## Topic C of the 14th "certification Cup" mathematical modeling network challenge in 2021

Background introduction
Since 2015, the shared automobile industry has "let a hundred flowers bloom" and many projects have received huge financing. However, due to the heavy model, high operating costs, inability to make profits and other problems, one after another shared car companies closed down due to the rupture of the capital ...

Posted by **BrentNorin** on *Tue, 08 Mar 2022 08:35:23 +0100*

## Grey correlation and TOPSIS method -- matlab

catalogue
1. Introduction
2. Detailed explanation of algorithm
2.1 index normalization and standardization
2.2} find the maximum and minimum reference vector
2.3} calculate the correlation coefficient with the reference vector
2.4 scoring
3. Case analysis
3.1 reading data
3.2 data standardization
3.3 get the maximum and minimum refere ...

Posted by **warren** on *Thu, 24 Feb 2022 15:48:12 +0100*

## Processing of Python Programming constraints of simulated annealing algorithm

1. Optimization and linear programming
The three elements of optimization problem are decision variables, objective function and constraints.
Linear programming is an optimization method to study the extreme value problem of linear objective function under linear constraints. It is often used to solve the problem of using existing resources t ...

Posted by **Bman900** on *Fri, 18 Feb 2022 14:20:59 +0100*

## Python digital analog notes - NetworkX conditional shortest path

1. Shortest path problem with conditional constraints
The shortest path problem is to find the shortest path between two vertices in graph theory. It is usually to find the shortest weighted path.
Conditional shortest path refers to the shortest path with constraints and restrictions. For example, vertex constraints, including restrictions on ...

Posted by **clio-stylers** on *Wed, 09 Feb 2022 20:34:43 +0100*

## [mathematical modeling] [lingo] basic operation of Lingo

Overall structure
lingo's code is mainly divided into five parts: predefined, data input, objective function, decision variables and constraints.
Note: 1. lingo code needs to start with model and end with end, but in a simple model, both statements can be omitted.
2. A semicolon in English is required after each line of code.
3. lingo is no ...

Posted by **todd-imc** on *Fri, 04 Feb 2022 15:35:45 +0100*

## Mathematical modeling 2020B problem crossing the desert

1. Title
Consider the following small games: players use a map, use the initial funds to buy a certain amount of water and food (including food and other daily necessities), start from the starting point and walk in the desert. In case of different weather on the way, you can also supplement funds or resources in mines and villages. The goal i ...

Posted by **oskom** on *Fri, 04 Feb 2022 10:30:00 +0100*

## knn(k-nearest neighbor algorithm) -- python

catalogue
1. Basic definitions
2. Algorithm principle
2.1 advantages and disadvantages of the algorithm
2.2 algorithm parameters
2.3 variants
3. Distance formula in the algorithm
4. Case realization
4.1 import related libraries
4.2 reading data
4.3 read variable name
4.4 define X,Y data
4.5 separate training set and test set
4.6 ca ...

Posted by **marcusb** on *Sun, 30 Jan 2022 07:06:35 +0100*

## Mathematical modeling in R language: Regression analysis

Some records and summary of learning modeling in the past six months
1, Linear region
For such a data with obvious linear trend, we should find a straight line to make it have the ability to predict the trend of the data, and adopt the least square estimates, that is, the fitted straight line conforms to the criterion of minimizing the su ...

Posted by **ilikephp** on *Thu, 20 Jan 2022 11:36:45 +0100*

## [Python] NBA regular season team ranking based on competition chart method

background
At present, the teams in the NBA regular season are ranked according to the winning rate from high to bottom. This ranking method is very simple and easy to be generally accepted by the public. However, due to the asymmetric cycle of NBA regular season competition system, such ranking rules are not completely fair. Therefore, this p ...

Posted by **rharden** on *Fri, 31 Dec 2021 07:38:34 +0100*

## Learning mathematical modeling (10): complete solution of function is very important!! so I'll talk about it again carefully! Novice suggestions collection.

preface
Why did I talk about functions once before and I have to talk about them again now? The first reason is that I said too little before. The second reason is that functions are very important! Very important! Very important! Say something important three times. After all, I started to write a quick start, which is inevitably missing ...

Posted by **jasonscherer** on *Fri, 24 Dec 2021 05:09:50 +0100*