Doudizhu-MCTS

en

About this repo:

• This is my course project for Programming Practice at PKU.
• The project is completed in teams, but members of my team decided to each pursue a different approach, and in this repo is my approach - which is based on MCTS.

About the algorithm:

• This is an AI for the Chinese card game Doudizhu.
• At its highest (Nov 2021), it ranked #3 on Botzone among all programs, and #1 among non-RL programs. Its ranking had fallen since then though.
  • Its name on the platform is "组合爆炸" (Combinatorial Explosion).
  • An experimental version of it is named "H_V2" on the platform.
• The algorithm is based on MCTS with Determinization, with several significant enhancements, including:
  • Assigning priors to the value of MCTS states, based on heuristics.
  • Carrying out bayesian inference on the cards of opponents, based on the cards they already played.
• The hyperparameters are tuned using an evolutionary algorithm, with multiprocessing. (see /tuning)
• The source code can be found at /source/main.cpp.

Detailed explanation will be added in the future. Well, probably.

zh

关于这个仓库：

• 这是在北京大学《程序设计实习》课程的组队大作业中，我所负责设计和实现的内容（即基于 MCTS 的思路）。
  • 该作业于 2021 上半年完成，但因为拖延症所以直到 2021/11 才上传到 GitHub 。

关于内容：

• 这是一个 叫分斗地主 游戏的 AI 。
• 截止 2021/11 ，其在 Botzone 平台上的最高 排名 是所有选手中的 #3 、非 RL 算法中的 #1 。不过之后有所下降。
  • 在平台上的 bot 名称为“组合爆炸”，代表着我将在组合数学课中挂科。
  • 平台上名为 “H_V2” 的 bot 是它的另一个版本，基于同样的代码和不同的参数。
• 基于 MCTS with Determinization 实现，并在原算法基础上进行多处改进（源码见 /source/main.cpp ），包括：
  • 用启发式函数给 MCTS 加入先验估值；
  • 根据对手的出牌，来对其手牌进行贝叶斯推断。
• 算法中有大量超参数，采用演化算法进行调参（需要多进程加速，详见 /tuning ）。

暂时没有详细的介绍，不过之后可(da)能(gai)会(hui)有(gu)。