Research Article

The New and Computationally Efficient MIL-SOM Algorithm: Potential Benefits for Visualization and Analysis of a Large-Scale High-Dimensional Clinically Acquired Geographic Data

Algorithm 1

Presents the pseudocode for the MIL-SOM (Mathematically Improved Learning) Algorithm.
The MIL-SOM algorithm for training a 2-dimensional map is defined as follows:
Let
   X be the set of n training patterns
   W be a grid of units where and are their coordinates on that grid
    be the best clustering after iterations where is the distance between all
   possible pairs of neural nodes and data points
   alpha be the original learning rate, assuming values in (0,1) initialized to a
   given initial learning rate
   alpha1 alpha*a1 be the first improved learning rate
   alpha2 alpha*a2 be the second improved learning rate
   a1 be the first nonnegative parameter of alpha1 when set to zero it yields the original SOM update
   a2 be the second nonnegative parameter of alpha2 when set to zero it also yields the original SOM update
   diff is the differentiation for
   int is the integral term for with intervals 0 to (1 to
    ).
   radius be the radius of the neighborhood function H ,
   initialized to a given initial radius
Repeat
   for to
      for all , calculate absolute distance
   for up to number_iteration
      Calculate the sum of the distances between all possible pairs of
      neural nodes and data points
      Select the unit that minimizes as the winning neuron
      Iterate to minimize the quantization and topological errors and select
      the best SOM cluster with minimum
—Standard SOM used to Update each unit H
      Define , as syms ,
      Apply improved procedure to Update each unit
       ( ((alpha* +(alpha1*(diff ))+(alpha2*(int(( ),0, )))))));
—Note will tend in the direction of zero as learning improves
—Decrease the value of alpha, alpha1, alpha2, and radius
—Until alpha, alpha1, and alpha2 reach 0
—Visualize output of MIL-SOM* using the distance matrix, e.g., -Matrix