Komodo 12 and MCTS
Posted: Mon May 14, 2018 8:11 am
We have just released Komodo 12 this morning at komodochess.com. While the strength of the normal version is only up about five elo from Komodo 11.3.1 (roughly forty elo at blitz levels from Komodo 11), that is because we have spent the last month creating a Komodo MCTS (Monte-Carlo Tree Search) option for it. It is really a second engine, and I understand that ChessBase will treat it as an independent engine when they release their version of Komodo 12 (soon), but for this release you just select it by UCI option. It is by no means as strong as normal Komodo, but we are reasonably certain that it is the strongest MCTS engine available at this time for the pc. We estimate that its rating on the CCRL 40/40 scale will be about 3000 on one thread, 3050 on two, and 3070 on three or more. Currently it is not able to benefit from running on more than three threads, but we expect to raise or eliminate this limit in the next month or so and if so we will offer one update (together with other improvements to the MCTS version) free to all purchasers of Komodo 12. Of course subscribers get free updates for a full year. We intend to focus on the MCTS version for at least the next month or two, because it is still improving rapidly while progress has slowed with normal Komodo. Potential subscribers can expect more frequent updates than in the past year, but the updates may be primarily of benefit to MCTS users. Unlike "Leela", it does not need or utilize a GPU. Note also that for people with quadcore computers, the three thread limit is not much of a disadvantage, as many users prefer to keep one thread free for the GUI, the operating system, the internet etc.
There are several advantages to the MCTS option.
1. Multi-PV display does not weaken Komodo MCTS in contrast to normal Komodo. In fact, tests indicate that with all legal moves displayed by both versions, the elo gap disappears (within margin of error).
2. Although tactical strength is lower with MCTS, positional play and judgment may well be better in many positions. Judging between good and bad gambits seems to be better with MCTS, although that is just my subjective opinion.
3. Evals don't fluctuate so suddenly or wildly.
4. Eventually it should be able to benefit from many cores more than normal Komodo, although that is obviously not true yet.
5. It will be much easier to improve. It is still in its infancy, and practically everything it does has yet to be tuned. It is also possible that fairly radical changes will prove to be very beneficial, as we have only tried a couple approaches so far.
I have no idea whether Komoco MCTS can catch or surpass normal Komodo, but we intend to try!
There are several advantages to the MCTS option.
1. Multi-PV display does not weaken Komodo MCTS in contrast to normal Komodo. In fact, tests indicate that with all legal moves displayed by both versions, the elo gap disappears (within margin of error).
2. Although tactical strength is lower with MCTS, positional play and judgment may well be better in many positions. Judging between good and bad gambits seems to be better with MCTS, although that is just my subjective opinion.
3. Evals don't fluctuate so suddenly or wildly.
4. Eventually it should be able to benefit from many cores more than normal Komodo, although that is obviously not true yet.
5. It will be much easier to improve. It is still in its infancy, and practically everything it does has yet to be tuned. It is also possible that fairly radical changes will prove to be very beneficial, as we have only tried a couple approaches so far.
I have no idea whether Komoco MCTS can catch or surpass normal Komodo, but we intend to try!
