I see the same dynamics that you do, Darren. The 400-game match always has some probability of being won by the challenger. It is just much more likely if the challenger is stronger than the champion.
-----Original Message----- From: Computer-go [mailto:computer-go-boun...@computer-go.org] On Behalf Of Darren Cook Sent: Wednesday, December 6, 2017 7:55 PM To: computer-go@computer-go.org Subject: Re: [Computer-go] Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm >> One of the changes they made (bottom of p.3) was to continuously >> update the neural net, rather than require a new network to beat it >> 55% of the time to be used. (That struck me as strange at the time, >> when reading the AlphaGoZero paper - why not just >50%?) Gian wrote: > I read that as a simple way of establishing confidence that the result > was statistically significant > 0. (+35 Elo over 400 games... Brian Sheppard also: > Requiring a margin > 55% is a defense against a random result. A 55% > score in a 400-game match is 2 sigma. Good point. That makes sense. But (where A is best so far, and B is the newer network) in A vs. B, if B wins 50.1%, there is a slightly greater than 50-50 chance that B is better than A. In the extreme case of 54.9% win rate there is something like a 94%-6% chance (?) that B is better, but they still throw B away. If B just got lucky, and A was better, well the next generation is just more likely to de-throne B, so long-term you won't lose much. On the other hand, at very strong levels, this might prevent improvement, as a jump to 55% win rate in just one generation sounds unlikely to happen. (Did I understand that right? As B is thrown away, and A continues to be used, there is only that one generation within which to improve on it, each time?) Darren _______________________________________________ Computer-go mailing list Computer-go@computer-go.org http://computer-go.org/mailman/listinfo/computer-go _______________________________________________ Computer-go mailing list Computer-go@computer-go.org http://computer-go.org/mailman/listinfo/computer-go
