Advanced Simplex Pivot Tool

For Those Who Really Hate Doing Arithmetic By Hand


Introduction

Below is a java applet that can be used to solve linear programming problems.

Edit the two text fields to specify the number of rows and columns you want and then click on the Go Pivoting button.

A new window will pop up with an empty dictionary having the correct dimensions. You can enter data elements into each text field to define a specfic problem. Alternatively, you can click on generate random problem to quickly get a random problem to play with.

To make a pivot, simply click on the variable-button that you want to pivot around. If you click on a button associated with a zero pivot element, the applet will complain.

Primal infeasible right-hand side coefficients are highlighted in fuscia (after the first pivot) as are dual infeasible cost coefficients. When all the fuscia cells are gone, you have an optimal dictionary.

This applet features an artificial objective row and an artificial right-hand side column, which can be used to guide pivot choices for either a primal or a dual phase one process. When generating a random problem, the coefficients in the artificial row are set to -1. Hence, this row represents a dual feasible objective function. Similarly, the artificial column is initialized to +1 and therefore represents a primal feasible objective. When pivoting, any infeasibilities that occur in these artificial row/columns are highlighted in yellow.

Click here for hints on how to use the applet.

Bugs. This applet works fine when accessed via Netscape3 on most UNIX workstations and it works fine with either Netscape4 or InternetExplorer4 on WindowsNT. Most other browser/platform combinations do not work correctly. The problem seems to be due to bugs in the browser's JAVA interpreter as implemented on the given platform. If you have trouble getting the applet to behave as described above, try finding a different browser/platform combination.