Hey! This is Mike Johanson, one of the authors on the paper. We're swamped right now keeping the website up, talking to the press, and running Twitter, so I only have a few seconds to spare, but I'll stop by 2+2 later to answer questions.
We're on twitter as
@PolarisPoker . Check out my 30-tweet blitz from earlier today for a summary of what we've done.
We've been working towards this result for years, and have gotten closer and closer over time. Last year, we were down to 26 milli-big-blinds per game, or 1.3 BB/100, of exploitability: that's the most that a perfect counter-strategy / nemesis could win against our program. I've talked about that result on 2+2 a few times in the past, and the tools that we use to calculate that exploitability figure.
In October 2013, after I commented a few times in one 2+2 thread, our coauthor Oskari Tammelin got ahold of me. We'd worked with Oskari before, when he invented his PureCFR algorithm. He told us about two things he'd recently invented: CFR+, a new game solving algorithm based on our CFR algorithm that learns *incredibly* fast compared to what was then the state-of-the-art version of CFR, and a new compression technique that reduced the memory cost for solving holdem from 523 TB to 11 TB.
Oskari's two developments were hugely important, and opened the door to finally make solving HULHE possible. This paper is a joint effort between the U of A (me, Mike Bowling, Neil Burch) and Oskari Tammelin. It took us most of a year to write the code and tune it to be able to get the quality of result we wanted, at a memory limit that fit on our cluster, and at a CPU cost that was feasible. This was a tricky 3-way optimization. Actually running the computation used 4800 CPUs for about 70 days, with a total computation time of just under 1000 CPU-years.
The result is that our new program Cepheus is beatable for less than 1 milli-big-blind, or 0.05 BB/100. Even if you knew the perfect counter-strategy and could play it flawlessly, it'd take 60 million games to overcome the variance due to luck in order to actually have 95% confidence that you were winning. It's essentially solved: not quite perfect, but closer than any human could distinguish within a lifetime of play.
Our website is constantly going up and down right now due to traffic, but here's a link:
http://poker.srv.ualberta.ca . The site will show you the preflop strategy (as a nice set of graphics), the strategy for any decision point in the game, and will also let you play against Cepheus. Although the "Play vs Cepheus" part is the part that is most swamped at the moment. It should get easier to get through in a few days.
I'll check back in on this thread tomorrow, when we're less hectic. If you have any questions about the result, I'll be happy to answer them then.