Launch WebSim

Introduction

WebSim is a program that uses the simplex method to solve Linear Optimization Problems.

Browser Requirements - WebSim is developed and tested in Mozilla browsers (Firefox and Camino), but should work the same in Internet Explorer and Safari. For best results, make sure you are running Firefox version 1.5.0.4 or later. This can be downloaded from mozilla.com.

Because WebSim tends to open a lot of windows if you have multiple tableaux open, it's best to use a browser that supports 'tabbed browsing'. In Firefox, go to the menu Tools > Options, select Advanced and click on Tabbed Browsing. Select Force links that open new windows to open in: and select a new tab.

If you discover any bugs with the way WebSim works, please send a detailed email to jake.hawkes@gmail.com

Download WebSim - Due to overwhelming popular demand, WebSim is available for download. Simply download the downloadable version, unzip it, and open the file "tableau.html" in a browser.


The Basics

To begin, click on the "Launch WebSim" link in the upper right hand corner. This will pop up a new tab with a simple form, prompting you to choose whether the problem consists of inequalities or equalities. A third option, "Empty", allows you to simply paste an existing tableau that you might have copied from Maple or a word processing program.

After you have selected the type of equations in your problem, a few more prompts show up. One of these allows you to choose whether the problem is a linear optimization problem (LOP) or a system of equations. The only difference between the two types of problems is that a LOP will contain a 'Z-column' and an objective row, whereas a system will not. You are also prompted to enter the number of variables and constraints in the problem, after which you should click "Done".

At this point a table pops up with the slack variables filled in (and the Z-column as well if the problem is a LOP). The table of numbers in the middle represents a tableau which can be edited or pivoted on at any time. The buttons to the left and above the tableau are used for popping up menus. In order to pop-up a menu, simply right-click any button or entry. The button above and to the left is called the "tableau button", the buttons directly above the tableau are called "column buttons", and the buttons directly to the left of the tableau are called "row buttons".

Pivoting can be accomplished simply by double-clicking on the entry on which you wish to pivot. The resulting tableau will appear beneath the current tableau, and the page will automatically scroll to show only the resulting tableau.


The Menus!

There are four different menus.

Entry Menu

Column Menu

Row Menu

Tableau Menu