Kohonen's SOM with cache

The Kohonen self-organizing map (SOM),is a topology-preserving map that maps data from higher dimensions onto a (typically) two-dimensional grid of lattice points [1]. The aim of self-organization is to generate a topology-preserving mapping, where the neighborhood relations in the input space are preserved as well as possible, in the neighborhood relations of the units of the map [2]. One of the most time consuming steps during the training of the SOM is the sub-problem of locating the winner node for a given sample. A winner node is the best matching unit for each input vector