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Subject: Free advice from Eartjbest chess programmer!

Author: Roy Eassa

Date: 12:39:35 03/17/02

Go up one level in this thread



Folks, this is free advice from arguably the best chess programmer on Earth!



On March 17, 2002 at 09:17:07, Christophe Theron wrote:

>On March 17, 2002 at 02:13:22, Uri Blass wrote:
>
>>On March 16, 2002 at 22:29:26, Christophe Theron wrote:
>>
>>>On March 16, 2002 at 15:01:04, Uri Blass wrote:
>>>
>>>>On March 16, 2002 at 14:34:13, Jorge Pichard wrote:
>>>>
>>>>>On March 16, 2002 at 14:26:20, Jorge Pichard wrote:
>>>>>
>>>>>>In the first game Chess Tiger 14.9 was playing without using its Turbo Mode, in
>>>>>>which it enables it to think on its opponent time to move. Now I activated Turbo
>>>>>>Mode, but I am still playing Using my handspring at 32 Mhz without using
>>>>>>Afterburner or Fastcpu. This time the Tiger was hungry and decided to grab a
>>>>>>Gaviota for lunch.
>>>>>
>>>>>PS: Gaviota is playing the ending terrible, but nextgame I will continue vs Gnu
>>>>>Chess v5.02 Est rating of 2225.
>>>>
>>>>Some details:
>>>>
>>>>Gaviota is estimated to have rating of 2170 when GNU chess5.03 is estimated to
>>>>have rating of 2150
>>>>see http://f11.parsimony.net/forum16635/messages/23352.htm
>>>>
>>>>I do not know GNUchess5.02 but I doubt if it is better than Gaviota.
>>>>
>>>>Gnu chess played in the 3th division based on the history pages of Leo when
>>>>gaviota scored clearly better than GNUchess.
>>>>
>>>>I admit that it was not GNUchess5.02 but I do not know if there is a big
>>>>difference between 5.00 and 5.02
>>>>
>>>>
>>>>
>>>>I think that it may be more interesting to see programs of CCC memebers and not
>>>>GNUchess.
>>>>
>>>>possible candidate is Averno
>>>>
>>>>The author of faile also posted in the past(faile is clearly weaker than
>>>>gaviota)
>>>>
>>>>My program may be also a candidate
>>>>
>>>>Today I believe that it is only in similar level to faile but I plan to do it
>>>>stronger and it is going to be available in april.
>>>>
>>>>Uri
>>>
>>>
>>>
>>>It is interesting to see the progress of somebody who has been suggesting
>>>improvements to programmers for a long time, and has eventually decided to try
>>>them himself.
>>>
>>>I'm glad to see that you are writing your own chess program. I'm sure it will
>>>have some unique features, and that's good. I would recommend you to reinvent
>>>the wheel and not create yet another Crafty clone. It will not be a waste of
>>>time. It is how things were in the eighties, and it was a great time for
>>>computer chess.
>>>
>>>My best wishes to... Huh... Have you chosen a name for your chess program?
>>>
>>>
>>>
>>>    Christophe
>>
>>
>>Movei is the name of it.
>>
>>The latest tested version  has only a piece square table evaluation with no book
>>and no hash table.
>>
>>The piece square table is only changed in the endgame.
>
>
>That's good enough as a first step. You can build a reasonably strong chess
>program with PSTs. It gives you a reasonably good evaluation (assumig your PSTs
>are OK) and you can focus earlier on most important things.
>
>
>
>
>>It can be improved by better order of moves and it can be also improved by
>>better extension and pruning rules(it is using only some futility pruning today
>>and it does not use partial extensions)
>
>
>Chess Tiger does not use fractional extensions either. I just use more detailed
>rules for extensions and I decide to extend or not. That's 1 or 0.
>
>
>
>
>> but inspite of all the problems the
>>latest version could beat Faile with no book 6-4 in a match(time control was 1
>>minute/40 moves,2 minutes/40 moves...5 minutes/40 moves)
>>
>>It also lost 8.5-1.5 in a match against GNUchess5.03 in the same conditions.
>>hardware was one pIII800.
>>
>>I believe that Faile and Gnuchess used hash tables in the matches(I told them no
>>instruction about it but usually programs with hash tables use some hash tables
>>by the default option)
>
>
>Some advices for you:
>
>1) play fast games, manually, preferably on slow hardware. So the mistakes of
>your program do not get hidden in very long PVs and you can more easily
>understand what went wrong.
>
>2) Select an opponent only slightly stronger than your program. If your opponent
>is too strong you learn almost nothing because both your evaluation and search
>get badly beaten. You are just disgusted by the result and do not know what to
>do. When you have improved, change to a stronger opponent.
>
>3) You'll soon discover that whatever you add in your evaluation, if your
>opponent oursearches you there is nothing you can do: you lose. You will
>probably have to spend months or even years improving your search algorithms in
>order to avoid this. That's why I think that a PST program is OK to start with.
>Don't make the mistake to try to add special cases in your evaluation in order
>to cover your search's deficiencies. If you want you can add terms to evaluate
>the tactical pressure on each side (couting the number of attacks for example),
>but these terms must be kept general. Don't add code like "if black rook in a8
>and black king in e8 and white knight on c7 then add penalty to black score".
>That does not work.
>
>4) Don't try to fix a weakness as soon as you discover it. Just say "that's
>life". Fix it only if it happens over and over again. Generally, start by fixing
>the most obvious and big mistakes. Don't try to stuff in high level knowledge
>too early in your developpement. You can't run if you do not even know how to
>walk. This point is the reason why I believe that being a very strong chess
>player is a handicap for a chess programmer (at least in the begining).
>
>5) Make a backup of your sources at least every day. Use an automatic utility or
>a batch file to compress all your *.c and *.h to another directory on your hard
>disk every time you boot your computer. The name of the compressed file must be
>different every day, so you can on demand retrieve last month's source if
>necessary. I currently have on my hard disk the last 502 versions of Chess
>Tiger, the oldest being 2 years old. It takes 144Mb of disk space. I have
>written an utility that does that. It runs in a DOS box and calls PKZIP to do
>the compression job. I can send it to you if you have some use for it.
>
>6) Don't follow my advices. Do it your way for a while, then read these advices
>again. Their meaning should become obvious then, and some of them might not even
>apply to you. :)
>
>7) Good luck!
>
>
>
>    Christophe



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