Class: Centroid

Inherits:
Object show all
Defined in:
lib/k_means/centroid.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(position) ⇒ Centroid

Returns a new instance of Centroid.



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# File 'lib/k_means/centroid.rb', line 32

def initialize(position)
  @position = position
end

Instance Attribute Details

#position ⇒ Object

Returns the value of attribute position.



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# File 'lib/k_means/centroid.rb', line 30

def position
  @position
end

Class Method Details

.create_centroids(amount, nodes) ⇒ Object 



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# File 'lib/k_means/centroid.rb', line 4

def create_centroids(amount, nodes)
  ranges = create_ranges(nodes, nodes[0].position.size)
  (1..amount).map do
    position = ranges.inject([]) do |array, range|
      array << rand_between(range[0], range[1])
    end
    new(position)
  end
end

Instance Method Details

#reposition(nodes, centroids) ⇒ Object

Finds the average distance of all the nodes assigned to the centroid and then moves the centroid to that position



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# File 'lib/k_means/centroid.rb', line 38

def reposition(nodes, centroids)
  return if nodes.empty?
  averages = [0.0] * nodes[0].position.size
  nodes.each do |node|
    node.position.each_with_index do |position, index|
      averages[index] += position
    end
  end
  @position = averages.map {|x| x / nodes.size}
end