https://github.com/fusion809/simplex

Linear programme solver that uses the simplex method. Has advanced features and shows full working.
https://github.com/fusion809/simplex

linear-programming-solver operations-research sensitivity-analysis simplex simplex-algorithm simplex-method

Last synced: 2 months ago
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Linear programme solver that uses the simplex method. Has advanced features and shows full working.

• Host: GitHub
• URL: https://github.com/fusion809/simplex
• Owner: fusion809
• License: gpl-3.0
• Created: 2020-10-24T11:41:17.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2023-09-22T08:37:00.000Z (over 1 year ago)
• Last Synced: 2023-09-23T04:37:14.948Z (over 1 year ago)
• Topics: linear-programming-solver, operations-research, sensitivity-analysis, simplex, simplex-algorithm, simplex-method
• Language: JavaScript
• Homepage: https://fusion809.github.io/simplex/
• Size: 187 KB
• Stars: 5
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Simplex method solver

This repository contains a webpage I have written to solve linear programmes using the simplex method. 

As of 19 November 2020 this solver:

* Prints messages indicating whether the solution is:

  * Permanently degenerate.

  * Permanently infeasible.

  * Unbounded.

* Prints the final solution, including decision variable values, dual variable values and objective function value.

* Mentions whether a problem has alternate solutions and lists them.

* Shows extensive working.

* Uses USQ's [MAT2200](https://www.usq.edu.au/course/synopses/2020/MAT2200.html) simplex tableau layout (not sure the formal name for this layout).

* Can perform sensitivity analysis, including:

  * The adding of new constraint(s).

  * The changing of objective function coefficient(s).

  * The change in resource value(s) (the right-hand side of constraints).

  * Constraint left-hand side change(s).

  * The adding of new variable(s).

* Allows the user to enter the problem in either matrix form or non-matrix form.

Shortcomings include:

* Poor performance. For really big problems this solver is *very slow* (taking several seconds). Performance has been improved to an extent by reducing redundancy. Any optimizations will be welcome.

* Does not solve integer programming problems (BB.js is an attempt at this, but it was abandoned due to the complexity of the recursion required).

* While the original problem can be entered in non-matrix form, sensitivity analysis can only be performed with changes to the problem entered in matrix form.