Jacques Basaldúa, I say that adding superko adds 6% or so for 2 reasons. About 2% is adding it to the hash table. About 4% is computing the zobrist hash, which is mainly used for superko.
Another cost is undo. Superko requires undo, unless you want store a hash value with each chain of stones. I am not sure exactly what undo costs, but lets say 5% to 10%. I do local analysis, so I pay for undo anyways. But, if you were doing MC only, then you could go 5% to 15% faster if you remove superko checking and undo. Michael Wing > Michael Wing wrote: > > > In my program (which implements undo), the cost of > > for suicide detection is around 1%, which means it > > would lose 1.5 ELO points. > > In programs that somehow maintain lists of legal moves > or even probability distribution functions over the legal > moves, avoiding suicide is free. I fact, adding the > suicide move to the list would cost. > > > On the other hand detecting superko costs more like > > 6% or so, which costs 9 or more ELO. So a benefit > > of 1 ELO for doing superko right may not be worth > > the cost. > > I guess you mean a bullet proof test from the beginning > of the game. I only test the last 7 moves (if enabled, > it can also be disabled) and that does not cost much. > > The reasons why I use 7 moves are 2: > > * I have never found among strong players a need for > repetition other that triple ko and double ko on a > group with no eyes. (Both are 6 moves long.) My point > is: If the program is so weak that it does silly > repetitions, improve something else. If it is so strong > that it has the same problems as strong humans, detect > superko. > > * My hash system can use only half of the hash (32 bits) > and detect the collision with probability 1. (Because of > the properties of the keys, you need at least 8 keys > for a combination of keys giving zero.) > > A reason I can figure for ignoring repetition in the > playouts is: If the playouts are random, it won't happen > much anyway. The probability of a repetition of 6 random > moves is too small to care about. But in real play it is > frequently a fight for the game. The player forced to > avoid the repetition will resign if it is about the > life of a big group. > > > Jacques. > > > _______________________________________________ > computer-go mailing list > [email protected] > http://www.computer-go.org/mailman/listinfo/computer-go/ > -- _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
