Komodo 12 and MCTS

[lkaufman]

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!

[shrapnel]

Very disappointing that "it doesn't utilize the GPU", especially with my brand-new Geforce 1080 Ti reaching me in a couple of days.

[Werewolf]

So Larry, is this new version using the old Komodo hand-tuned evaluation function, but with MCTS "search"?

There's no NN in the pipeline..?

[peter]

Thanks a lot, Larry!
Seems a great idea to me, already downloaded.

but for this release you just select it by UCI option.

Finding just a check- box for MCTS, numer of threads used for it has to be defined in total threads- number of the engine.

If I install a second one k12-Engine in GUI with MCTS off, I can let run both simultaneously to see the different outputs, of course, but is it planned to get shared hash for the two different kinds of search too sometimes?
Or doesn't that make sense to you?

[Damir]

I was wondering why on Komodo website it says Komodo 12 released March 5 2018.

[Ozymandias]

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)

I guess they plan to offer free upgrades, at least for this new engine? Otherwise they'll be selling an early prototype that will soon become outdated.

[Werner]

Thanks Larry for the new version. With MCTS testing I have a question about :
"Monte Carlo Tree search requires extra memory"
- I see memory raises e.g. from 256 MB till about 800 MB
- when a new game starts, usually the engine is new started and all begins again
- is there a diffence when making a tournament where the engine is not new started, will the memory raise more and the engine benefits from it?
- are these learning data in the memory?

Werner

[shrapnel]

Otherwise they'll be selling an early prototype that will soon become outdated.

Pointless having MCTS option when its unable to use the power of the GPU or of Tensor Processing Units.
Sorry, but the simple truth is that this is just a Sales Gimmick by the Komodo team trying to take advantage of the current interest in MCTS and Neural Networks.

[Joerg Oster]

Otherwise they'll be selling an early prototype that will soon become outdated.

Pointless having MCTS option when its unable to use the power of the GPU or of Tensor Processing Units.
Sorry, but the simple truth is that this is just a Sales Gimmick by the Komodo team trying to take advantage of the current interest in MCTS and Neural Networks.

Why would the MCTS benefit from using the GPU?

[shrapnel]

Why would the MCTS benefit from using the GPU?

The "Why" I wouldn't know, not being a Programmer.
What I DO know is that AlphaZero used TPUs while thrashing Stockfish and that the GPU version of LCZero is much stronger than the CPU version.