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Subject: Re: Node speed

Author: Bas Hamstra

Date: 16:41:39 08/17/99

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Bob,

Double NPS <hijg> ? Could you explain lazy eval a bit more? Doing only material
eval to get Beta cutoffs or something? What about big positional scores? I saw
Ed Schroeder describe it as very dangerous, once...?


Regards,
Bas Hamstra.




On August 16, 1999 at 15:50:00, Robert Hyatt wrote:

>On August 16, 1999 at 07:54:28, Phil Dixon wrote:
>
>>
>>
>>
>>
>>Halwick Jr,F (2430) - Dikmen,A (2207) [B12]
>>corr M.040 IECG, 1998
>>
>>1.e4 c6 2.d4 d5 3.e5 Bf5 4.Nc3 e6 5.g4 Bg6 6.Nge2 c5 7.h4 h6 8.Be3 Qb6 9.f4 Nc6
>>10.f5 Bh7 11.Qd2 0-0-0 12.0-0-0 c4 13.Nf4 Qa6 14.fxe6 Nb4 15.exf7 Ne7 16.g5 Bxc2
>>17.Bh3+ Kb8 18.Rde1 Bh7 19.a3 Ng6 20.gxh6 gxh6 21.e6 Nxh4 22.Qf2 Be7 23.Qg3 Ka8
>>24.Kd1 Nd3 25.Nfxd5 Rxd5 26.Nxd5 Nxb2+ 27.Ke2 c3+ 28.Kf2 Nd3+ 29.Kg1 Qd6 30.Qxd6
>>Bxd6 31.Rf1 1-0
>>
>>While looking at this game with Fritz, I noticed the node speed hit 500k on move
>>9... and 1,500k on move 10... and 1,200k on move 11. Qd2.  Only very briefly,
>>1-2 seconds and at low ply levels.  I am wondering if this is a rather common
>>occurrence at low plys or if it has something to do with the position?
>>
>>I am running a 233 Mhz with 64 Megs of RAM.
>
>
>The best possible node speed comes when move ordering is bad.  IE Fritz seems
>to depend on the hash table for this, and at the start of a new position search,
>it has no idea... (IE I doubt it uses history ordering, etc, although I have no
>idea).  As the hash table gets useful stuff in it, the nps will drop.
>
>Another place is in wild positions where 'lazy evaluation' becomes very
>effective (ie in most variations lots of material has been won or lost,
>which makes lazy eval take almost zero time and can easily double the nps
>[at least in crafty])
>
>Bob



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