Search found 2825 matches

by Rebel
Sat Apr 07, 2012 3:46 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: futility pruining, razoring question
Replies: 33
Views: 8390

Re: futility pruining, razoring question

Oh by the way the 10 pawn window for alpha was used by Ed, i'd be very careful razoring on alpha indeed as you correctly warn, yet i would start testing the above and do without qsearch first. Only after that test WITH qsearch. It's trivial to test all combinations there though i'd say... In Diep r...
by Rebel
Sat Apr 07, 2012 3:27 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

Of course I agree with you that a faster search should be the end result and for me it does, I am just trying to explain the logic behind the approach. Why does it result in a faster search? Because of testing, what else is the final measurement? You didn't answer the question. WHY would splitting ...
by Rebel
Fri Apr 06, 2012 9:55 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

Of course I agree with you that a faster search should be the end result and for me it does, I am just trying to explain the logic behind the approach. Why does it result in a faster search? Because of testing, what else is the final measurement? You didn't answer the question. WHY would splitting ...
by Rebel
Fri Apr 06, 2012 5:05 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

From the root. The perfect search (except for the best move) goes like this: odd - xxxxxxxxxxxxxxxxxxxxx (all moves searched) (no beta cut-off) even - x (beta cut-off) (only one move searched) odd - xxxxxxxxxxxxxxxxxxxxx (all moves searched) (no beta cut-off) even - x (beta cut-off) (only one move ...
by Rebel
Fri Apr 06, 2012 4:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

Houdini wrote:
Rebel wrote:Of course I agree with you that a faster search should be the end result and for me it does, I am just trying to explain the logic behind the approach.
Why does it result in a faster search?
Because of testing, what else is the final measurement?
by Rebel
Fri Apr 06, 2012 2:22 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

When implementing hash tables in the days that memory was limited (1 Mb if you were rich) I set-up my hash table data structure as follows: - One hash table for odd plies - One hash table for even plies And where ever possible make the odd ply HT twice as big as the even ply HT because that one is ...
by Rebel
Fri Apr 06, 2012 2:10 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

AFAIK i was the first one really using 4 sequential or more probes. Bob described in 90s doing 8 random probes (to avoid chaining), but of course at modern memory systems using more than 1 table is pretty slow and/or gives some overhead. Yes, I think we all have expirimented with the optimal number...
by Rebel
Fri Apr 06, 2012 2:06 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

And so it makes sense to declare a bigger odd-ply-HT than an even-ply-HT. Not really. Number of stores in meaningless. Number of hits is only a little bit less meaningless. What really counts is how much search time the hits save you. When you say 'odd ply', do you mean counted from the root or cou...
by Rebel
Fri Apr 06, 2012 1:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

AFAIK i was the first one really using 4 sequential or more probes. Bob described in 90s doing 8 random probes (to avoid chaining), but of course at modern memory systems using more than 1 table is pretty slow and/or gives some overhead. Yes, I think we all have expirimented with the optimal number...
by Rebel
Fri Apr 06, 2012 1:29 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Hash table division
Replies: 42
Views: 6014

Re: Hash table division

When implementing hash tables in the days that memory was limited (1 Mb if you were rich) I set-up my hash table data structure as follows: - One hash table for odd plies - One hash table for even plies And where ever possible make the odd ply HT twice as big as the even ply HT because that one is ...