Author: Vincent Diepeveen
Date: 08:04:18 01/30/02
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On January 30, 2002 at 10:12:25, Gian-Carlo Pascutto wrote: >Why are you blindly assuming that their effective branching factor >is 40, just because that is the average number of legal chess >moves? You should know better. And I know you do. branching factor is not the issue here GCP and you know it. the total number of nodes needed when assuming a theoretical minimum here is more important. Please get your college book again and see that this is about the squareroot of the number of legal moves. The average number of legal moves, not counting checking positions as those get extended, it is 40. so squareroot(40) is what you need for nodes. >They used PVS. Aspiration windows. Hashtables for the first TWELVE >plies. Even futility pruning. In 1998 and 1999 it was mentionned by direct postings from Hsu and others that they only did a fullwidth search not a single form of pruning as they disbelieved this, Bob has quoted that zillions of times in these years. Now in 2002 to explain some theoretical impossibilities a pruning technique for QUIESCENCESEARCH is getting quoted, don't confuse that with the alfabeta search. >I tested this. I crippled my program. No hashing in the last 6 plies, >no nullmove, no pruning except futility, all extensions on. >I didn't get an effective branching factor of 40. Far from it. >The _worst_ I saw was around 20, on _average_ it was only about 10 or >even less. that would make it 18^20 then in your case = 9^400, where i used 18^squareroot(40) = 9^40, get the point? >Now, let me do your math again. > >If I take the pessimistic value of 15, I get > >15^9 = 38443359375 nodes No they claim 12(6) is 18 ply. that means 18^squareroot(40) = 9^40 get the math? >At 200 000 000 nodes per second > >38443359375 / 200 000 000 = 192 seconds > >3 and a half minutes > >-- >GCP
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