## Homogeneity test of covariance matrix (continued from the previous article)

I also know a little about the covariance homogeneity test, but I'm confused if I explain it more. This paper describes the covariance matrix test for two classification problems and the covariance matrix test for multiple classification problems
Homogeneity test of covariance matrix for two classes
Σ 1 is the covariance of category 1, ...

Posted on *Fri, 03 Dec 2021 20:08:45 -0500* by **mastercool**

## Data structure graph theory

DFS
connected
P352 connected component (undirected graph), strongly connected component (directed graph)
pata1034 head of a gang
Core code:
void dfs( int u,int& head,int &numMember,int &totalvalue )//head, numMember and totalvalue change with each recursive dfs, but their final results are subject to the last recursive (without ...

Posted on *Sat, 20 Nov 2021 00:57:06 -0500* by **TimTimTimma**

## 378. The K-th smallest element in an ordered matrix

378. The K-th smallest element in an ordered matrix
Give you an n x n matrix, in which the elements of each row and column are sorted in ascending order to find the k-smallest element in the matrix.
Note that it is the k-th smallest element after sorting, not the k-th different element.
Input: matrix = [[1,5,9],[10,11,13],[12,13,15]], k = 8
...

Posted on *Fri, 19 Nov 2021 19:20:39 -0500* by **apenster**

## How does YOLOv4 train its own dataset

Step 1: install darknet
reference resources: Windows builds Darknet framework environment - yolov4 GPU_ Optimistic lishan blog - CSDN blog
The source code description of darknet has also briefly introduced how to use data sets to train networks
Step 2: create VOC format data set
Collect the data set you need online, or take relevant videos ...

Posted on *Fri, 19 Nov 2021 10:51:42 -0500* by **XeroXer**

## Image preprocessing

Halcon Basics (I)_ leo_888's column - CSDN blog
hom_mat2d_identity (HomMat2DIdentity) Explanation: define an identity matrix with diagonal 1, which is multiplied by any matrix equal to the original matrix itself.
hom_mat2d_translate (HomMat2DIdentity, Tx, Ty, HomMat2DTranslate) Function: add translation to anti fire transformation matrix Homm ...

Posted on *Tue, 09 Nov 2021 20:11:54 -0500* by **rix**

## Collaborative filtering algorithm based on matrix decomposition

Implementation of CF algorithm based on matrix decomposition (I): LFM
LFM is the Funk SVD matrix decomposition mentioned earlier
Analysis of LFM principle
The core idea of LFM (late factor model) implicit semantic model is to contact users and items through implicit features, as shown in the following figure:
P matrix is user lf matri ...

Posted on *Thu, 04 Nov 2021 05:41:34 -0400* by **realchamp**

## Learning summary on September 15

Learning summary on September 15
1, Variable
1. Define multiple variables at the same time
Define multiple variables at the same time and assign the same value: variable name 1 = variable name 2 = variable name 3 =... = data. x = y = z = 0
print(x, y, z)
Define multiple variables at the same time and assign different values: variable nam ...

Posted on *Sat, 16 Oct 2021 01:16:33 -0400* by **gin**

## Figure -- 05 -- greedy algorithm, Prim algorithm, kruskal algorithm

Tip: after the article is written, the directory can be generated automatically. Please refer to the help document on the right for how to generate it
Greedy Algorithm
Greedy algorithm - Definition:
Use the segmentation theorem to find one edge of the minimum spanning tree and repeat until all edges of the minimum spanning tree are ...

Posted on *Sun, 10 Oct 2021 01:26:11 -0400* by **delboy1978uk**

## MATLAB application practice series - nonlinear visualization - nonlinear phase diagram & chaotic system

preface
The following are some boutique columns I have prepared for you. My favorite partners can subscribe by themselves. Your support is the driving force for me to update!
MATLAB-30 days take you from introduction to mastery
Advanced course for in-depth understanding of MATLAB (with source code)
tableau visual data analysis advanced tuto ...

Posted on *Sat, 09 Oct 2021 15:29:51 -0400* by **blacklotus**

## Problem solving [NOIP2013_ match sorting] - problems and transformation

Problem solution_ NOIP2013_ Match sorting
Meaning:
there are two sequences a and B, and the elements of each sequence are different. Any two adjacent elements of any sequence can be interchanged, and it is required to operate the two sequences so that
∑
(
...

Posted on *Fri, 08 Oct 2021 04:03:41 -0400* by **standalone**