Thore Graepel Google Deep Mind, London
AlphaGo: Mastering the game of Go with deep neural networks and tree search
The game of Go has long been viewed as the most challenging of classic games for artificial intelligence owing to its enormous search space and the difficulty of evaluating board positions and moves. Here we introduce a new approach to computer Go that uses ‘value networks’ to evaluate board positions and ‘policy networks’ to select moves. These deep neural networks are trained by a novel combination of supervised learning from human expert games, and reinforcement learning from games of self-play. Without any lookahead search, the neural networks play Go at the level of state-of-the-art Monte Carlo tree search programs that simulate thousands of random games of self-play. We also introduce a new search algorithm that combines Monte Carlo simulation with value and policy networks. Using this search algorithm, our program AlphaGo achieved a 99.8% winning rate against other Go programs, and defeated the human European Go champion by 5 games to 0. This is the first time that a computer program has defeated a human professional player in the full-sized game of Go, a feat previously thought to be at least a decade away.
The talk is based on a recent Nature article about work carried out at Google Deepmind in collaboration with David Silver, Aja Huang, Chris J. Maddison, Arthur Guez, Laurent Sifre, George van den Driessche, Julian Schrittwieser, Ioannis Antonoglou, Veda Panneershelvam, Marc Lanctot, Sander Dieleman, Dominik Grewe, John Nham, Nal Kalchbrenner, Ilya Sutskever, Timothy Lillicrap, Madeleine Leach, Koray Kavukcuoglu, and Demis Hassabis.
Thore Graepel is an allround machine learning researcher with experience across statistical learning theory, kernel methods, optimization, Bayesian inference, graphical models, crowdsourcing and reinforcement learning. Before joining DeepMind, Thore spent twelve years at Microsoft Research developing machine learning algorithms at web scale including TrueSkill for player ranking in Xbox Live, AdPredictor for click-through rate prediction in Bing, and Matchbox for movie recommendations on Xbox Live marketplace. On the academic side, Thore is affiliated with the Computer Science Department of University College London as professor of machine learning. At DeepMind, Thore is returning to his original dream of helping to understand intelligence and build intelligent agents.