【新智元导读】德扑被认为是难度远超其他游戏的人工智能挑战项目。然而CMU和Facebook联合打造的AI赌神Pluribus,训练成本150美元、8天训练时间即吊打职业选手,每小时赢1000美元!如此强悍的AI是如何炼成的?要研究其算法该如何入手?有请幕后研究人员为您解答。
人们发现规则明确的游戏,即使像星际这样战局多变的即时战略游戏,人类也无法战胜拥有碾压性算力优势的计算机。于是有人寄希望于带有运气成分、需要大量心里战的德州扑克。
德州扑克 (Texas hold'em,有时也简称为Hold'em或Holdem),简称德扑,是世界上最流行的公牌扑克衍生游戏,也是国际扑克比赛的正式竞赛项目之一。德州扑克是位置顺序影响最大的扑克衍生游戏之一,因为所有轮数的下注次序维持不变。它也是美国多数赌场内最受欢迎的扑克牌类游戏,在美国以外的地区也十分流行,理论上一桌同时最多可容纳22位(若不销牌则为23位)牌手,但一般是二至十人一桌。赌神下凡:1小时赢7000块,一周炼成百万富翁
扑克是典型的不完美信息博弈游戏。德州扑克中,玩家无法获知已发生事件的全部信息,一对一无限注中包含10^160个决策点(decision points)。
每个点需要根据出牌方的理解,产生不同的路径。这种不完整信息的特质,使得德州扑克成为难度远超其他游戏的人工智能挑战项目。
然而,其实结局早就在暗中被注定了。40年来,科学家就一直没有停止过对德州的研究。
10年前,计算机第一次在有限制的德州扑克游戏中,战胜了人类顶级选手;4年前,来自加拿大阿尔伯塔大学的研究团队开发出Cepheus(仙王座),一个号称人类无法战胜的扑克机器人;2年前,也就是2017年,加拿大和捷克的科学家在arXiv上发表论文,提出名为DeepStack的算法,称可以让人工智能在比赛中拥有“直觉”。
而前两天,在CMU科学家的努力下,人工智能已经在六人无限注德扑比赛上击败所有人类顶尖玩家。只存在于电影电视剧中的赌神,现在真实的存在于现实世界了!
https://www.nature.com/articles/d41586-019-02156-9
https://science.sciencemag.org/content/early/2019/07/10/science.aay2400
https://www.techmeme.com/
而这个赌神Pluribus的“炼成”却很像一个寒门子弟黑马突袭的故事:用来训练Pluribus的电脑1000块人民币不到,在2块CPU上实施运行。
上图显示了在64核CPU训练期间,Pluribus的蓝图策略的改进过程。绩效是根据训练的最终快照来衡量的。
正是凭着这么简陋的装备,Pluribus一小时赢了人类将近7000人民币。按照这样的速度,AI通过德州成为百万富翁,只需要不到一周的时间。
赌神是怎么炼成的?幕后科学家在线答疑显然,赌神AI引爆了大众情绪。技术人员最关心的,除了它能赢钱外,恐怕就是它背后的运作机制了。
近日,这位“AI赌神” Pluribus的幕后推手,Facebook AI Research研究科学家、CMU计算机科学博士在读Noam Brown,以及CMU教授Tuomas Sandholm,共同在Reddit发声,揭秘赌神AI幕后花絮,并回答网友提问。大伙儿热情高涨,贡献了超过130个回帖。
会对扑克网站造成影响吗?
最为全世界最受欢迎的扑克游戏之一,德州扑克在美国及世界范围内拥有大量的玩家。大家非常关心AI赌神以后,会不会在短时间内对线上德州扑克产生影响(言外之意:是否会有老千用人工智能冒充真人用户)?此外,Reddit用户DlC3R还问了另一个大家很关心的问题:算法之间的博弈何时开始?
Noam认为,现在主流扑克网站上,都有在用先进的机器人检测技术,并且已经非常成熟,用机器人出老千的风险太大,一点都不值当。但肯定会对职业扑克(例如选手、行业、俱乐部等)产生影响,起码俱乐部可以使用人工智能来训练职业扑克选手。
不过Noam还补充了一句:我们只关注人工智能而非扑克(言外之意,我们只是痴迷与技术钻研的人,其它的,也着实没有时间和精力去顾及许多啦!)
解释一下如何使用AIVAT来减少方差因子
Noam称他们估计机器人的胜率为5bb/100,也就是说,在50美元/100美元的盲注和10000美元的筹码下,如果每个筹码等值1美元,Pluribus平均每手赢得5美元的奖金,这样的话每小时可以赚到1000美元(约等于7000人民币)。
德州扑克盈利计算单位是“每百局赢利大盲注,BB/100(p值为0.021)”。优秀的职业选手能达到3-7BB/100手,显然AI的这个胜率已经非常高了!
如果没有方差减少,那么专业人士可能需要在连续4个月内,每周5天、每天8小时打牌,才能获得有价值的样本量。
感谢阿尔伯塔大学和布拉格查尔斯大学的研究人员开发了名为AIVAT的扑克方差减少算法,最终减少了约12.5倍的手数。
AIVAT可以有效的减少运气的成分,例如,如果机器人有一手牌非常强,AIVAT就会从奖金里减去一个基线值来抵消运气成分。
上面的视频中显示了蒙特卡罗CFR算法通过评估实际和假设行动值,来更新遍历者策略的过程。在Pluribus中,出于优化目的,这种遍历实际上是以深度优先的方式完成的。
研究Pluribus算法应该从何处入手?
一位名为smoke_carrot的人显然是个比较好学的人。他想要认真研究Pluribus背后的算法,但发现Pluribus所使用的方法跟他平时接触的不一样,希望研究人员能给一些指导建议,例如该从哪儿入手?该看哪方面的书籍?
Tuomas教授肯定了这位smoke_carrot的论断,确实Pluribus的算法跟强化学习、MCTS完全不同。而且,目前在解决不完美信息游戏这方面,没有很好的教材。加之这个领域发展过于迅速,以至于2010年到2015年的论文都过时了。
他建议有兴趣想进行深入研究的同学,应该去阅读本次研究的相关论文。目前最新发布的论文还是可以免费获取,这个是需要认真研读的!
随后Tuomas教授精心挑选了一些相关论文以及报告,方便大家进行学习研究:
- Keynote “New Results for Solving Imperfect-Information Games” at the Association for the Advancement of Artificial Intelligence Annual Conference (AAAI), 2019, available on Vimeo. (https://vimeo.com/313942390)
- Keynote “Super-Human AI for Strategic Reasoning: Beating Top Pros in Heads-Up No-Limit Texas Hold’em” at the International Joint Conference on Artificial Intelligence (IJCAI), available on YouTube. (https://www.youtube.com/watch?v=xrWulRY_t1o)
- Solving Imperfect-Information Games. (http://www.cs.cmu.edu/~sandholm/Solving games.Science-2015.pdf) Science 347(6218), 122-123, 2015.
- Abstraction for Solving Large Incomplete-Information Games. (http://www.cs.cmu.edu/~sandholm/game abstraction.aaai15SMT.pdf) In AAAI, Senior Member Track, 2015.
- The State of Solving Large Incomplete-Information Games, and Application to Poker. (http://www.cs.cmu.edu/~sandholm/solving games.aimag11.pdf) AI Magazine, special issue on Algorithmic Game Theory, Winter, 13-32, 2010.
- Brown, N. and Sandholm, T. 2019. Superhuman AI for multiplayer poker. (https://science.sciencemag.org/content/early/2019/07/10/science.aay2400) Science, July 11th.
- Farina, G., Kroer, C., and Sandholm, T. 2019. Regret Circuits: Composability of Regret Minimizers. In Proceedings of the International Conference on Machine Learning (ICML), 2019. arXiv version. (https://arxiv.org/abs/1811.02540)
- Farina, G., Kroer, C., Brown, N., and Sandholm, T. 2019. Stable-Predictive Optimistic Counterfactual Regret Minimization. In ICML. arXiv version. (https://arxiv.org/pdf/1902.04982.pdf)
- Brown, N, Lerer, A., Gross, S., and Sandholm, T. 2019. Deep Counterfactual Regret Minimization In ICML. Early version (https://arxiv.org/pdf/1811.00164.pdf) in NeurIPS-18 Deep RL Workshop, 2018.
- Brown, N. and Sandholm, T. 2019. Solving Imperfect-Information Games via Discounted Regret Minimization (https://arxiv.org/pdf/1809.04040.pdf). In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI). Outstanding Paper Honorable Mention, one of four papers receiving special recognition out of 1,150 accepted papers and 7,095 submissions.
- Farina, G., Kroer, C., and Sandholm, T. 2019. Online Convex Optimization for Sequential Decision Processes and Extensive-Form Games (http://www.cs.cmu.edu/~gfarina/2018/laminar-regret-aaai19/). In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI).
- Marchesi, A., Farina, G., Kroer, C., Gatti, N., and Sandholm, T. 2019. Quasi-Perfect Stackelberg Equilibrium (http://www.cs.cmu.edu/~gfarina/2018/qp-stackelberg-aaai19/). In Proceedings of the AAAI Conference on Artificial Intelligence (AAAI).
- Farina, G., Kroer, C., Brown, N., and Sandholm, T. 2019. Stable-Predictive Optimistic Counterfactual Regret Minimization (https://arxiv.org/pdf/1902.04982.pdf). arXiv.
- Brown, N. and Sandholm, T. 2018. Superhuman AI for heads-up no-limit poker: Libratus beats top professionals. (http://science.sciencemag.org/content/early/2017/12/15/science.aao1733) Science, full Research Article.
- Brown, N., Lerer, A., Gross, S., and Sandholm, T. 2018. Deep Counterfactual Regret Minimization (https://arxiv.org/pdf/1811.00164.pdf). NeurIPS Deep Reinforcement Learning Workshop. *Oral Presentation*.
- Kroer, C., Waugh, K., Kilinc-Karzan, F., and Sandholm, T. 2018. Faster algorithms for extensive-form game solving via improved smoothing functions. (https://rdcu.be/8EyP) Mathematical Programming, Series A. Abstract published in EC-17.
- Brown, N., Sandholm, T., and Amos, B. 2018. Depth-Limited Solving for Imperfect-Information Games. (https://arxiv.org/pdf/1805.08195.pdf) In Proc. Neural Information Processing Systems (NeurIPS).
- Kroer, C. and Sandholm, T. 2018. A Unified Framework for Extensive-Form Game Abstraction with Bounds. In NIPS. Early version (http://www.cs.cmu.edu/~ckroer/papers/unified_abstraction_framework_ai_cubed.pdf) in IJCAI-18 AI^3 workshop.
- Farina, G., Gatti, N., and Sandholm, T. 2018. Practical Exact Algorithm for Trembling-Hand Equilibrium Refinements in Games. (http://www.cs.cmu.edu/~gfarina/2017/trembling-lp-refinements-nips18/) In NeurIPS.
- Kroer, C., Farina, G., and Sandholm, T. 2018. Solving Large Sequential Games with the Excessive Gap Technique. (https://arxiv.org/abs/1810.03063) In NeurIPS. Also Spotlight presentation.
- Farina, G., Celli, A., Gatti, N., and Sandholm, T. 2018. Ex Ante Coordination and Collusion in Zero-Sum Multi-Player Extensive-Form Games. (http://www.cs.cmu.edu/~gfarina/2018/collusion-3players-nips18/) In NeurIPS.
- Farina, G., Marchesi, A., Kroer, C., Gatti, N., and Sandholm, T. 2018. Trembling-Hand Perfection in Extensive-Form Games with Commitment. (http://www.cs.cmu.edu/~ckroer/papers/stackelberg_perfection_ijcai18.pdf) In IJCAI.
- Kroer, C., Farina, G., and Sandholm, T*. 2018. *Robust Stackelberg Equilibria in Extensive-Form Games and Extension to Limited Lookahead. (http://www.cs.cmu.edu/~ckroer/papers/robust.aaai18.pdf) In Proc. AAAI Conference on AI (AAAI).
- Brown, N., and Sandholm, T. 2017. Safe and Nested Subgame Solving for Imperfect-Information Games. (https://www.cs.cmu.edu/~noamb/papers/17-NIPS-Safe.pdf) In NIPS. *Best Paper Award, out of 3,240 submissions.
- Farina, G., Kroer, C., Sandholm, T. 2017. Regret Minimization in Behaviorally-Constrained Zero-Sum Games. (http://www.cs.cmu.edu/~sandholm/behavioral.icml17.pdf) In Proc. International Conference on Machine Learning (ICML).
- Brown, N. and Sandholm, T. 2017. Reduced Space and Faster Convergence in Imperfect-Information Games via Pruning. (http://www.cs.cmu.edu/~sandholm/reducedSpace.icml17.pdf) In ICML.
- Kroer, C., Farina, G., Sandholm, T. 2017. Smoothing Method for Approximate Extensive-Form Perfect Equilibrium. (http://www.cs.cmu.edu/~sandholm/smoothingEFPE.ijcai17.pdf) In IJCAI. ArXiv version. (http://arxiv.org/abs/1705.09326)
- Brown, N., Kroer, C., and Sandholm, T. 2017. Dynamic Thresholding and Pruning for Regret Minimization. (http://www.cs.cmu.edu/~sandholm/dynamicThresholding.aaai17.pdf) In AAAI.
- Kroer, C. and Sandholm, T. 2016. Imperfect-Recall Abstractions with Bounds in Games. (http://www.cs.cmu.edu/~sandholm/imperfect-recall-abstraction-with-bounds.ec16.pdf) In Proc. ACM Conference on Economics and Computation (EC).
- Noam Brown and Tuomas Sandholm. 2016. Strategy-Based Warm Starting for Regret Minimization in Games. In AAAI. Extended version with appendix. (http://www.cs.cmu.edu/~sandholm/warmStart.aaai16.withAppendixAndTypoFix.pdf)
- Noam Brown and Tuomas Sandholm. 2015. Regret-Based Pruning in Extensive-Form Games. (http://www.cs.cmu.edu/~sandholm/cs15-892F15) In NIPS. Extended version. (http://www.cs.cmu.edu/~sandholm/regret-basedPruning.nips15.withAppendix.pdf)
- Brown, N. and Sandholm, T. 2015. Simultaneous Abstraction and Equilibrium Finding in Games. (http://www.cs.cmu.edu/~sandholm/simultaneous.ijcai15.pdf) In IJCAI.
- Kroer, C. & Sandholm, T. 2015. Limited Lookahead in Imperfect-Information Games. (http://www.cs.cmu.edu/~sandholm/limited-look-ahead.ijcai15.pdf) IJCAI.
- Kroer, C., Waugh, K., Kilinc-Karzan, F., and Sandholm, T. 2015. Faster First-Order Methods for Extensive-Form Game Solving. (http://www.cs.cmu.edu/~sandholm/faster.ec15.pdf) In EC.
- Brown, N., Ganzfried, S., and Sandholm, T. 2015. Hierarchical Abstraction, Distributed Equilibrium Computation, and Post-Processing, with Application to a Champion No-Limit Texas Hold’em Agent. (http://www.cs.cmu.edu/~sandholm/hierarchical.aamas15.pdf) In Proc. Internat. Conference on Autonomous Agents and Multiagent Systems (AAMAS).
- Kroer, C. and Sandholm, T. 2015. Discretization of Continuous Action Spaces in Extensive-Form Games. (http://www.cs.cmu.edu/~sandholm/discretization.aamas15.fromACM.pdf) In AAMAS.
- Ganzfried, S. and Sandholm, T. 2015. Endgame Solving in Large Imperfect-Information Games. (http://www.cs.cmu.edu/~sandholm/endgame.aamas15.fromACM.pdf) In AAMAS.
- Kroer, C. and Sandholm, T. 2014. Extensive-Form Game Abstraction With Bounds. (http://www.cs.cmu.edu/~sandholm/extensiveGameAbstraction.ec14.pdf) In EC.
- Brown, N. and Sandholm, T. 2014. Regret Transfer and Parameter Optimization. (http://www.cs.cmu.edu/~sandholm/regret_transfer.aaai14.pdf) In AAAI.
- Ganzfried, S. and Sandholm, T. 2014. Potential-Aware Imperfect-Recall Abstraction with Earth Mover’s Distance in Imperfect-Information Games. (http://www.cs.cmu.edu/~sandholm/potential-aware_imperfect-recall.aaai14.pdf) In AAAI.
- Ganzfried, S. and Sandholm, T. 2013. Action Translation in Extensive-Form Games with Large Action Spaces: Axioms, Paradoxes, and the Pseudo-Harmonic Mapping. (http://www.cs.cmu.edu/~sandholm/reverse mapping.ijcai13.pdf) In IJCAI.
- Sandholm, T. and Singh, S. 2012. Lossy Stochastic Game Abstraction with Bounds. (http://www.cs.cmu.edu/~sandholm/lossyStochasticGameAbstractionWBounds.ec12.pdf) In EC.
- Gilpin, A., Peña, J., and Sandholm, T. 2012. First-Order Algorithm with O(ln(1/epsilon)) Convergence for epsilon-Equilibrium in Two-Person Zero-Sum Games. (http://www.cs.cmu.edu/~sandholm/restart.MathProg12.pdf) Mathematical Programming 133(1-2), 279-298. Subsumes our AAAI-08 paper.
- Ganzfried, S., Sandholm, T., and Waugh, K. 2012. Strategy Purification and Thresholding: Effective Non-Equilibrium Approaches for Playing Large Games. (http://www.cs.cmu.edu/~sandholm/StrategyPurification_AAMAS2012_camera_ready_2.pdf) In AAMAS.
- Ganzfried, S. and Sandholm, T. 2012. Tartanian5: A Heads-Up No-Limit Texas Hold'em Poker-Playing Program. (http://www.cs.cmu.edu/~sandholm/Tartanian_ACPC12_CR.pdf) Computer Poker Symposium at AAAI.
- Hoda, S., Gilpin, A., Peña, J., and Sandholm, T. 2010. Smoothing techniques for computing Nash equilibria of sequential games. (http://www.cs.cmu.edu/~sandholm/proxtreeplex.MathOfOR.pdf) Mathematics of Operations Research 35(2), 494-512.
- Ganzfried, S. and Sandholm, T. 2010 Computing Equilibria by Incorporating Qualitative Models (http://www.cs.cmu.edu/~sandholm/qualitative.aamas10.pdf). In AAMAS. Extended version (http://www.cs.cmu.edu/~sandholm/qualitative.TR10.pdf): CMU technical report CMU-CS-10-105.
- Gilpin, A. and Sandholm, T. 2010. Speeding Up Gradient-Based Algorithms for Sequential Games (Extended Abstract) (http://www.cs.cmu.edu/~sandholm/speedup.aamas10.pdf). In AAMAS.
- Ganzfried, S. and Sandholm, T. 2009. Computing Equilibria in Multiplayer Stochastic Games of Imperfect Information (http://www.cs.cmu.edu/~sandholm/stochgames.ijcai09.pdf). In IJCAI.
他还补充了2008年以及之前关于不完全信息游戏的计算解决的精选论文:
- Gilpin, A. and Sandholm, T. 2008. Expectation-Based Versus Potential-Aware Automated Abstraction in Imperfect Information Games: An Experimental Comparison Using Poker. (http://www.cs.cmu.edu/~sandholm/expectation-basedVsPotential-Aware.AAAI08.pdf) In AAAI.
- Ganzfried, S. and Sandholm, T. 2008. Computing an Approximate Jam/Fold Equilibrium for 3-Agent No-Limit Texas Hold'em Tournaments. (http://www.cs.cmu.edu/~sandholm/3-player jam-fold.AAMAS08.pdf) In AAMAS.
- Gilpin, A., Sandholm, T., and Sørensen, T. 2008. A heads-up no-limit Texas Hold'em poker player: Discretized betting models and automatically generated equilibrium-finding programs. (http://www.cs.cmu.edu/~sandholm/tartanian.AAMAS08.pdf) In AAMAS.
- Gilpin, A. and Sandholm, T. 2007. Lossless abstraction of imperfect information games (http://www.cs.cmu.edu/~sandholm/extensive.jacm07.pdf). Journal of the ACM, 54 (5). Early versions in EC-06.
- Gilpin, A., Sandholm, T., and Sørensen, T. 2007. Potential-Aware Automated Abstraction of Sequential Games, and Holistic Equilibrium Analysis of Texas Hold'em Poker. (http://www.cs.cmu.edu/~sandholm/gs3.aaai07.pdf) In AAAI.
- Gilpin, A. and Sandholm, T. 2007. Better automated abstraction techniques for imperfect information games, with application to Texas Hold'em poker. (http://www.cs.cmu.edu/~sandholm/gs2.aamas07.pdf) In AAMAS.
- Gilpin, A. and Sandholm, T. 2006. A competitive Texas Hold'em Poker player via automated abstraction and real-time equilibrium computation. (http://www.cs.cmu.edu/~sandholm/texas.aaai06.pdf) In AAAI.
如果你对此感兴趣,希望看到更多讨论,请移步Reddit:
https://www.reddit.com/r/MachineLearning/comments/ceece3/ama_we_are_noam_brown_and_tuomas_sandholm/