Author: Uri Blass
Date: 16:24:39 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. > >Bob D. Search algorithms have extensions rules and pruning rules. programs extend the lines that they cosider as important to extend and prune lines that they consider as not important. Programs usually cosider checks as important so lines that include checks are searched for bigger depth and programs have more extension rules. Uri
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