ADD file via upload

node.py

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+import numpy as np
+import math
+import copy
+import random
+
+class MCTSNode:
+    def __init__(self, parent, prior_p):
+        self.parent = parent
+        self.children = dict()  # action -> MCTSNode
+        self.N = 0              # 访问次数
+        self.W = 0.0            # 总价值
+        self.Q = 0.0            # 平均价值
+        self.P = prior_p        # 先验概率
+
+    def expand(self, action_priors):
+        for action, prob in action_priors:
+            if action not in self.children:
+                self.children[action] = MCTSNode(self, prob)
+
+    def select(self, c_puct):
+        return max(self.children.items(),
+                   key=lambda act_node: act_node[1].Q + c_puct * act_node[1].P * math.sqrt(self.N) / (1 + act_node[1].N))
+
+    def update(self, leaf_value):
+        self.N += 1
+        self.W += leaf_value
+        self.Q = self.W / self.N
+
+    def update_recursive(self, leaf_value):
+        if self.parent:
+            self.parent.update_recursive(-leaf_value)
+        self.update(leaf_value)
+
+    def is_leaf(self):
+        return self.children == {}
+
+    def is_root(self):
+        return self.parent is None