Author: Eelco de Groot
Date: 22:58:17 05/08/00
Go up one level in this thread
I keep referring people to the CCC Database Navigator at the Yellow Bishop Computer Chess Club but then we never hear from them again. So I hesitate a little to give this link: http://ybishop.cjb.net/. Is there perhaps a minotaur lurking in those vast archives? I haven't gotten this program to run very well myself so I can't give much advice, Steve. What I do now is unzip the downloaded archive to textfiles in a separate directory. Then I go in Dos to that DirectoryX and give something like C:\DirectoryX> COPY *.TXT NEW.TXT and then view this big NEW.TXT in Word Pad. (DirectoryX and NEW.TXT are just example names). If somebody has a better way of doing this I would like to hear about it. Regards, Eelco Some of those messages by Stephen Ham and the replies: -------------------------------------------------------------------------------- Subject: Re: Computer Correspondence Chess Challenge From: Robert Hyatt E-mail: hyatt@crafty.cis.uab.edu Message Number: 104177 Date: April 01, 2000 at 12:46:58 In Reply to: Re: Computer Correspondence Chess Challenge Message ID: 104158 Posted by: blass uri At: blass_n@netvision.net.il On: April 01, 2000 at 10:32:52 On April 01, 2000 at 10:32:52, blass uri wrote: >On March 31, 2000 at 23:17:45, Robert Hyatt wrote: > >>On March 31, 2000 at 12:53:43, Stephen Ham wrote: >> >>>Dear Readers, >>> >>>I know many of you are actively following my ongoing match games versus Fritz 6a >>>and Nimzo 7.32. For those of you not familiar with the event, please visit: >>> >>>http://correspondencechess.com/campbell/index.htm >>> >>>Anyway, a frequent poster here (name is withheld) wrote to Mr. Campbell stating >>>that since the chess engines are displaying their top 3 choices, they are being >>>weakened "a lot". No explanation was given for that claim. >>> >>>Would somebody here please provide a detailed explanation regarding whether this >>>claim is correct and why? >> >> >>It depends on how they compute these variations. Done correctly, it is >>_horribly_ inefficient. If you watch a normal search, the first move will >>usually take over 50% of the total time. The remaining N-1 moves take the >>remaining 50% of the time. If you have it display two 'best'moves, you >>increase the total search time by roughly 50%. The first move takes the >>same time as before. The second move also takes the same time as before, >>and the final N-2 moves take just a tad less than before. Net loss is >>ugly. If you have it display the best 3 moves, you slow it down by exactly >>a factor of two... >> >> >> >> >>> >>>The chess engines are on settings recommended by ChessBase USA as their optimal >>>settings for this event. My extremly limited understanding is that displaying >>>the top 3 choices does indeed affect the chess engines, but it causes them to >>>spend more time on what it believes to be the 3 best moves. As such, this sounds >>>like an enhancement to me. Given that the chess engines are allowed about 24 >>>hours calculation time on weekdays and are searching to 16-18 ply, I can't >>>imagine that this weakens them in any way. >> >> >>Each iteration will take about 2x longer than the previous. Rather than >>a branching factor of 3x, you raise it to 6x. This will cost several plies >>over 24 hours. > >My experience with chessbase engines show that it is not the case. >I also see no reason that the branching factor will change. > >The program is going to be slower by a constant factor by calculating the first >3 moves. >The only difference relative to calculating only the best move is that you need >to use time to calculate the second best move and the third best moveand I do >not see a reason to be more than 3 times slower. > >The only case when the branching factor is going to be bigger is if you generate >a tree of moves and not only the best 3 moves. > >Uri The term "branching factor" has two uses: (a) the correct one is that it is the number of branches at the 'typical' node in a tree. No one uses it like this any longer although it is the correct usage. (b) the typical one is that it is the ratio of the time for T(n)/T(n-1) (time for iteration n divided by the time for iteration N-1). I inaccurately used a combination... clearly iteration N will take 2x (or more) longer than normal. But then so will iteration n-1. But in any case, a factor of 2-3 is a ply. And every ply helps... -------------------------------------------------------------------------------- Subject: Computer Correspondence Chess Challenge From: Stephen Ham E-mail: Steve.Ham@gecapital.com Message Number: 104676 Date: April 05, 2000 at 12:05:16 Dear Readers, Thanks for the valuable input from your replies to my earlier post. I can now officially state that my silicon opponents, Fritz 6a and Nimzo 7.32 will no longer display their 2nd and 3rd move selections in their correspondence match games with me, on a go forward basis. We always intended to give the chess engines optimal conditions. We now understand that over a 24 hour period, they may now be able to search another ply deeper, say from 18-ply to 19-ply, which is deemed to be meanigful. Also, the fear that many Correspondence Chess players have, of playing a weak human who relies entirely upon top quality hardware/software, can now be tested. We presume that such a weak player, knowing his/her limitiations, would not care what moves the computer rejects and only wants the strongest move found after calculating for 24 hours or so. Thus our experiment now follows that path. While my commentary to the match now loses the ability to comment upon the chess engines candidate moves, we get even stronger opposition...we lose something entertaining but gain something more meaningful (read: stronger). Here's a group thank you to those who contributed their knowledge. Thank you! Stephen Ham -------------------------------------------------------------------------------- Subject: Re: Correspondence Challenge: current positions From: Stephen Ham E-mail: Steve.Ham@gecapital.com Message Number: 106072 Date: April 14, 2000 at 16:42:03 In Reply to: Re: Correspondence Challenge: current positions Message ID: 105981 Posted by: James Robertson At: jrobertson@newmail.net On: April 14, 2000 at 02:12:07 Dear Jouni, Dann, James and others, Thanks for your interest in the Computer Correspondence Chess Challenge! Yes, I too think the chess engines have indeed performed well to date. I confess they have done much better that I ever expected. However, I just sent my move in for Fritz 6a-Ham and Fritz 6a now admits it is clearly inferior. I think I have a large advantage now...one that might be winning with the proper technique. My move (29...Qxb2) and commentary will likely be posted late tonight (4/14) or tomorrow morning. Perhaps I'm the only one who doesn't think that Ham-Nimzo 7.32 is better for Black, Nimzo 7.32 "thinks" is has a large advantge. I'm curious what Nimzo "sees" now, because I think I have the easier part of equality since I see lot's of places where it can err. It is a very complex position, however, as both sides have played sharply and unbalanced the position to obtain dynamism. My fear though, is that with the chess engine's 20 ply searches, that possibly I'm the one missing something. We'll all know for sure in a few more days. Jouni, regarding the "non-optimal 3-variation mode", as you know the chess engines are now only displaying the primary mode. The search depth deepened by 1-2 ply from 17-18 ply to 19-20 ply, but this may be partly due to reduced material on the board. I think Dan is absolutely correct about the transition to endgame "like" positions. I sense that the chess engines have recently played less than optimal moves in that transition. Hopefully I can exploit this. I should point out that the chess engines have been out of their deep opening books for, on average, only about 12 moves. Nimzo 7.32 especially stayed in safe main line opening theory, so it couldn't get hurt quickly. Ham-Fritz 6 could have been an early win for me, had I not played like the human that I am and goofed my move order up, giving the computer a saving defense. Meanwhile, I think I gradually outplayed Fritz as Black once it left the safety of its opening book. In summary, given their deep opening books and great tactical skills combined with fantastic search depth, it's unrealistic to expect me to quickly win. My style is more technical than tactical, involving the gradual accumulation of small positional advantages. Therefore, these games still have a lot of play left. I just hope to be able to hold my head up high and still post here, regardless of the result! I still think I will win the match, but I'm now quite impressed by how strong these monsters are. Stephen Ham --------------------------------------------------------------------------------
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