With kind regards,
Matt
Brute Force
Moderator: Ras
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Liegs
Brute Force
Are there any (even fairly strong) free engines that allow one to set an option to have it still do evals, but search brute force (everything). I think this means no extensions but I am not sure
With kind regards,
Matt
With kind regards,
Matt
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Eelco de Groot
- Posts: 4681
- Joined: Sun Mar 12, 2006 2:40 am
- Full name: Eelco de Groot
Re: Brute Force
Hello Matt,
There used to be an option to do this in old Rebel. I am not sure if something like this can be done in the last Pro Deo programs from Ed Schröder who also programmed Rebel. It was possible to switch off a lot of reductions and to switch off just about all extensions in Pro Deo 1.2 that would come close to being a totally brute force program again.
I believe that in a modern program, but opinions may differ about this, you can have a design philosophy that no line should be completely closed to searching it further. Well to a degree at least, lines that give up only material but take nothing back for instance, but those run out of pieces to give away, so they stop there hopefully when the lone King gets mated. Unless your program is very very buggy...
Other lines will repeat the same moves indefinitely, those lines are a problem for the search too.
Vasik Rajlich said in his forum that, if you had a program that stopped looking into certain lines, you would quickly find that you did not like this program.
So the design philosophy of most programs and of Rybka I think then also, is to reduce lines, limit depth of search, but never completely prune them.
Christophe Théron on the other hand stated here once that, before Chess Tiger 2007, his program did not do any reductions! So I suppose that constitutes the opposite view; that some lines are so obviously bad, no human player would look any further. So a good program should not do either.
This is just a very non-technical interpretation of mine, I have not really studied this in any program. You would have to ask the experts!
The distinction between pruning and reducing is a matter of degree in some sense of course, in the limit they are the same, but it seems an interesting discussion point still!
Regards, Eelco
There used to be an option to do this in old Rebel. I am not sure if something like this can be done in the last Pro Deo programs from Ed Schröder who also programmed Rebel. It was possible to switch off a lot of reductions and to switch off just about all extensions in Pro Deo 1.2 that would come close to being a totally brute force program again.
I believe that in a modern program, but opinions may differ about this, you can have a design philosophy that no line should be completely closed to searching it further. Well to a degree at least, lines that give up only material but take nothing back for instance, but those run out of pieces to give away, so they stop there hopefully when the lone King gets mated. Unless your program is very very buggy...
Other lines will repeat the same moves indefinitely, those lines are a problem for the search too.Vasik Rajlich said in his forum that, if you had a program that stopped looking into certain lines, you would quickly find that you did not like this program.
So the design philosophy of most programs and of Rybka I think then also, is to reduce lines, limit depth of search, but never completely prune them.
Christophe Théron on the other hand stated here once that, before Chess Tiger 2007, his program did not do any reductions! So I suppose that constitutes the opposite view; that some lines are so obviously bad, no human player would look any further. So a good program should not do either.
This is just a very non-technical interpretation of mine, I have not really studied this in any program. You would have to ask the experts!
The distinction between pruning and reducing is a matter of degree in some sense of course, in the limit they are the same, but it seems an interesting discussion point still!
Regards, Eelco
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Stan Arts
Re: Brute Force
Generally I believe brute force means searching anything within reported searchdepth in alpha-beta, without pruning or reducing any lines. "Sound" searching.
My program has such an option,
In my program it disables reductions such as nullmove and other pruning, but leaves extentions and tactical tricks in Q-search enabled. So it still might find a lot of tactics deeper then the full-width searchdepth reported.
It means reported searchdepth gets searched with pure alpha-beta, finding anything (including zugzwang, etc.) within the depth reported.
In blitz it doesn't even play so bad, but at longer timecontrols in middlegame runs into a "brick wall" at around depth 8. Where with brute-force turned off it will go on to reach depth 10-11, etc.
Stan
My program has such an option,
In my program it disables reductions such as nullmove and other pruning, but leaves extentions and tactical tricks in Q-search enabled. So it still might find a lot of tactics deeper then the full-width searchdepth reported.
It means reported searchdepth gets searched with pure alpha-beta, finding anything (including zugzwang, etc.) within the depth reported.
In blitz it doesn't even play so bad, but at longer timecontrols in middlegame runs into a "brick wall" at around depth 8. Where with brute-force turned off it will go on to reach depth 10-11, etc.
Stan
Liegs wrote:Are there any (even fairly strong) free engines that allow one to set an option to have it still do evals, but search brute force (everything). I think this means no extensions but I am not sure
With kind regards,
Matt