## Simplex Pivot Tool

### For Those Who Hate Doing Arithmetic By Hand

If the Java applet fails to start due to *Java Security* issues,
click
here.

#### Instructions

This 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.

The *labels* tab allows one to select the labels for the variable names
makig it easy to set up some standard variants of the simplex method.
If the *dual* labels are chosen and the *seed* value is nonzero,
then the matrix entries will be the negative transpose of the values one
would get with *primal* labels.

The *seed* value controls how random problems are generated.
With the default value of zero, the random number generator is seeded according
to the system clock. Specifying a nonzero seed value gives random problems that
can be repeated by starting over with the same seed value.

Click here for a fancier version of the
pivot tool which includes artificial primal and dual objectives that enable
one to do two phase methods directly with the tool.

**
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.