Re: Is chess programming now boring ???
Posted: Fri Mar 29, 2024 7:10 pm
From "Giraffe: Using Deep Reinforcement Learning to Play Chess" by Matthew Lai
"We also investigated the possibility of using probability thresholds instead of depth
to shape search trees. Depth-based searches form the backbone of virtually all chess
engines in existence today, and is an algorithm that has become well-established over
the past half century. Preliminary comparisons between a basic implementation of
probability-based search and a basic implementation of depth-based search showed that
our new probability-based approach performs moderately better than the established
approach. There are also evidences suggesting that many successful ad-hoc add-ons to
depth-based searches are generalized by switching to a probability-based search. We
believe the probability-based search to be a more fundamentally correct way to perform
minimax.
Finally, we designed another machine learning system to shape search trees within
the probability-based search framework. Given any position, this system estimates the
probability of each of the moves being the best move without looking ahead. The system
is highly effective - the actual best move is within the top 3 ranked moves 70% of the
time, out of an average of approximately 35 legal moves from each position. This also
resulted in a signficant increase in playing strength.
With the move evaluator guiding a probability-based search using the learned evaluator,
Giraffe plays at approximately the level of an FIDE International Master (top
2.2% of tournament chess players with an offcial rating)12."
1
"We also investigated the possibility of using probability thresholds instead of depth
to shape search trees. Depth-based searches form the backbone of virtually all chess
engines in existence today, and is an algorithm that has become well-established over
the past half century. Preliminary comparisons between a basic implementation of
probability-based search and a basic implementation of depth-based search showed that
our new probability-based approach performs moderately better than the established
approach. There are also evidences suggesting that many successful ad-hoc add-ons to
depth-based searches are generalized by switching to a probability-based search. We
believe the probability-based search to be a more fundamentally correct way to perform
minimax.
Finally, we designed another machine learning system to shape search trees within
the probability-based search framework. Given any position, this system estimates the
probability of each of the moves being the best move without looking ahead. The system
is highly effective - the actual best move is within the top 3 ranked moves 70% of the
time, out of an average of approximately 35 legal moves from each position. This also
resulted in a signficant increase in playing strength.
With the move evaluator guiding a probability-based search using the learned evaluator,
Giraffe plays at approximately the level of an FIDE International Master (top
2.2% of tournament chess players with an offcial rating)12."
1