Author: Christophe Theron
Date: 18:54:44 01/25/00
Go up one level in this thread
On January 25, 2000 at 14:40:57, Jeremiah Penery wrote:
>On January 25, 2000 at 14:02:01, Christophe Theron wrote:
>
>>Actually many programs prove everyday that using an imperfect pruning scheme is
>>much better than no pruning at all. Yours included (I don't mean your pruning is
>>imperfect).
>>
>>I see no reason to believe that this would change just because you are be able
>>to compute 4, 5 or even 10 plies deeper.
>>
>>Is it really still debatable? It was maybe, 20 years ago, but now we all know
>>the answer...
>
><snip>
>
>>My main point is that not using a pruning scheme is somewhat... stup...
>>Ahem... not really optimal.
>
><snip>
>
>>But I'm sorry, not using any pruning scheme, if it is really what they did,
>>sounds like a "political" decision. I cannot believe that Hsu is stupid enough
>>to really believe that DB plays better without pruning.
>>
>>It is either a huge professional mistake or a deliberate public relations
>>choice. You guess.
>
><snip>
>
>>OK, he had all this power as a result of his very hard work. So he deserved it.
>>But the total package could have been much better with a pruning scheme. The
>>thing that has played against Kasparov was far from being finished.
>
>Even the best selective-search algorithm will sometimes cause you to play a
>different move than you would without it. You will 'miss something', so to
>speak. If you were writing a program to play against arguably the best chess
>player _ever_, would you want to risk this happening even once and losing
>because of it?
Of course I would implement a selective search.
It has been the main source of improvements in computer chess for the last 2
decades.
The drawbacks are very small when compared to the advantages.
This is clearly demonstrated by the success of microcomputer chess programs
since Psion chess in 1981. And even before.
> Especially if you had the speed not to really worry about it, as
>they did. Also, it may have been a matter of time. Since there was little time
>to do much testing, it would've been way too hard to write and debug a good
>selective search algorithm. They had other problems to worry about.
The lack of time is indeed the reason I think.
>In effect, they did do a bit of selective search, through their extensions. You
>could call their search a highly-selective 30-ply+ search. :) They just were
>not selective in the first part of the search.
It is a related idea, but it's not the same.
>I do agree that they may have been a bit better if they had some sort of
>selective search, however. I just don't think it was practical or really
>important for them to worry about.
Because they had no serious competition. Kasparov could have punished them, but
he failed too, unfortunately. Not that I think he is not able to. But on this
particular occasion, he failed.
Christophe
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