I consider that quite plausible. The basic winning idea is not that hard to find, and there really isn't anything else to try. Even lesser grandmasters are darn good calculators when there is only one forcing line to look at and there are no other good candidate moves. I suspect most strong players would play the right moves even at fairly rapid time controls. The only thing to calculate is whether the queen can pull some trick after 4. Bf6, but since there is no other move that really gives white a chance, many would just play the moves to get to this position, and then calculate the rest.
I consider that quite plausible. The basic winning idea is not that hard to find, and there really isn't anything else to try. Even lesser grandmasters are darn good calculators when there is only one forcing line to look at and there are no other good candidate moves. I suspect most strong players would play the right moves even at fairly rapid time controls. The only thing to calculate is whether the queen can pull some trick after 4. Bf6, but since there is no other move that really gives white a chance, many would just play the moves to get to this position, and then calculate the rest.
-Sam
Will your next version of Hannibal be able to find it, by fixing the Null Moves heuristic?
Null Move Heuristic
As mentioned above in the section on Internal iterative Deepening, there is a minimum search tree that can be obtained simply by using conventional alpha-beta pruning methods. However, this limit is not an absolute limit, and can be avoided if one is willing to make one or two sacrifices in search accuracy. One method used to great effect in all strong modern programs is that of NULL move pruning. ColChess does not use this method, but Beowulf does.
Null move pruning is a clever, and relatively recent method first proposed by Donninger (1993). The algorithm is simple, and in fact simply codes a concept that humans have been using for many years without knowing it.
Quiescence Search
The problem with abruptly stopping a search at a fixed depth is something called the 'horizon effect'. It might be that you have just captured an opponent's pawn at depth 0, then you return that score being justifiably proud. However, if you had searched another ply deeper you would have seen that the opponent could recapture your queen!
Full width search is not much different to the original search at depth>0, generating all the possible available moves and testing to see which one is the best.
If I introduce the FEN code of the correct move (Bf8+), it sees that white is winning almost instantly (please not that I wrote the FEN manually, so it may contain typos):
pichy wrote:This is where top GMs are superior to top engines in long term calculation and able to detect a position that will lead the human to win at the end by forcing Black into a Horizon effect in which Black will not be able to get out off.
Very nice position!
Stockfish currently can't find it within reasonable time, but, with this patch: https://github.com/glinscott/Stockfish/ ... inned_null, here is how it looks. The change was pretty minor. Adding a bonus when a friendly piece is blocking check to the enemy king, and not allowing null move pruning for the enemy in that situation. Whether it ends up increasing ELO or not is a separate question .
pichy wrote:
Will your next version of Hannibal be able to find it, by fixing the Null Moves heuristic?
I haven't tried it with my development version, but I doubt it gets it, and it is probably not that far from release, maybe a couple of months. Its one of those positions that sadly the programmer is still better at than the program.
I am playing with null move a little right now in fact, but experience indicates I am unlikely to get away with changing it dramatically without weakening the engine.
pichy wrote:
Will your next version of Hannibal be able to find it, by fixing the Null Moves heuristic?
I haven't tried it with my development version, but I doubt it gets it, and it is probably not that far from release, maybe a couple of months. Its one of those positions that sadly the programmer is still better at than the program.
I am playing with null move a little right now in fact, but experience indicates I am unlikely to get away with changing it dramatically without weakening the engine.
-Sam
I don't believe that Null Move will weakening your engine since the best engines Houdini and Critter are benefitting from using it
Can you make this version available as a download?
gladius wrote:
pichy wrote:This is where top GMs are superior to top engines in long term calculation and able to detect a position that will lead the human to win at the end by forcing Black into a Horizon effect in which Black will not be able to get out off.
Very nice position!
Stockfish currently can't find it within reasonable time, but, with this patch: https://github.com/glinscott/Stockfish/ ... inned_null, here is how it looks. The change was pretty minor. Adding a bonus when a friendly piece is blocking check to the enemy king, and not allowing null move pruning for the enemy in that situation. Whether it ends up increasing ELO or not is a separate question .