Artificial neural networks Day 05

For SOM training, the weight vector associated with each neuron moves to become the center of a cluster of input vectors. In addition, neurons that are adjacent to each other in the topology should also move close to each other in the input space, therefore it is possible to visualize a high-dimensional
inputs space in the two dimensions of the network topology.

The iris dataset has 4 input attributes. Therefore, There are four elements in each input vector, so the input space is four-dimensional. The weight vectors (cluster centers) fall within this space.

In the below figure, the blue hexagons represent the neurons. The red lines connect neighboring neurons. The colors in the regions containing the red lines indicate the distances between neurons. The darker colors represent larger distances, and the lighter colors represent smaller distances. A band of dark segments crosses from the lower-center region to the upper-right region. The SOM network appears to have clustered the flowers into two distinct groups.



ReferencesMATLAB 2011b Help Documentation