Author: Vasik Rajlich
Date: 05:31:27 03/10/05
Go up one level in this thread
On March 09, 2005 at 22:30:05, Alex Newman wrote: >On March 09, 2005 at 22:10:58, Robert Hyatt wrote: > >>On March 09, 2005 at 21:19:51, Alex Newman wrote: >> >>>On March 09, 2005 at 21:12:52, Michael Yee wrote: >>> >>>>On March 09, 2005 at 20:27:09, Alex Newman wrote: >>>> >>>>>I can take the source code of Crafty and make an engine stronger then Crafty in >>>>>less then a week. >>>> >>>>Not to be (too) confrontational, but have you actually accomplished this feat, >>>>say, in a private experiment? >>>> >>>>There was someone here a while ago who was trying to get people to bet him a >>>>large sum of money that he couldn't improve crafty by some amount of points >>>>(maybe 100?). >>>> >>>>I'm skeptical of these kind of claims because if it were possible to improve >>>>crafty by that much, it would almost be commercial strength (according to WBEC >>>>ratings)... So why wouldn't that person just write a commercial-level engine >>>>from scratch (given that he has the last "secrets" anyway)? >>>> >>>>Michael >>> >>>I didn't say 100 ELO. I just said 'improve'. >>>No, I didn't try it. But try adding checks in quiescent, history and better >>>futility pruning, and you should get at least 30 ELO. >>>I think Crafty could be better in tactics. >> >> >>1. crafty uses history. always has. >> >>2. older versions used checks in q-search. you can see from the comments in >>main.c when they were removed. The version with was absolutely no better than >>the version without, and the code was simpler without. >> >>3. "better futility pruning" I don't know about. It is already risky enough, >>but who knows what can be improved there... > >Thanks for the answer Prof. Hyatt. I have a great respect for you and Crafty. > >- By history pruning, I mean reducing search depth for moves with low history >value (many conditions apply of course). I know Crafty uses history for move >ordering, but am not aware you use it for pruning (didn't check the most recent >Crafties). > >- It's seems to be common experience shared by many that checks in q-search help >tactics, but again they shouldn't be done always. Some think that using always >R=3 and checks in q-search for null moves only is a good idea. > >- By better futility pruning, I mean doing pruning for nodes other then leafs, >but with much higher material margin. Crafty's approach is better than it might look. Quite a bit of "intelligence" in an engine is actually counterproductive .. Vas
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