Class: BinaryDecisionTree::Node

Inherits:
Object
  • Object
show all
Defined in:
lib/binary_decision_tree/node.rb

Constant Summary collapse

LEFT = 
0
RIGHT = 
1

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(tree, slot) ⇒ Node

Returns a new instance of Node.



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# File 'lib/binary_decision_tree/node.rb', line 11

def initialize(tree, slot)
  @tree = tree
  @slot = slot
  @decision = nil
end

Instance Attribute Details

#decision ⇒ Object

nil, 0, or 1



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# File 'lib/binary_decision_tree/node.rb', line 6

def decision
  @decision
end

#slot ⇒ Object (readonly)

bit position



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# File 'lib/binary_decision_tree/node.rb', line 8

def slot
  @slot
end

#tree ⇒ Object (readonly)

Returns the value of attribute tree.



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# File 'lib/binary_decision_tree/node.rb', line 9

def tree
  @tree
end

Instance Method Details

#current_depth ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 32

def current_depth
  Math.log2(slot).floor + 1
end

#leaf? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/binary_decision_tree/node.rb', line 28

def leaf?
  left.nil? && right.nil?
end

#left ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 52

def left
  tree.at(left_position)
end

#left_position ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 40

def left_position
  slot * 2
end

#parent ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 48

def parent
  tree.at(parent_position)
end

#parent_position ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 36

def parent_position
  (slot % 2 == 0 ? slot + 1 : slot) / 2
end

#right ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 56

def right
  tree.at(right_position)
end

#right_position ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 44

def right_position
  left_position + 1
end

#value ⇒ Object 



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# File 'lib/binary_decision_tree/node.rb', line 17

def value
  case decision
    when LEFT
      left.nil? ? left_position : left.value
    when RIGHT
      right.nil? ? right_position : right.value
    else
      nil
  end
end