def UCT(rootstate, maxiters, verbose=False):
root = Node(board=rootstate)
for i in range(maxiters):
node = root
board = rootstate.copy()
# selection - select best child if parent fully expanded and not terminal
while node.untried_actions == [] and node.children != []:
node = node.select()
board.move(node.action)
# expansion - expand parent to a random untried action
if node.untried_actions != [] and not board.result():
a = random.choice(node.untried_actions)
board.move(a)
node = node.expand(a, board.copy())
while board.get_moves() != [] and not board.result():
board.move(random.choice(board.get_moves()))
# backpropagation
while node != None:
result = board.result()
if result:
if node.board.player == board.player:
result = 1
else:
result = -1
else:
result = 0
node.update(result)
node = node.parent
# Output some information about the tree - can be omitted
if (verbose): print(root.TreeToString(0))
else: print(root.ChildrenToString())
s = sorted(root.children, key=lambda c: c.wins / c.visits)
return {"action": s[-1].action, "children": root.get_children()}
def UTC(root_state, itermax, verbose=False):
rootnode = Node(state=root_state)
for i in range(itermax):
node = rootnode
state = root_state.Clone()
# basicly while node is fully expanded
while node.untried_moves == [] and node.childNodes != []:
# Select
node = node.UTCSelectChild()
state.DoMove(node.move)
# Expand
if node.untried_moves != []:
m = random.choice(node.untried_moves)
state.DoMove(m)
node = node.AddChild(m, state)
# Rollout
while state.GetMoves() != []:
# so its while state is non-terminal
state.DoMove(random.choice(state.GetMoves()))
#Backprop
while node != None:
#backprop from the expanded node and work it back into the root
node.Update(state.GetResult(node.player_moved))
node = node.parentNode
if (verbose):
print(rootnode.TreeToString(0))
else:
print(rootnode.ChildrenToString())
print(rootnode.childNodes)
return sorted(rootnode.childNodes, key=lambda c: c.visits)[-1].move
