05_CartPole-reinforcement-learning_PER_D3QN

SumTree_get_leaf.py

def get_leaf(self, v):
    parent_index = 0

    while True:
        left_child_index = 2 * parent_index + 1
        right_child_index = left_child_index + 1

        # If we reach bottom, end the search
        if left_child_index >= len(self.tree):
            leaf_index = parent_index
            break
        else: # downward search, always search for a higher priority node
            if v <= self.tree[left_child_index]:
                parent_index = left_child_index
            else:
                v -= self.tree[left_child_index]
                parent_index = right_child_index

    data_index = leaf_index - self.capacity + 1

    return leaf_index, self.tree[leaf_index], self.data[data_index]

    @property
    def total_priority(self):
        return self.tree[0] # Returns the root node