Class: NeuroGammon::Board

Inherits:
Object
  • Object
show all
Defined in:
lib/neuro_gammon/board.rb

Constant Summary collapse

BLACK = 
-1
WHITE = 
1

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Board

Returns a new instance of Board.



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# File 'lib/neuro_gammon/board.rb', line 22

def initialize
  @board_state=[-2,0,0,0,0,5,0,3,0,0,0,-5,5,0,0,0,-3,0,-5,0,0,0,0,2]
  @bar=[0,0]
end

Instance Method Details

#bar_count(colour) ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 31

def bar_count colour
  return colour==Board::BLACK ? bar_state[0] : bar_state[1]
end

#bearing_off?(colour) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/neuro_gammon/board.rb', line 110

def bearing_off? colour
  return false if bar_count(colour)!=0
  range=Board::BLACK==colour ? (18..23) : (0..5)
   (0..23).each do |i|
    if not range.include?(i)
      return false if board_state[i]*colour>0
    end
  end
  return true
end

#move(move, colour) ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 75

def move move,colour
  old_state=Marshal.load(Marshal.dump(board_state))
  old_bar=Marshal.load(Marshal.dump(@bar))
  move!(move,colour)
  result=state
  @board_state=old_state
  @bar=old_bar
  return result
end

#move!(move, colour, dice = nil) ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 85

def move! move,colour,dice=nil
  validate_move move,colour
  start=move[0]
  fin=move[1]
  if start==-1
    Board::BLACK==colour ? @bar[0]-=1 : @bar[1]-=1
  elsif fin==-1
    @board_state[start]-=colour
  else
    @board_state[start]-=colour
  end
  
  if fin!=-1
    @board_state[fin]+=colour
    if (board_state[fin]==0)
      @board_state[fin]+=colour
      Board::BLACK==colour ? @bar[1]+=1 : @bar[0]+=1
    end
  end
  
  if !dice.nil?
    update_dice(dice, move)
  end
end

#piece_count(colour) ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 35

def piece_count colour
  result=0
  board_state.each do |x|
    result+=x.abs if (x/colour > 0)
  end
  result+=bar_count(colour)
  return result;
end

#state ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 27

def state
  [@board_state,@bar]
end

#valid_moves(colour, dice) ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 121

def valid_moves colour,dice
  result=[]
  if (bar_count(colour)>0)
    dice.to_a.uniq.each do |d|
      dest=colour==Board::BLACK ? d-1 : 24-d
      if board_state[dest]*colour >= -1 and board_state[dest]*colour < 5
        result << [-1,dest]
      end
    end
  else
    dice.to_a.uniq.each do |d|
      occupied_spaces(colour).each do |x|
        dest=x+d*-colour
        if ((0..23).include?(dest))
          if board_state[dest]*colour >= -1 and board_state[dest]*colour < 5
            result << [x,dest]
          end
        end
      end
      if (bearing_off?(colour))
        bearing_off_range=colour==Board::BLACK ? (18..23).to_a : (0..5).to_a.reverse
        bearing_off_range.each do |x|
          dest=x+d*-colour
          if board_state[x]*colour>0
            if (!bearing_off_range.include?(dest))
              if board_state[x]*colour>0
                result << [x,-1]
                break
              end
            else
              break
            end
          end
        end
      end
    end
  end
  return result
end

#validate_move(move, colour) ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 44

def validate_move move,colour
  valid_range=colour==WHITE ? (18..23) : (0..5)
  start=move[0]
  fin=move[1]
  
  if (move[0]==-1)
    raise Execption.new("No piece on the bar") if (bar_count(colour)==0)
    raise Exception.new("Invalid destination") if !valid_range.include?(fin)
    raise Exception.new("Wrong colour at destination") if board_state[fin]*colour < -1
  elsif (move[1]==-1)
    validate_bearing_off_move(move,colour)
  else
    raise Exception.new("Unable to move while there is a piece on the bar") if bar_count(colour)>0
    raise Exception.new("Wrong colour at destination") if board_state[fin]*colour < -1
    raise Exception.new("Move must specify start and end") if move.size!=2
    raise Exception.new("Invalid start position") if not (0..23).to_a.include?(start)
    raise Exception.new("Invalid destination position") if not (0..23).to_a.include?(fin)
    
    if (colour==Board::WHITE)
      raise Exception.new("Wrong direction for WHITE") if start<=fin
    else
      raise Exception.new("Wrong direction for BLACK") if start>=fin
    end
    raise Exception.new("Wrong colour at starting point") if board_state[start]/colour < 0
    raise Exception.new("No piece at starting point") if board_state[start]==0
    raise Exception.new("Destination is already full") if board_state[fin].abs >= 5
  end
  
  
end

#winner ⇒ Object 



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# File 'lib/neuro_gammon/board.rb', line 161

def winner
  return Board::WHITE if piece_count(Board::WHITE)==0
  return Board::BLACK if piece_count(Board::BLACK)==0
  return nil
end