Computer Chess Club Archives




Subject: Re: listing a few beginner bugs in Omids 'research'

Author: Dann Corbit

Date: 17:08:37 12/17/02

Go up one level in this thread

On December 17, 2002 at 20:03:24, Rolf Tueschen wrote:
>On December 17, 2002 at 19:36:59, Dann Corbit wrote:
>>On December 17, 2002 at 19:16:26, Vincent Diepeveen wrote:
>>>On December 17, 2002 at 18:21:28, Uri Blass wrote:
>>>>On December 17, 2002 at 18:11:20, Vincent Diepeveen wrote:
>>>>>On December 17, 2002 at 17:30:36, Bruce Moreland wrote:
>>>>>if you go back in time a bit you see that i had
>>>>>major problems with Omids article and posted it here.
>>>>>there is more than just the problems you see there.
>>>>>also look at his homepage and get the positions he tested
>>>>>and then look to his node counts. for a mate in 2 position
>>>>>where i need like a couple of hundreds of nodes to get to 10 ply
>>>>>he needs 10 million nodes. then R=3 reduces that more.
>>>>>also his implementation is buggy of course. it doesn't take into
>>>>>account problems with transpositions. a classical beginners problem.
>>>>>But most important is that verification search is not something new
>>>>>it is a buggy implementation of something already described years ago
>>>>>with only 'novelty' that omid turns off nullmove *completely*
>>>>>after he finds a nullmove failure.
>>>>No he does not.
>>>>There is no point in the tree that he turns off nullmove completely.
>>>>>All with all a very sad article. The only good thing about it is
>>>>>the quantity of tests done.
>>>>>The test methods and the implementation and the conclusions are
>>>>>grammar school level.
>>>>>I do not know who proofread it, but it gotta be idiots or people who
>>>>>didn't care at all.
>>>>>Amazingly Bob defended Omid here and said nothing was wrong with
>>>>>the article.
>>>>Bob also found that verification search is good for crafty based on his post.
>>>>Bob is not the onlyone who defended Omid.
>>>>I also defend him and you are the only poster who attacks him(even posters who
>>>>said that it did not work for them did not say that it is very bad).
>>>>Most of what you say is not correct.
>>>You are dreaming.
>>>Ok to list a few bugs in his paper:
>>>  a) all his test positions are mates and he doesn't do
>>>     checks in qsearch so R=2 versus R=3 matters a lot because
>>>     of the extra ply you miss of the main search finding the
>>>     mate for you. So if your qsearch is so buggy it is logical
>>>     that R=2 works at depth==9 better than R=3 at depth==9,
>>>     this is *trivial*. It is so trivial that no serious researcher
>>>     should compare the same plydepths with each other without
>>>     taking into account time.
>>>     Because we are going to conclude that minimax search is better
>>>     than alfabeta for sure.
>>Alpha-Beta is a form of minimax.  Time is important, I don't know if he
>>considered it or not.
>>>  b) now already assuming the bug in his comparision is there to
>>>     compare depth==9 with depth==9 instead of the factor time,
>>>     then the bug is that he is just testing mates so reduction
>>>     factor matters. It is trivial to try adaptive nullmove then.
>>>  c) there is major bugs in the program Genesis looking at the
>>>     branching factor differences between R=1, R=2 and R=3.
>>>     I do not know a single serious chess program that has
>>>     such a difference.
>>Every chess program has a different branching factor.
>>>  d) Genesis needs way too much nodes to get to a decent plydepth
>>>     when compared to even programs doing checks in their qsearch
>>>     and extensions in nominal search. For mate in 2 he needs like
>>>     10 million nodes to get to depth == 10.
>>It isn't as good as some other programs, but that can be said of any program
>>that is not a WMCCC winner or SSDF winner.
>>>  e) illegal position in his testset.
>>It was corrected in the actual test.  He had a bad version posted on his web
>>>  f) his algorithm is not new. It is a rewrite of something already
>>>     existing and he rewrote it wrong. He has a bug in his verification
>>>     search. You can easily proof it by using transpositions.
>>Perhaps it is a rediscovery to some degree.  In any case, it was new to me.
>>>  g) It won't detect a zugzwang for sure simply because of transposition
>>>     bugs. Therefore the only claim can be that it is enhancing tactical
>>>     abilities of his program. Therefore it is crucial to also test
>>>     different forms of adaptive nullmove (with different depths to
>>>     go from R=3 to R=2).
>>I think this is untethered extrapolation.
>>>  h) It is unclear why he concluded verification search is better using
>>>     his own data.
>>>       a) more Fullwidth search than verification
>>>          clearly finds more positions.
>>>       b) R=3 uses less nodes than his verification search.
>>>     it is very unclear how he concludes then that verification search
>>>     is better. It's topping nowhere a list of 'this works better'.
>>>   i) Even from where i sit and without having genesis i can already smell
>>>      that adaptive nullmove works better than his own verification search.
>>>      his beloved verification search you can easily write down what it is
>>>      doing on paper. It's simply avoiding to nullmove last few plies
>>>      initially. So there is always a form of adaptive nullmove that is
>>>      going to completely outgun it simply.
>>Every chess program will have a different response to some new technique.
>>Perhaps his own program will behave in a totally different way if he changes his
>>move ordering.  In any case, it is an interesting idea and an interesting read
>>(for me)...  Obviously YMMV.
>>>   j) the testset is just basically mating positions in all tests.
>>>      that's a very dangerous ground to conclude things.
>>It is the only way to be 100% sure that the outcome is correct.  If you have any
>>position with only a material win, it is always possible that the move not only
>>is not the best move but also that may even lose.
>>>Note that at depth == 10 ply i solve with diep with R=3 i solve far more
>>>positions in way less nodes than this guy ever will. This testset is just
>>>too simple.
>>Why not write a truly excellent research paper and publish it?  Those that
>>bother to do it should be commended for their efforts.  We rarely see praise for
>>attempted explations of chess ideas and we often see ridicule.  Quite frankly, I
>>don't think that even the most basic of questions like "Bitboard or 0x88" or
>>"Fast/dumb verses Slow/smart evaluations" are answered.  Hence, any logical
>>debate on chess ideas is a good thing.  Some ideas may be a rehash of an old
>>notion or (perhaps) a slight tweak to an old idea.  But for some of us idiots,
>>it still makes for a bit of good and enjoyable reading.  And yet another thing
>>to try.
>I wanted to support this - as a lay. We should take care that the debate remains
>a debate on the topics itself and does not pervert into a discrimation of
>"beginners". I have no reason to defend Omid, but I still find it a bit strange
>by Vincent to show such a lack of patient understanding. To me he looks as if he
>were a beginner of some sort too and he's jealous of the tries Omid presented.
>This is all very sad. Why not simply showing some respect and supporting each
>other. To mention the beginners aspect is in itself nonsense. Because the
>details speak their own language. I'm astonished that Vincent can't show more
>openess as an established advanced programmer. It is as if he wanted to keep
>Omid out of it.
>Therefore it's riht to the point that you simply show what was new for you as
>experts. As far as I could understand the whole debate is even interesting for
>experts. So, that should be the point to be told to Omid.
>I'm surprised how premature Vincent could react on Omid who is not in Bob's
>legue yet! :)
>Please say what is absolutely wrong in all clearness but don't put Omid down,
>although, I'm sure, that he won't let himself kept away.
>All in all, I find such discussions very valuable. They should be invented if
>they didn't appear by chance. Everybody can learn something.

If it were Bruce Moreland making the same statements, I would be horrified by
them.  But not at all by Vincent.  You will find that Vincent will descibe his
own attempts at something as "shit" if they do not work out.  He sees only
excellence or worthlessness and very little territory between.

It's just Vincent being Vincent.  He could be more polite, but I suspect that
it's just the Higgins effect.

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