Author: Christophe Theron
Date: 13:21:10 07/20/02
Go up one level in this thread
On July 20, 2002 at 16:02:54, Ricardo Gibert wrote: >On July 20, 2002 at 15:37:00, Christophe Theron wrote: > >>On July 19, 2002 at 23:12:28, Ricardo Gibert wrote: >> >>>On July 19, 2002 at 23:08:16, Robert Hyatt wrote: >>> >>>>On July 19, 2002 at 22:15:31, Ricardo Gibert wrote: >>>> >>>>>On July 19, 2002 at 21:43:40, Robert Hyatt wrote: >>>>> >>>>>>On July 19, 2002 at 15:50:44, Uri Blass wrote: >>>>>> >>>>>>>On July 19, 2002 at 15:25:48, Christophe Theron wrote: >>>>>>> >>>>>>>>On July 18, 2002 at 12:14:10, Robert Hyatt wrote: >>>>>>>> >>>>>>>>>On July 18, 2002 at 05:58:56, Vincent Diepeveen wrote: >>>>>>>>> >>>>>>>>>>On July 17, 2002 at 13:18:40, Christophe Theron wrote: >>>>>>>>>> >>>>>>>>>>>On July 16, 2002 at 11:01:23, Vincent Diepeveen wrote: >>>>>>>>>>> >>>>>>>>>>>>On July 15, 2002 at 13:11:09, Christophe Theron wrote: >>>>>>>>>>>> >>>>>>>>>>>>>On July 15, 2002 at 08:37:34, Omid David wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>>I don't think using double null-move is a good idea in practice, since in >>>>>>>>>>>>>>midgame the chance of zugzwang is negligible and thus it's superfluous (I doubt >>>>>>>>>>>>>>if even DIEP uses it). However the contribution of double null-move is that it >>>>>>>>>>>>>>gives legitimacy to the null-move pruning idea, proving that it _is_ a correct >>>>>>>>>>>>>>search method (anyway, no one doubts null-move nowadays). >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>>Why does double null move prove that null move is a correct search method???? >>>>>>>>>>>>> >>>>>>>>>>>>>Doing two null moves in a row means going back to standard search (a search not >>>>>>>>>>>>>involving an illegal move like null move is). >>>>>>>>>>>>> >>>>>>>>>>>>>I fail to see how it legitimates null move. >>>>>>>>>>>> >>>>>>>>>>>>Double nullmove legitimates (duh can't you use easier to spell words) >>>>>>>>>>>>itself, for the obvious reason that it is provable now that a search >>>>>>>>>>>>depth of n ply, where i may pick n, is going to solve any problem you >>>>>>>>>>>>give it. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>>OK, I see now. >>>>>>>>>>> >>>>>>>>>>>However, it is not true. >>>>>>>>>>> >>>>>>>>>>>Due to a nasty interaction with the hash table algorithms, just allowing 2 null >>>>>>>>>>>moves in a row will NOT solve any problem. >>>>>>>>>> >>>>>>>>>>What you refer to is a practical impossibility (assuming you have >>>>>>>>>>a efficient search) : >>>>>>>>>> >>>>>>>>>> your assumption is that from a root position r >>>>>>>>>> with transition of some moves to position p, side stm to move and >>>>>>>>>> depthleft=d: >>>>>>>>>> >>>>>>>>>> r ==> p(stm,d) >>>>>>>>>> >>>>>>>>>> that you visit this position with properties that >>>>>>>>>> before this move you have made 1 nullmove or less. >>>>>>>>>> >>>>>>>>>> so ==> r , nullmove , p >>>>>>>>>> >>>>>>>>>> Now a major problem for such an event to occur is that >>>>>>>>>> after 1 nullmove, sides change the side to move. >>>>>>>>> >>>>>>>>>Why is this a problem? IE in my case, position P reached thru a path >>>>>>>>>with a null-move and position P reached thru a path without null-move >>>>>>>>>are _unique_ positions... >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>If so, your programs loses a lot of opportunities to prune because it detects >>>>>>>>less transpositions. But maybe it avoids some problems and is benefical in the >>>>>>>>end, I do not know. >>>>>>> >>>>>>>How much do programs earn by pruning based on hash tables? >>>>>>> >>>>>>>Today I do not use hash tables to prune the tree. >>>>>>>I am interested to know how much rating programs earn from >>>>>>>using hash tables to prune the tree. >>>>>>> >>>>>>>1)Did someone do the experiment of comparing the rating of >>>>>>>a chess program when hash tables are used only for things like order >>>>>>>of moves and the rating of the same program when hash tables are used also for >>>>>>>also to prune the tree. >>>>>>> >>>>>>>2)How much speed improvement do programs get in middle game >>>>>>>from pruning based on hash tables? >>>>>>> >>>>>>>Uri >>>>>> >>>>>> >>>>>>Try position fine 70 with and without. Without you might get to depth 15 >>>>>>or so. With it you can reach depth 40. A _significant_ gain... >>>>> >>>>>You're trying to drive Uri crazy aren't you? >>>>> >>>>>Did you really think Uri could not think of an example of a position where >>>>>having hash tables makes a significant difference? >>>>> >>>>>Do you really think being able to search a position like Fine 70 to a depth of >>>>>40 instead of 15 will make a difference in a programs playing strength? >>>>> >>>>>Don't you realize people are liable to react to such a reply as yours above as a >>>>>troll? >>>>> >>>>>Please try to be a bit more thoughtful. >>>> >>>> >>>>There was _no_ troll involved. Point by point. >>>> >>>>fine 70 _is_ an important hash test. It represents a near-best-case for >>>>hashing. Which is the best you can do. It increases the search depth by >>>>at least a factor of 3x in terms of plies searched. >>>> >>>>Will that help the program? Clearly in king and pawn endings I see 20+ ply >>>>searches _all_ the time. And _that_ definitely helps for those positions where >>>>K+P endings are reached. >>>> >>>>But if you want to take a middlegame position, hashing is worth at least a >>>>factor of 2x based on tests I have run in the past. I can always run them >>>>again. >>>> >>>>So to summarize, fine 70 was and is legitimate. It _clearly_ shows that >>>>hashing makes a significant difference. I hardly see why _your_ post wouldn't >>>>be considered a "troll" in fact. As it attacks a legitimate point in a >>>>utterly simplistic and wrong context... >>>> >>>>Perhaps you should follow your own advice and try to be more thoughtful. >>>>_prior_ to posting??? >>> >>>I did. You didn't...again. >> >> >> >>Bob's post (the one you originally responded to) was perfectly fine. He just >>gave a meaningful information. >> >>Your posts are really borderline. I really fail to see what is the problem with >>Bob's post. >> >>Please don't start a war here. There is really no point. >> >> >> >> Christophe > >I'm perplexed as to why you would take RHs side in this. My post was pretty mild >compared to some of the others that get posted here without rebuke from a >moderator including some of your own posts. I can only conclude that it is due >to RH's status in this forum. So be it. I will make no further posts in this >thread. No it's just that I see that this is going to degenerate pretty quickly into name-calling due to Bob's nature and your -in my opinion- unjustified comment. Yes your comment was mild, but it was not justified (again, in my opinion). I know Bob is going to react very harshly, and before he does I prefer to ask the one who was wrong (you, in my opinion) to reconsider. If I don't act immediately I will have to moderate Bob, and I'm not sure what is going to happen then. :) Christophe
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.