Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Checks in the Qsearch

Author: Robert Hyatt

Date: 14:19:21 07/06/02

Go up one level in this thread


On July 06, 2002 at 11:03:42, Uri Blass wrote:

>On July 06, 2002 at 10:25:44, Robert Hyatt wrote:
>
>>On July 06, 2002 at 01:28:07, Ricardo Gibert wrote:
>>
>>>
>>>When I read in CCC that the Deep Blue search had an EBF of about 4, my thoughts
>>>were, "Ugh! That means that in about 50 years of the expected hardware
>>>improvements, the PC programs of the day will be able to surpass Deep Blue even
>>>if Deep Blue were to get the commensurate hardware improvements."
>>
>>The problem is that you are making a _classic_ mistake.  The EBF has _nothing_
>>to do with how the two programs will compare.  What is important is the _tree_
>>that both search.  If one does a 20 ply search, and the other does a 10 ply
>>search, but they search the same tree, then they play equally tactically.
>>
>>Don't get hung up on a 20 ply search depth (iteration number).  It doesn't
>>mean a thing when compared to _other_ programs..
>>
>>
>>
>>>
>>>The big advantage in EBF of the then current programs is like a juggernaut that
>>>cannot be stopped. That I was not impressed with Deep Blue is an understatement.
>>>Deep Blue was superior...then, but this was *despite* its method of search. Its
>>>hardware made it superior and not its search methods.
>>
>>
>>Its search methods are far from primitive.  IE they have been doing singular
>>extensions since the late 1980's.  Others started to copy the idea much later.
>
>
>I am interested to know about a single programmer who copied the way that they
>used singular extensions.


OK...  first, me, in Cray Blitz.  1994.  GCP modified Crafty and used the
Hsu-definition of SE in doing so.  Hans Berliner did SE in Hitech.  Dave
Kittinger did the PV-singular implementation as defined by Hsu.  He did not
do the FH-singular part however, as it was too expensive for his tastes and
since he was using a micro, that might have been reasonable.  We know Genius
used this around version 2 or 3, although no details about how it was
implemented were ever published...



>There are programmers who use singular extensions but I know about no programmer
>of one of the top programs of today that use it in the way that they use it.


So?  They choose to implement a less-than-optimal version to control the
computational cost.  The DB guys didn't have to give much thought to the
computational cost at the speed they were searching.  Again, an apples-to-
oranges comparison when one side worries about speed while the other side
doesn't have to.





>
>If their ideas about singular extensions were so good how is it possible that
>nobody copied their algorithm succesfully until today and even people who use
>singular extensions(bruce moreland) use inferior algorithm if we believe you
>about it.
>


Several _have_ copied it.   I gave you several names above.


>Is their algorithm about singular extensions a secret?
>


How could it be when it was published in the JICCA several years
ago, in full detail?





>Uri



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.