Author: Uri Blass
Date: 07:31:04 09/27/01
Go up one level in this thread
On September 27, 2001 at 09:39:22, Robert Hyatt wrote: >On September 27, 2001 at 03:59:57, Uri Blass wrote: > >>On September 26, 2001 at 21:45:46, Robert Hyatt wrote: >> >><snipped> >>>Here is the problem.. I had to explain this to Komputer Korner a few years ago >>>as well... >>> >>>If you correctly predict your opponent's move at least 50% of the time, or >>>more, then the way we currently ponder can _not_ be improved on. >> >>Not correct. >>There are ways to improve the pondering but not the way that bdann suggested. >> >>For example if your program ponders for the opponent move and fail high and find >>that it is winning after the fail high then it is possible that the program >>expect a blunder and it may be better to go back to the root position to see if >>the opponent has a better move and to ponder for the better move. > > >So? If you are predicting > 50% of the time, then there is not a thing wrong >with sticking with this. It can fail high this iteration, then fail low the >next one. I did not say after every fail high but only after you see that you are winning. it depends on the score. An extreme example is when you see a forced mate after the expected move. In this case you can safely stop pondering on the opponent move and ponder on another move. If you see a score of +20 pawns for yourself you also can go to ponder for another move. I am less sure if it is a good idea to ponder on another move when you see a score of +5 but if you can be sure in 99.9% that you win after seeing +5 score then it can also be a good idea because taking a risk in 0.1% of the cases is not a big risk and the risk that the opponent does not play the predicted move is bigger. > > >> >>Another idea is in cases that the opponent goes for a long think(for example 30 >>minutes at 40/2 hours game) for one move and in this case it may be better to >>stop pondering after the program pondered for enough time and to start pondering >>for the next best move or for the root position. > > >Again, this doesn't work. Given the choice of pondering a move I believe will >be correct over 50% of the time, vs pondering two different moves for 1/2 of >the time, I'll take the former _every_ time. And get my _own_ deep search in >since my opponent thinks something is worth a deep think also. So long as I >predict > 50% of the time there is _no_ better methodology. The difference between 3 minutes of search and 6 minutes of search is more than 1/2 ply assuming a branching factor of 3(log6/log3 plies). The difference between 30 minutes of search and 33 minutes of search is smaller(log33/log30 plies). sacrificing log6/log3 plies for searching another move may be a bad idea but sacrificing only log33/log30 plies for the same target is a better deal. Uri
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