Usage

To begin, click on the Launch link at left. 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. In this case you should enter the value of the basic coefficient, which is set to 1 as the default otherwise.

After you have selected the type of constraints 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 constraints. 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 appears with the slack variable coefficients 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 tab and arrows keys move from one cell to another to allow data entry and editing --- experiment with them to see how they wrap around horizontally and vertically.

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. (Scrolling between tableau can be useful for class discussions when discovering or witnessing patterns. Also, one can scroll up to a prior tableau and pivot on it successfully.) Note that integer arithmetic is used, so that one needs to divide by the basic coefficient in order to calculate curent basic and objective values.

It is also visually useful to draw lines between various rows, to separate constraints from the objective row, for example (and also original constraints from new valid inequalities from cutting planes), and between various columns, to separate problem variables, slack variables, and the b-column. This can be accomplished by clicking on the black lines between the buttons.

Saving a sequence of tableaux is accomplished by saving the page in your browser. Later, when you open that page in your browser you will see the sequence but it is not an active page (you will not be able to pivot or use any buttons).