Author: Vincent Diepeveen
Date: 19:15:20 10/25/02
Go up one level in this thread
On October 25, 2002 at 16:17:30, Bob Durrett wrote: >On October 19, 2002 at 17:27:43, Uri Blass wrote: > >>On October 19, 2002 at 17:03:51, Dave Gomboc wrote: >> >>>On October 19, 2002 at 14:45:19, Steve Lim wrote: >>> >>>>SJLIM: Alot of programmers on CCC have asked me to ask you this.. for >>>>clarification.. >>>>SJLIM: Please explain search depths for the notations 4(5) and clarify earlier >>>>comments about 12(6). This may include indicating what is "normal full width" >>>>searching, extensions, quiesence search, or other types of searching DB2 >>>>utilized, and which was done in software versus in the hardware chess chips. >>>>SJLIM: Also, what types of pruning were used. This topic has generated enourmous >>>>discussion on CCC. >>>>CrazyBird: 4(5)means the same thing. 5-ply maximum hardware depth, although it >>>>is obviously impossible in this case. >>>>CrazyBird: since the brute force depth is 4. >>>>CrazyBird: i can't really go into the details of the hardware pruning. it is >>>>related to method of analogy pruning, or rather a basterized form of it. >>>>CrazyBird: limitation in the contract with ibm. >>>>SJLIM: Can this be answered? - Does 12(6) mean the 6 is included _in_ the 12, or >>>>in addition to the 12? >>>>CrazyBird: 6 is part of 12, but the hardware can search less than 6, that is the >>>>software horizon may be more than 6 plies. >>>>CrazyBird: and of course, the selective depth can be arbitrarily deep, well, no >>>>more than 8 times brute force. >>>>CrazyBird: argh, the q search. it is in hardware. both sides are allowed checks >>>>in quiescence search. max is 8, i think. >>> >>>Clearly, Vincent's interpretation is supported here. >>> >>>I'm still sure they were searching much deeper than 12 ply in important lines >>>though! >>> >>>Dave >> >>Of course and it is the case for every program. >> >>They probably searched more important lines >Please overlook my lack of experience in search algorithms, but I would like to >know if the modern day search algorithms somehow home in on "important lines" >and avoid "less important lines"? The root cause of my confusion here is that I >don't know the definition of the word "important" as itis used in this context. Yes the nullmove enhancement is used for this. It is the most powerful form of pruning ever invented and is applyable to any game playing search algorithm. It is so powerful that the branching factor of my GO software even has gotten an acceptible branching factor (under 10.0). It is not so amazing however that an algorithm that is so simple working seemingly, that it took years for everyone to understand how correct the recursive form of it is, from minimax viewpoint seen. Of course in a weird game like draughts it is not possible to use such an algorithm, but that's one of the few humble exceptions to the rule. In general standing still means no progress. And that's the worst move that anyone can make. Military software can definitely learn a lot from computerchess. >Bob D. > > > >>than Fritz so I do not think that >>their 12 plies are eqvivalent to fritz's 12 plies but I still strongly believe >>that their 12 plies are not more than Fritz's 14 plies and Fritz can search more >>than 14 plies in the middle game with fast hardware so I guess that Fritz with >>fast hardware is better. >> >>Uri
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