Class: MCTS::Root

Inherits:
Node
  • Object
show all
Defined in:
lib/mcts/root.rb

Instance Attribute Summary

Attributes inherited from Node

#children, #game_state, #move, #parent, #visits, #wins

Instance Method Summary collapse

Methods inherited from Node

#backpropagate, #expand, #leaf?, #lost, #rollout, #uct_select_child, #uct_value, #untried_moves?, #win_percentage, #won

Constructor Details

#initialize(game_state) ⇒ Root

Returns a new instance of Root.



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# File 'lib/mcts/root.rb', line 3

def initialize(game_state)
  super game_state, nil, nil
end

Instance Method Details

#best_child ⇒ Object 



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# File 'lib/mcts/root.rb', line 11

def best_child
  children.max_by &:win_percentage
end

#best_move ⇒ Object 



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# File 'lib/mcts/root.rb', line 15

def best_move
  best_child.move
end

#explore_tree ⇒ Object 



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# File 'lib/mcts/root.rb', line 19

def explore_tree
  selected_node = select
  playout_node =  if selected_node.leaf?
                    selected_node
                  else
                    selected_node.expand
                  end
  won = playout_node.rollout
  playout_node.backpropagate(won)
end

#root? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mcts/root.rb', line 7

def root?
  true
end

#update_won(won) ⇒ Object 



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# File 'lib/mcts/root.rb', line 30

def update_won(won)
  # logic reversed as the node accumulates its children and has no move
  # of its own
  if won
    self.lost
  else
    self.won
  end
end