Class: Cluster::AddC

Inherits:
Object
  • Object
show all
Defined in:
lib/lite/cluster.rb

Instance Method Summary collapse

Constructor Details

#initialize(upperBoundOnNumClusters) ⇒ AddC

Returns a new instance of AddC.



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# File 'lib/lite/cluster.rb', line 5

def initialize( upperBoundOnNumClusters )
  @k_max = upperBoundOnNumClusters
  @centroids = []      
end

Instance Method Details

#centroids(min_num_instances_in_cluster = 2) ⇒ Object 



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# File 'lib/lite/cluster.rb', line 45

def centroids( min_num_instances_in_cluster = 2 )      
  @centroids.each do |c|        
    next if c.n >= min_num_instances_in_cluster
    @centroids = @centroids - [ c ]      
    next if c.n == 0
    aux = @centroids.inject( {:min_c => @centroids.first, :d => @centroids.first.x.dist( c.x )} ) {|a,cc| cc.nil? || cc.x.dist(c.x) > a[:d] ? a : { :min_c=>cc, :d=>cc.x.dist(c.x)} }        
    aux[:min_c].merge! c        
  end
  @centroids
end

#observe!(instance) ⇒ Object 



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# File 'lib/lite/cluster.rb', line 10

def observe!( instance )
  u = SparseVector.new instance

  if @centroids.size == 0
    @centroids << Centroid.new( u )
    return self
  end

  @centroids.sort! {|c1, c2|  u.dist(c1.x) <=> u.dist(c2.x) }
  closest_centroid = @centroids.first
  closest_centroid.update!( u )

  if( @centroids.size >= @k_max ) 
    pairs = [] 
    @centroids.each_index do |i|
      min_d = 10**20
      min_c = 0          
      @centroids.each_index do |j|
        next if i==j
        d = @centroids[i].x.dist( @centroids[j].x )
        min_c = j if d < min_d
        min_d = d if d < min_d
      end
      pairs[i] = [ min_d, i, min_c]
    end
    pairs.sort! {|x,y| x[0]<=>y[0]}
    merge_info = pairs.first
    @centroids[merge_info[1]].merge!( @centroids[merge_info[2]] )
    @centroids = @centroids - [ @centroids[merge_info[2]] ]
  end
  @centroids << Centroid.new( u )
  
  []
end