• ## CSAPP English Learning Series: Chapter 2: data representation

Time：2021-10-10

Series articles： CSAPP English Learning Series: Preface CSAPP English Learning Series: Chapter 1: a tour of computer systems CSAPP English Learning Series: Chapter 2: data representation CSAPP English Learning Series: Chapter 8: exceptional control flow CSAPP English Learning Series: Chapter 11: network programming CSAPP English Learning Series: Chapter 12: concurrent programming Generally speaking, binary operations […]

• ## [machine learning notes]: boasting linear regression (I)

Time：2021-8-26

Hello, I’m Dongge. As one of the classical regression models in supervised learning, linear regression is a very good start for beginners. Considering the concept of comprehensiveness from a macro perspective, I think we may have been in contact in junior middle school. Y = ax, X is the independent variable, y is the dependent […]

• ## Weighted least squares in Statistical Science

Time：2021-2-20

Today, we will talk about the weighted least squares (WLS), which is based on the ordinary least squares regression (OLS), and is mainly used to solve the heteroscedasticity problem. The general form of OLS is as follows: As we mentioned earlier, OLS has several basic assumptions. One of them is that UI is a random […]

• ## Linear regression: the realization of least square method

Time：2021-1-18

catalog 1、 Linear regression 2、 Least square method 3、 Least square method (vector representation) 4、 Python implementation 1、 Linear regression    given the sample x = (x0, x1, X2,…, xn) described by N attributes,linear modelTry to learn a suitable linear combination of sample attributes to perform the prediction taskf(x) = w1x1 + w2x2 + … […]

• ## Integer ring

Time：2021-1-17

ring Integer ringZ_mIt consists of the following two parts: 1. AssemblyZ_m = ( 0,1,2,…,m )2. Two kinds of operations “+” and “X” make thea, b\in Z_myes: a + b\equiv c\ mod\ m, (c\in Z_m)\\ a\times b\equiv d\ mod\ m, (d\in Z_m) Key features of rings If the result of the addition or multiplication of any […]

• ## CSP-S-2020

Time：2020-11-15

CSP-S-2020 T1 Julian day Give the highest respect (kowtow) to the T1 author. T2 Zoo Give some numbers, guarantee$$x∈[1,2^k-1]$$And different from each other, some conditions are given if there are numbers$$x$$The first$$ai$$Bit is$$1$$Then you have to choose the item$$bi$$，$$bi$$They are different. How many numbers are there$$y$$Satisfaction does not exist$$x=y$$And add$$y$$Post selected$$b$$unchanged. It is easy to […]

• ## On binary (2) – four operations

Time：2020-11-12

(Note:SegmentfaultThe mathematical formula in the article isBUGWhen previewing, it is good. When the article is sent out, it will show that there is a problem. If you have any problem when you read it, you can move on http://www.dubingxuan.com/article/8/ ) Preface In the last article about binary system (1), we spent a lot of space, […]

• ## Using sowteno 2.0

Time：2020-10-29

Tensorflow is Google’s open source artificial intelligence library, which has the most perfect ecological support. It is a necessary tool for the development and scientific research in the field of artificial intelligence.In this paper, under Windows 10, with the help of anaconda, tensorflow 2.0 is installed. tensorflow2.0 install First open anaconda and execute the conda […]

• ## Leetcode 679. 24 point game | Python

Time：2020-10-22

679. 24 point game Source: leetcode https://leetcode-cn.com/problems/24-game subject You have four cards with numbers 1 to 9. You need to determine if you can get 24 by the operation of *, /, +, -, (,). Example 1: Input: [4,1,8,7] Output: true Explanation: (8-4) * (7-1) = 24 Example 2: Input: [1,2,1,2] Output: false be careful: […]

• ## Why normal distribution is so common

Time：2020-8-22

Everyone believes in it (normal distribution): experimenters think it is a mathematical theorem, mathematical researchers think it is an empirical formula.—-Gabriel Lipman This paper is mainly to explain the least squares method, ridge regression and other optimization methods. Normal distribution in life The height of women in life, Let’s say you have 200 blind dates, […]

• ## Least square method and ridge regression lasso regression

Time：2020-8-19

Contents:[TOC] Throw a brick to attract jade If you have just finished a certain exercise, your girlfriend says, “how long are you?”? Then you take a ruler and you want to measure it. Because it is very empty, so the eyes are a little bit dull. After measuring five times, there are five results:18.1cm，17.9cm，18.2cm，17.8cm，18.0cm How […]

• ## Review of basic knowledge of linear algebra

Time：2020-5-18

Review of basic knowledge of linear algebra Machine learning needs some basic knowledge of linear algebra. Matrix: matrix $A= \begin{bmatrix} 1402 & 191\\ 1371 & 821\\ 949 & 1437\\ 147&1448\\ \end{bmatrix}$ $B= \begin{bmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \\ \end{bmatrix}$ A is a$$4\times2$$The matrix of is composed […]