On Wed, 2008-12-31 at 12:25 +0000, p...@tabor.com wrote: > I think Heikki makes a valid point here. I am not a particularly > strong player (about 1-2 dan european), but I have learned that > playing defensively is generally detrimental to the final result, > whereas taking the initiative is more likely to lead to a win.
This is how I feel about playing in general, but it's better stated by what a chess master once told me: "Play your own game." From his own experience he told me that weaker players often get intimidated when they play a master and play worse than they normally would. Also they avoid tactics even when that is the strongest part of their game feeling that they will surely get crushed. So the advice is to just do what you do best, play your strengths. > If moves close to the existing position are given much greater weight > than those further away, this may result in more defensive play than > otherwise. As I said before, for a weak bot this is not really a matter of playing inferior to what it is capable of. We are talking about a random strategy and playing moves that are much more likely to be good than random moves is probably not a defensive losing strategy in my opinion. I don't have a strong opinion on how good the actual strategy 3-4-5 strategy is however, I'm not much of a go player. How often is this rule violated in top level games? And when it is, can it be shown that no reasonable conforming rule exists? I don't know the answer to that. > > During much of the game, most moves between human players, even at > professional level, are played near to the previous move. So > considering all moves near to the last played move is likely to > increase the probablility of selecting the best move. This could be > the factor that is currently resulting in more wins where the 3-4-5 > rule is applied. The issue is whether resulting in more wins is correlated to playing stronger in the general case against a variety of opponents. So if one bot is NOT using this strategy and the other IS using this strategy, then one of them is not biased in this regard, yet it is losing. The conclusion I would draw here is that with high probability the one using the strategy is actually playing a better overall game. This is the simplest and most "Occam's razor" conclusion. If the bot was far stronger and much more sophisticated, then this is a rule which might very well hold it back. > > However, there are times when the best move is most definitely not in > the vicinity of the previous one, and a strong player will 'tenuki' - > i.e. leave that part of the position to play something more important > elsewhere - an urgent invasion on the other side of the board for > example. If computer go programmes are to become truly strong they > will need to have a way to emulate this kind of approach. I don't think that is in question. What is being called into question is whether there should be any kind of rules or evaluation that might occasionally be in error. The answer is crystal clear, all strong go programs have biased playouts and it works. > > In my (limited) opinion, the 3-4-5 rule may result in a short-term > gain, but will require refinement in due course to allow for what > human players might call creativity. I agree. To me this is like a chess evaluation function, nobody has every written a good one but they work really well anyway. You could do without one and watch your program get really weak. Random playouts by themselves probably never will advance beyond horrible play and thus approximate rules can be a big win. - Don > > Paul > > > > Dec 30, 2008 11:56:58 PM, computer-go@computer-go.org wrote: > > > On Wed, Dec 31, 2008 at 12:25:10AM +0100, Rémi Coulom wrote: > > > > If you'd like to try a simple pruning scheme that improves > playing > > strength on 19x19, then I'd suggest progressive widening. It > only works > > in the tree, not in the playouts. You don't need complex > patterns for > > progressive widening to work. You can simply use distance to > the > > previous move. Search moves at distance 1 from the previous > move for N > > playouts. Then add moves at distance 2 for N*x playouts. > Moves at > > distance 3 for N*x*x. > > > So, you'd be playing like a beginner, with a local answer to > every move the > opponent makes. Never taking sente to play elsewhere. Sounds > like a receipe > for a disaster to me. But then again, I am only a kyu-level > player, so I may > be wrong... > > -H > > -- > Heikki Levanto "In Murphy We Turst" heikki (at) lsd > (dot) dk > > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
