I suspect the answer is in your use of 3-ply for cube decisions. It may be called "grandmaster" but in 90% of the rollouts I have done 2-ply is closer to the result of the rollout. In some positions 3-ply is better, but I've also seen several positions that it thinks are too good to double that roll out as no double/take. If you are doubling too early and dropping too easily you won't be seeing most of your cube errors because those are the mistakes that 3-ply cube analysis makes too. I would strongly recommend any even play cube analysis over it.
Adi Kadmon wrote: > > Dear Developers > > > > I have Version GNU Backgammon 0.90-mingw 20090403, and I’ve been training > a > lot with it and finding it very strong. > > > > However, lately I’ve been encountering a phenomenon for which I cannot > account. Analyzing the money-games (a single game each time) with some of > my > opponents using the feature “Analysis” (set to “supremo” 2-ply for checker > play and to “grandmaster” 3-ply for cube decisions), I found consistently > for some of the opponents that I was significantly better than they were > by > the analysis` measures, and nevertheless I consistently lost to them more > than gain, sometimes in a ratio approaching 2:1 or 3:2! > > > > For instance, Analyzing 69(!) games with a certain opponent, with the > above > settings for the analysis function, I found the following: > > > > In 41 games I had an error rate mEMG per move (total: checker play + cube > decisions) lower than his. The advantage was his only in 27, and in 1 game > we came out equals. > > > > In 43 games I had an error rate mEMG per move (checker play) lower than > his, > whereas he had the advantage in 26 games only. > > > > In 29 games I had an error rate mEMG per cube decision lower than his, > whereas he had the advantage in 21 only, and in 19 games we came out > equals. > > > > Seeing all this, it was all the more disconcerting to find that on average > I > lost 0.2826 points per game during these 69 games! > > > > Note: the “marks” (“world-class…… awful”) for me and for him were > consistent > with the above analysis measures. The bot found my opponent to be luckier > than me on average (unfortunately I didn’t keep the exact numbers of games > on his side or mine) – but, for heaven’s sake, such luck through 69 > game!!! > With such an ostensible advantage on my side? It’s highly improbable. And > this opponent is, as I said, not the only example. > > > > I’ve been trying to imagine an explanation for these facts, such as: > > > > (1) That opponents, and a few more, happened to be definitely stronger > than gnubg. But stronger than “supremo” and “grandmaster” in such a > decided > and consistent fashion – is it conceivable? > > (2) Those opponents somehow cheated heavily on the dice (on Play65 site) > – > but I deem it very unlikely, and I’m not used to being paranoid at all… > > (3) My opponents’ style was different from gnubg’s, to which I’m much > more > accustomed (and from which I indeed learned much), even though > theoretically > their moves are a bit inferior by its standards – and one has to “know how > to win against their style” in order to succeed against them. But is such > a > thing likely? I would have rather thought that if by a very strong bot’s > standards my moves are superior on average, it’s not a relativistic but a > definite superiority and should beat a “different style”. > > (4) My errors occur in such early (or late) stages in the game in > comparison with the opponent’s errors, that my errors are “more costly”, > more decisive for the final result. However, I doubt this too: Wouldn’t > the > bot than have found my mistakes statistically very grave for the relevant > positions, thereby affecting the above measures accordingly so that on > average they again should turn out inferior, not superior?! > > > > > > Well, I trust your vast knowledge and experience would yield a suitable > explanation, or at least point to some possible explanations. > > > > Please do help! > > > > Sincerely, > > > > Adi > > _______________________________________________ > Bug-gnubg mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/bug-gnubg > > -- View this message in context: http://www.nabble.com/Is-gnubg%27s-game-analyisis-function-always-reliable--tp23233807p23391894.html Sent from the Gnu - Backgammon mailing list archive at Nabble.com. _______________________________________________ Bug-gnubg mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-gnubg
