• ## Based on the source, grasp the law

Time：2022-5-5

“Multiplication distribution law” is an important operation law in primary school, which is used in the solution of many problems. “Multiplication distribution law” is the knowledge basis for learning algebraic simplification and formula induction in the future, which has important value and position in mathematics learning. Its biggest difference from multiplication exchange law and combination […]

• ## draft

Time：2022-5-1

Hello, children. I’m your teacher Yi. Let’s learn the double insertion problem together today. [1.9 seconds] let’s take a look at the topic first. After moving the decimal point of a number to the right by one digit, the number obtained is 108 more than the original number. What is the original number? After reading […]

• ## Load test, concurrent test and stress test

Time：2022-4-15

Load test 1. Definition:Load test is to test the change of system performance by gradually increasing the system load, and finally determine the maximum load that the system can bear under the condition of meeting the performance index. 2. Purpose:The test without hanging the system enables the system to operate normally under the maximum pressure. […]

• ## Re cognition of Euler formula

Time：2022-4-12

Through the deformation of Euler formula, e ^ I π = – 1 is obtained. e. I and π are uncertain, while – 1 is certain. Then, for the derivation of Euler formula, from the perspective of mathematics, physics and philosophy, can the relationship between certainty and uncertainty be explained in the following aspects: a. […]

• ## Calculation algorithm of the shortest distance and line segment of two lines / line segments in three-dimensional space

Time：2022-4-11

There are two space segments \$L_ S \$, whose starting and ending coordinates are \$s_ 0、s_ 1 \$, direction vector \$\ VEC u = s_ 1-s_ 0 \$ \$L_ T \$, whose starting and ending coordinates are \$t_ 0、t_ 1 \$, direction vector \$\ VEC v = t_ 1-t_ 0 \$Note that the line corresponding […]

• ## Solving assignment problem with programming model

Time：2022-4-3

1、 Foreword    optimization models mainly include linear programming, nonlinear programming, dynamic programming and integer programming. The assignment problem is an important problem in integer programming: have\(n\)Task, by\(n\)Each person can only do one thing\(i\)Personal completion\(j\)Task to\(c_{ij}\)Hours, how to reasonably arrange the time to minimize the total time? 2、 Mathematical model of assignment problem We introduce […]

• ## SVD dimension reduction by singular value decomposition

Time：2022-4-1

Dimension reduction unsupervised learning method, singular value decomposition SVD dimension reduction is to reduce an arbitrary n through matrix operation × The matrix A of D is decomposed into the result of multiplication of left singular matrix U, singular value matrix Σ and right singular matrix V, and then the dimension reduction of matrix A […]

• ## Ineuos industrial interconnection platform, revision of equipment container (Internet of things), and real-time calculation and early warning of equipment data points. Release version 3.2

Time：2022-4-1

Catalogue 1. Overview two 2. Platform demonstration two 3. Introduction to the new version of equipment container two 4. Global data calculation and warning platform three 5. Equipment data calculation and early warning four 6. Early warning of independent data points five  1. General This upgrade mainly focuses on the comprehensive revision and upgrade of […]

• ## On dynamic programming and DFS

Time：2022-3-25

preface It is still necessary to learn the algorithm from the front end. Not to mention that the algorithm is tested in the interview of large factories, but when doing the permission module, if you don’t understand the algorithm, you can’t write the user-defined traversal of the tree structure.Today, I will make a summary of […]

• ## Reshape package usage

Time：2022-3-17

Reshape package The reshape package is a wonderful universal tool for refactoring and integrating data. #Installation install.packages(“reshape”) Roughly speaking, you first need to “melt” the data so that each row is a unique identifier variable combination. Then “cast” the data to any shape you want. 1. Integration Each measurement variable has an exclusive row with […]

• ## Feynman learning method is an efficient learning method

Time：2022-3-14

Feynman is a famous physicist who won the Nobel Prize in physics. In my eyes, physicists are highly intelligent and admirable. When I saw Feynman’s learning method, I felt sorry to meet each other late. I think I can apply it to make up lessons for children in the future. Feynman’s learning method sounds confusing, […]

• ## Basic solution method of reinforcement learning (I)

Time：2022-3-12

brief introduction The previous section mainly introduced the basic concepts of reinforcement learning, mainly introducing the strategies, rewards, states and values of reinforcement learning through setting scenarios. After having the basic elements, the task of reinforcement learning is abstracted with the help of Markov decision process, and finally expressed by Behrman equation. This content mainly […]