The Kohonen.exe program is a simple program that demonstrates how Kohonen networks organise themselves.
Usually a Kohonen network is used to take input from some source that is to be quantified and diagnosed. However in this program we take our inputs as random points on the surface or inside of a sphere. The reason for this is simply to demonstrate how SONs organise themselves.
When you run the program and create a new document you are presented with some options:
Here you have a choice of 2D or 3D. Selecting 2D means that the random input values are confined to the surface of a sphere and the lattice of weight vectors are 2D. If you select 3D then the values are confined to anywhere within the volume of the sphere and we are working with a 3D weight lattice.
By selecting this option you determine whether the weight lattices are wound around on themselves. I.e. for a lattice with one of the axes with a size of 10 weights, the 10th coordinate has the 9th and 1st weights as neighbours. This means that a 2D lattice has toroidal topology.
These are the dimensions of the weight lattice.
At the beginnning the weights are untrained and are distributed in a 1x1 cube.
When you click Go, the weights organise themselves dependent upon the input values. If you selected the 2D type then you will see the weights arrange themselves on the surface of the sphere.
After a little time, the weights will have organised themselves into a more stable state and should best, given their topological form, have spread themselves as widely as possible across the input values.