Author: Vincent Diepeveen
Date: 16:37:09 10/19/02
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On October 19, 2002 at 17:39:50, Mark Young wrote: fritz is a bad example to compare with. Take for example diep or other engines doing loads of checks in qsearch and no forward pruning. deep blue forward pruned in hardware last 3 ply. for testsets if i forward prune last 3 ply i do not notice problems either. we know deep blue was hardly tested. Jan Louwman played earlier this year about several hundreds of testgames when i had a version forward pruning last 3 ply. It was scoring 20% less than the version not forward pruning. the 3 ply forward pruning version was searching on average (also by not using dangerous extensions) 2 ply deeper. My conclusion was that forward pruning positional lines is very dubious. >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 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 > >I also think you are correct that a brute force 12 ply search is not better then >a 14 ply Deep fritz search. I think this is supported by the Kramnik match >results, and why Kramnik said he found Deep Fritz playing better moves in the >same position as Deep Blue. I don't think Kramnik was blowing smoke when he said >Deep Fritz is stronger then Deep Blue.
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