Author: Christophe Theron
Date: 20:59:59 06/30/02
Go up one level in this thread
On June 30, 2002 at 12:28:32, Robert Hyatt wrote:
>On June 29, 2002 at 14:18:53, Christophe Theron wrote:
>
>>On June 28, 2002 at 17:54:56, Keith Evans wrote:
>>
>>>On June 28, 2002 at 16:33:10, Scott Gasch wrote:
>>>
>>>>Another idea that I read from was that generating non-capturing checks in the
>>>>qsearch against a side that has had a chance to stand pat already is a waste. I
>>>>really don't understand this idea and disagree with it. Imagine black has had
>>>>an oppertunity to stand pat but instead plays RxN (N appears hung). Well this
>>>>looks really good unless white then generates Qd4+ forking blacks R and K and
>>>>winning the R. If you neglect to generate checks on a side who has already had
>>>>the chance to stand pat you let him get away with RxN and like it. If the only
>>>>reason to add checks to the qsearch is to find mates then I agree -- checking
>>>>after a side could stand pat is wasted. But if the goal is to improve tactical
>>>>play then I think this idea is not sound.
>>>
>>>I'll be very interested to see what responses this generates. Hsu took the time
>>>to design and implement special logic to help generate checking and check
>>>evasion moves in Deep Blue which I assume was used in qsearch. This was not a
>>>trivial undertaking - it adds both additional logic and additional interconnect.
>>>He probably had a good reason for doing it, since he could have used that time
>>>for something else like implementing a small hash table.
>>
>>
>>
>>And maybe he had no good reason to do it.
>>
>>As far as I know there are many amateur programmers here that have spent much
>>more time in trying and validating ideas (not even speaking of the commercial
>>programmers) than Hsu.
>>
>>I think Hsu and his team have done a great job in implementing a chess program
>>in a chip.
>>
>>However I think taking him and his team as a reference in chess programming is a
>>big mistake.
>>
>>As I have said, I think there are many chess programmers here who are much more
>>skilled than Hsu and his team in chess programming.
>>
>>
>>
>> Christophe
>>
>>
>
>
>Hmmm.. I would _never_ make that statement. Have you _ever_ talked with
>Hsu or Campbell? I suspect not because if you had, you would not think
>them quite that incapable.
I did not say that they are incapable. They have done things I will never be
able to do.
However I have read their description of the Deep genealogy (the document
published last year and describing their creatures in details, in particular
their evaluation function and search algorithms).
I think it's probably as good as or even better than having a talk with them, or
else what is the purpose of their publication?
Their evaluation function is quite complete but far from impressive (nothing
that a good micro program doesn't do - at least nothing important).
The job they have done on search is on the other hand poor in my opinion.
Poor is an understatement. Given the money they have been given for the project,
the almost total lack of work on the search algorithms is a shame.
If they knew as much as many amateur programmers nowadays, they would have
worked harder on the search. It is obvious that more work on this would have
given much, much better results.
The problem is that they have started their project with the level of knowledge
about search algorithms that was up to date at the time of Chess 4.8.
They have invested almost no work on search before starting to design the chips.
And since they have not invested much time on this either when they were working
on revisions of the chips, in the end they have got chips able to do the kind of
search that was great... back in the seventies.
Their chips do a brute force search, with a few exotic (most probably
inefficient) extensions.
Since nearly twenty years we know that brute search is vastly inferior to a good
selective search.
They have done a great achievement with a technique that is known to be vastly
inferior.
That leaves a bitter taste of what could have been achieved with the same
resources if they only had somebody capable enough (read: averagely skilled by
CCC's standards) on the subject of chess tree searching in their team.
Christophe, writing this under... Linux!!! :-)
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