• Last regression algorithm

Time：2022-4-8

Background knowledge required for reading this article: linear regression algorithm and yidui programming knowledge 1、 Introduction    in the previous section, we learned that one method to solve multicollinearity is to regularize the cost function. One regularization algorithm is called ridge regression algorithm. Let’s learn another regularization algorithm-Lasso regression algorithm)1(lasso regression algorithm), the full name […]

• Visual explanation of graph convolution and message passing theory

Time：2022-3-7

This paper will study how to construct graph convolution neural network based on message passing mechanism, and create a model to classify molecules with embedded visualization. Suppose we now need to design drugs to treat some diseases. There is a data set containing drugs that successfully treat the disease and drugs that do not work. […]

• [mindspire: let’s learn machine with little Mi!] Recommendation system

Time：2022-2-19

I haven’t seen you for a week. I miss you very much. Today, little Mi takes you to learn about recommender systems! Recommendation system is a very important application in machine learning, such as a song that is easy to recommend, a shopping list recommended by a treasure, etc. since it should be so extensive, […]

• Machine learning D2 — encoding: summary of coding methods of category variables in machine learning

Time：2022-2-3

This article mainly introduces several types of encoding. The following is a basic classification: What is categorical data When a data is characterized by finite discrete variables, it is divided into nominal, ordinal and continuous; Why encoding After treatment, it can be put into Common encoding types 1. Label Encoding Visual example: • code directly […]

• Discussion on the exercise of computational molecular evolution – Chapter 1

Time：2022-1-23

Recently, I was studying Mr. Yang Ziheng’s computational molecular evolution. For the exercises at the back of each chapter, I may not find the answers on the Internet. Therefore, I put my calculations here. If there are students to discuss together, I will deepen my progress. Because of my limited level of mathematics, many problems […]

• [reprint] learning notes of the essence of linear algebra

Time：2021-11-13

(original title: ten minutes to understand the essence of linear algebra   Author: Great Chen Haoyu) The essence of linear algebra First, let’s talk about the most important thing. What is linear algebra? The essence of linear algebra is actually a transformation in high-dimensional space. Although this sentence is simple, what does it mean. Don’t […]

• Matrix eigenvectors and eigenvalues

Time：2021-10-24

Recently, when learning LDA, we need to calculate eigenvalues and eigenvectors, so we re learned a wave The calculation of eigenvalues is relatively simple in Python, and the linalg calculation of numpy needs to be imported.Linalg is the abbreviation of linear algebra. Import numpy first import numpy as np Randomly generate a matrix A A […]

• Numerical analysis: power iteration and PageRank algorithm

Time：2021-10-17

1. Power iterative algorithm (power method for short) (1) Dominant eigenvalue and dominant eigenvector Known matrix$$\bm{A} \in \R^{n \times n}$$, $$\bm{A}$$The dominant eigenvalue of is$$\bm{A}$$Other eigenvalues (absolute values) of are large eigenvalues$$\lambda$$, if such eigenvalues exist, and$$\lambda$$The relevant eigenvectors are called dominant eigenvectors. (2) Properties of dominant eigenvalues and dominant eigenvectors If a vector is […]

• AI mathematics foundation: singular value and singular value decomposition

Time：2021-5-5

brief introduction Singular value is a very important concept in matrix, which is generally obtained by singular value decomposition. Singular value decomposition is an important matrix decomposition method in linear algebra and matrix theory, which is very important in statistics and signal processing. Before we get to singular values, let’s look at the concept of […]

• Overview of map search system

Time：2021-2-10

Overview of map search system Image search by image refers to searching images with similar content according to image content. Building a map search system needs to solve two key problems: first, extracting image features; second, feature data search engine, that is, building feature data into database and providing the function of similarity search. Image […]

• Advanced learning notes on face recognition

Time：2020-12-8

1、 Face detection 1. Face detection using OpenCV Opencv uses the algorithm of object detection framework named Viola Jones for face detection. Step 1: Download opencv Library pip install opencv-python -i https://pypi.tuna.tsinghua.edu.cn/simple Step 2: find the default pre training weight file 1. Generally, there is a haarcascade in / lib / python3.7/site-packages/cv2/data directory of the […]

• Engineering practice of map search system

Time：2020-11-28

Engineering practice of map search system I wrote an overview before: an overview of image search system. The main problems to be solved in the system are as follows Extracting image feature vector (using eigenvector to represent an image) Similarity calculation of feature vectors (searching for images with similar contents) The corresponding engineering practices are […]