1)}}$$ ，$$q^{(i+1)} = \frac{\sum (1-\mu_j^{(i+1)})y_j}{\sum (1 – \mu_j^{(i+1)})}$$ First iteration Step e: the observation value is […]

• ## How to solve the problem of naive Bayesian classification

Time：2021-3-22

Public number: manong charging station Pro Home page:https://codeshellme.github.io Bayes principle is a British mathematicianThomas BayesIt was proposed in the 18th century that when we can’t directly calculate the possibility of the occurrence of a thing (a), we can indirectly calculate the possibility of the occurrence of the things (x, y, z) related to this thing, […]

• ## Naive Bayes classification theory how to solve classification problem by probability

Time：2021-3-21

Public number: manong charging station Pro Home page:https://codeshellme.github.io Bayes principle is a British mathematicianThomas BayesIt was proposed in the 18th century that when we can’t directly calculate the possibility of the occurrence of a thing (a), we can indirectly calculate the possibility of the occurrence of the things (x, y, z) related to this thing, […]

• ## Interview questions: n schemes of converting pseudo array to array

Time：2021-3-20

I interviewed a person today, but I didn’t know how to make itPseudo array to array？ What is a pseudo array? yeslengthProperty, and it is also an object with numeric subscripts. NoArray.prototypeThe method on the Internet Common pseudo array arguments document.getElementsByClassName \$(‘div’) Pseudo array to array Output pseudo array function fun(a,b,c = 1){ arr = […]

• ## Topic series block 1

Time：2020-12-7

New topic of get Come and write a blog In fact, this is what I have said before… I didn’t listen to it carefully… Now I can understand Sequence block board questions – LOJ 6277 introduction to block 1 Link up- https://loj.ac/problem/6277 The problem surface is very simple – interval addition of series, single point […]

• ## A simple VBS class instance code

Time：2020-11-10

class CFoo     sub PrintHello()         response.Write “Hello World!”     end sub end class dim obj set obj = new CFoo  call obj.PrintHello set obj = nothing

• ## Implementation of a simple calculator based on JSP

Time：2020-7-30

This paper describes the method of implementing a simple calculator based on JSP. Share with you for your reference. The specific implementation method is as follows: index.jsp Copy codeThe code is as follows: <%@ page language=”java” import=”java.util.*” pageEncoding=”GB18030″%>  <%  String path = request.getContextPath();  String basePath = request.getScheme()+”://”+request.getServerName()+”:”+request.getServerPort()+path+”/”;  %>  <html>    <head>  <! — user submitted […]

• ## Some Simple Use Skills of FreeBSD

Time：2019-9-18

1. Archives structure is very important in unix-like, so how do we look at the description of relevant archives directory structure? Is it CD in every directory? In fact, there is a better way. That is to use a good man to see: # man hier 2. When operating under console, because the screen display […]

• ## A Simple Method of Updating Ports Tree

Time：2019-8-23

#vi /etc/protsnap.conf SERVERNAME = portsnap. freebsd. ORG Change to portsnap.tw.freebsd.org # Portsnap fetch # Portsnap extract Until it appears Building new INDEX files…..done.

• ## FreeBSD 5.4 apache-2.0.54+php+Zend Optimizer Simple Installation and Setup

Time：2019-8-18

It is strongly recommended to install with ports. Next, we will post the installation and some simple settings. For other advanced functions, please post and discuss them (please Google first, many questions have already been asked by others).1: Install Apache cd /usr/ports/www/apache2 make install clean; 2: Install PHP4 cd /usr/ports/www/mod_php4 make install clean;Be careful not […]

• ## A Simple Method of Generating XML from Database

Time：2019-5-10

The first example method:1 SqlConnection conn = new SqlConnection(); 2 conn.ConnectionString = “Server=127.0.0.1;User ID=sa;Password=fdahgdrethj31313210212121; Database=northwind;Persist Security Info=True”; 3 conn.Open(); 4 SqlDataAdapter Da = new SqlDataAdapter (“select * from table”, conn);5 SqlCommandBuilder thisBulder = new SqlCommandBuilder(da); 6 DataSet ds = new DataSet(); 7 da.Fill(ds); 8 ds.WriteXml(@”C:\temp.xml”); The second example method:1 private void WriteXmlToFile(DataSet thisDataSet)2 {3 if […]