Author: José Carlos
Date: 08:30:48 01/07/04
Go up one level in this thread
On January 07, 2004 at 10:57:41, Robert Hyatt wrote: >On January 06, 2004 at 17:36:05, José Carlos wrote: > >>On January 06, 2004 at 16:24:07, Robert Hyatt wrote: >> >>>On January 06, 2004 at 14:58:38, Anthony Cozzie wrote: >>> >>>>On January 06, 2004 at 14:32:58, Slater Wold wrote: >>>> >>>>>On January 05, 2004 at 08:48:23, José Carlos wrote: >>>>> >>>>>> Hi, I'd like to try singular extensions in my program. I've been trying to >>>>>>think about it and all my tries so far result in worse performance. After some >>>>>>web search I haven't been able to find anything but the general idea described. >>>>>> Is there any good description somewhere? Some pseudo-code? I guess there must >>>>>>be something interesting in the archives but I can't download all of them. >>>>>> Thanks in advance, >>>>>> >>>>>> José C. >>>>> >>>>>SE and nullmove do not mix. And that's straight from Hsu. From speaking with >>>>>him (via e-mail), I gathered that this would be his approach using nullmove, and >>>>>I tried it in Crafty with very nominal success: >>>> >>>>they seem to work just fine in Ferret, arguably the strongest tactical program >>>>out there. >>>> >>>>anthony >>> >>>Yes, but Ferret is not using Hsu's Singular Extension algorithm. not even >>>close. Bruce is using a "SE approximation" that works very well, but it is >>>not to be confused with what Hsu defined as singular extensions. >> >> Is this approximation similar to the one Bas describes in other post? If not, >>could you please describe (if you know) what is Bruce doing? I would like to >>implement Bas' idea, a small modificacion I figured out, and any other known >>approach, and then post the comparison here. >> >> José C. > >I believe it is similar. I have an old "Singular()" function that I could >make available if you want to look at it. Note that it "fits" Crafty, and >would obviously need changes for other programs, but the comments and basic >structure would be a starting point. I'm not sure how well it works, but I >believe I have the code stuck away if anyone is interested... > >Bob > >BTW what this is is a piece of code you would call where appropriate. It does >the singular-test search, and if it is convinced one move is better than the >rest by a wide margin, it returns that move, which your search function will >then have to recognize during the normal search, and extend it. I probably >should put this into Crafty and make it a compile-time option, but I am not >sure how easy that would be with the SMP stuff that was done _after_ the >Singular() function was written. My structure is totally different from Crafty, but I'd appreciate a lot if you sent me the code. I don't mind if it doesn't compile in Crafty. Actually, I've read Crafty's code, but never compiled it. I have a million comments in spanish all across Crafty's code though... :) José C. >> >> >>>I did the full DB implementation in Cray Blitz, and using non-recursive >>>null-move R=1, it seemed to work pretty well. I have tried it more than >>>once in Crafty, and it simply did not work reasonably whatever I tried. I've >>>not decided that it is hopeless, but I have not played with it further in at >>>least a couple of years now... I came to the same conclusion that somehow, >>>null-move with bigger R values simply doesn't work very well. You extend, but >>>null-move reduces the depth and things get lost in the middle.
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