210 lines
8.3 KiB
Python
210 lines
8.3 KiB
Python
import numpy as np
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import math
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import time
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import sys
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import collections
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c_puct = 5
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def hashable_conversion(obj):
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if isinstance(obj, collections.Hashable):
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return obj
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else:
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return tuple(hashable_conversion(sub) for sub in obj)
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class MCTSNode(object):
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def __init__(self, parent, action, state, action_num, prior, inverse=False):
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self.parent = parent
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self.action = action
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self.children = {}
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self.state = state
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self.action_num = action_num
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self.prior = np.array(prior).reshape(-1)
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self.inverse = inverse
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def selection(self, simulator):
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raise NotImplementedError("Need to implement function selection")
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def backpropagation(self, action):
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raise NotImplementedError("Need to implement function backpropagation")
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def valid_mask(self, simulator):
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pass
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class UCTNode(MCTSNode):
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def __init__(self, parent, action, state, action_num, prior, mcts, inverse=False):
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super(UCTNode, self).__init__(parent, action, state, action_num, prior, inverse)
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self.Q = np.zeros([action_num])
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self.W = np.zeros([action_num])
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self.N = np.zeros([action_num])
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self.c_puct = c_puct
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self.ucb = self.Q + self.c_puct * self.prior * math.sqrt(np.sum(self.N)) / (self.N + 1)
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self.mask = None
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self.elapse_time = 0
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self.mcts = mcts
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def selection(self, simulator):
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head = time.time()
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self.valid_mask(simulator)
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self.mcts.valid_mask_time += time.time() - head
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action = np.argmax(self.ucb)
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if action in self.children.keys():
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self.mcts.state_selection_time += time.time() - head
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return self.children[action].selection(simulator)
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else:
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self.children[action] = ActionNode(self, action, mcts=self.mcts)
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self.mcts.state_selection_time += time.time() - head
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return self.children[action].selection(simulator)
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def backpropagation(self, action):
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action = int(action)
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self.N[action] += 1
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self.W[action] += self.children[action].reward
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for i in range(self.action_num):
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if self.N[i] != 0:
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self.Q[i] = (self.W[i] + 0.) / self.N[i]
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self.ucb = self.Q + c_puct * self.prior * math.sqrt(np.sum(self.N)) / (self.N + 1.)
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if self.parent is not None:
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if self.inverse:
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self.parent.backpropagation(-self.children[action].reward)
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else:
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self.parent.backpropagation(self.children[action].reward)
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def valid_mask(self, simulator):
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# let all invalid actions be illegal in mcts
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if not hasattr(simulator, 'simulate_get_mask'):
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pass
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else:
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if self.mask is None:
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self.mask = simulator.simulate_get_mask(self.state, range(self.action_num))
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self.ucb[self.mask] = -float("Inf")
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# Code reserved for Thompson Sampling
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class TSNode(MCTSNode):
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def __init__(self, parent, action, state, action_num, prior, method="Gaussian", inverse=False):
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super(TSNode, self).__init__(parent, action, state, action_num, prior, inverse)
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if method == "Beta":
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self.alpha = np.ones([action_num])
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self.beta = np.ones([action_num])
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if method == "Gaussian":
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self.mu = np.zeros([action_num])
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self.sigma = np.zeros([action_num])
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class ActionNode(object):
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def __init__(self, parent, action, mcts):
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self.parent = parent
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self.action = action
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self.children = {}
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self.next_state = None
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self.next_state_hashable = None
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self.state_type = None
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self.reward = 0
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self.mcts = mcts
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def selection(self, simulator):
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head = time.time()
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self.next_state, self.reward = simulator.simulate_step_forward(self.parent.state, self.action)
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self.mcts.simulate_sf_time += time.time() - head
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if self.next_state is None: # next_state is None means that self.parent.state is the terminate state
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self.mcts.action_selection_time += time.time() - head
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return self.parent, self.action
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self.next_state_hashable = hashable_conversion(self.next_state)
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if self.next_state_hashable in self.children.keys(): # next state has already visited before
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self.mcts.action_selection_time += time.time() - head
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return self.children[self.next_state_hashable].selection(simulator)
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else: # next state is a new state never seen before
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self.mcts.action_selection_time += time.time() - head
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return self.parent, self.action
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def expansion(self, evaluator, action_num):
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if self.next_state is not None:
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# note that self.next_state was assigned already at the selection function
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prior, value = evaluator(self.next_state)
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self.children[self.next_state_hashable] = UCTNode(self, self.action, self.next_state, action_num, prior,
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mcts=self.mcts, inverse=self.parent.inverse)
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return value
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else: # self.next_state is None means MCTS selected a terminate node
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return 0.
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def backpropagation(self, value):
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self.reward += value
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self.parent.backpropagation(self.action)
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class MCTS(object):
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def __init__(self, simulator, evaluator, start_state, action_num, method="UCT",
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role="unknown", debug=False, inverse=False):
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self.simulator = simulator
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self.evaluator = evaluator
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self.role = role
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self.debug = debug
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prior, _ = self.evaluator(start_state)
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self.action_num = action_num
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if method == "":
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self.root = start_state
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if method == "UCT":
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self.root = UCTNode(None, None, start_state, action_num, prior, mcts=self, inverse=inverse)
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if method == "TS":
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self.root = TSNode(None, None, start_state, action_num, prior, inverse=inverse)
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self.inverse = inverse
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# time spend on each step
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self.selection_time = 0
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self.expansion_time = 0
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self.backpropagation_time = 0
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self.action_selection_time = 0
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self.state_selection_time = 0
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self.simulate_sf_time = 0
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self.valid_mask_time = 0
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self.ndarray2list_time = 0
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self.list2tuple_time = 0
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self.check = 0
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def search(self, max_step=None, max_time=None):
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step = 0
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start_time = time.time()
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if max_step is None:
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max_step = int("Inf")
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if max_time is None:
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max_time = float("Inf")
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if max_step is None and max_time is None:
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raise ValueError("Need a stop criteria!")
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while step < max_step and time.time() - start_time < max_step:
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sel_time, exp_time, back_time = self._expand()
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self.selection_time += sel_time
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self.expansion_time += exp_time
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self.backpropagation_time += back_time
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step += 1
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if self.debug:
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file = open("mcts_profiling.txt", "a")
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file.write("[" + str(self.role) + "]"
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+ " sel " + '%.3f' % self.selection_time + " "
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+ " sel_sta " + '%.3f' % self.state_selection_time + " "
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+ " valid " + '%.3f' % self.valid_mask_time + " "
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+ " sel_act " + '%.3f' % self.action_selection_time + " "
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+ " array2list " + '%.4f' % self.ndarray2list_time + " "
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+ " check " + str(self.check) + " "
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+ " list2tuple " + '%.4f' % self.list2tuple_time + " \t"
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+ " forward " + '%.3f' % self.simulate_sf_time + " "
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+ " exp " + '%.3f' % self.expansion_time + " "
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+ " bak " + '%.3f' % self.backpropagation_time + " "
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+ "\n")
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file.close()
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def _expand(self):
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t0 = time.time()
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node, new_action = self.root.selection(self.simulator)
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t1 = time.time()
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value = node.children[new_action].expansion(self.evaluator, self.action_num)
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t2 = time.time()
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if self.inverse:
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node.children[new_action].backpropagation(-value + 0.)
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else:
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node.children[new_action].backpropagation(value + 0.)
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t3 = time.time()
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return t1 - t0, t2 - t1, t3 - t2
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if __name__ == "__main__":
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pass
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