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Subject: Re: Problem with Rybka 1.01 ??

Author: Barry Culp

Date: 14:55:57 12/22/05

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On December 22, 2005 at 17:29:04, Vasik Rajlich wrote:

>On December 22, 2005 at 13:28:48, Barry Culp wrote:
>
>>I just got my copy of Rybka 1.01 and the first position I tried to
>>analyze has a possible problem ? I am using the Fritz 9 GUI on a
>>P4 3.6 ghz with 512mb hash in infinite analysis mode.
>>
>>The older version Rybka 1.0 switches from  Rh5 (-4.11) to Ke2 (-.80) in 7:16
>>at ply 15.
>>
>>The newer version Rybka 1.01 stays on Rh5 ply 13 and doesnt make
>>any more progress after 30 minutes ??? I was able to reproduce
>>this "problem" a second time. I even tried booting my PC after each analysis.
>>
>>Can anyone with Rybka 1.01 reproduce my results ??
>>
>>
>>[D] r6k/6p1/pq1pB1Pp/2nP1R2/2Q2p2/P1R2P2/2PK3P/1r6 w - - 0 1
>>
>>
>>Analysis by Rybka 1.0 Preview 32-bit:
>>
>>34.Rh5 Nxe6 35.dxe6 Re8 36.Rb3 Qf2+ 37.Qe2 Qxe2+ 38.Kxe2 Rg1 39.Kd3 Rxg6
>>  ³  (-0.30)   Depth: 11   00:00:13  687kN
>>34.Rh5 Nxe6 35.dxe6 Re8 36.Rb3 Qf2+ 37.Qe2 Qxe2+ 38.Kxe2 Rg1 39.Kd3 Rxg6 40.Rf5
>>  ³  (-0.33)   Depth: 12   00:00:25  1354kN
>>34.Rh5 Nxe6 35.dxe6 Re8 36.Rb3 Qf2+ 37.Qe2 Qxe2+ 38.Kxe2 Rg1 39.Kd3 Rxg6 40.Rf5
>>Rgxe6
>>  ³  (-0.33)   Depth: 13   00:00:46  2558kN
>>34.Rh5 Nxe6 35.dxe6 Re8 36.Rf5 Qg1 37.Qe2 Qxg6 38.Rxf4 Rxe6 39.Rc8+ Kh7 40.Qd3
>>  ³  (-0.48)   Depth: 14   00:01:29  5272kN
>>34.Rh5 Nxe6 35.dxe6 Qf2+ 36.Qe2 Qd4+ 37.Rd3 Qg1 38.Rc3 Rf1 39.Ra5 Rf2 40.Rxa6
>>Rxe2+
>>  -+  (-4.11)   Depth: 15   00:04:10  14311kN
>>34.Ke2 Re8 35.Qxf4 Nxe6 36.dxe6 Rxe6+ 37.Kd2 Qf2+ 38.Kd3 Qe2+ 39.Kd4 Rd1+ 40.Rd3
>>Rxd3+
>>  µ  (-0.80)   Depth: 15   00:07:16  23074kN
>>
>>
>>Analysis by Rybka 1.01 Preview 2 32-bit:
>>
>>34.Rh5 Nxe6 35.dxe6 Re8 36.Rb3 Rxb3 37.cxb3 Qe3+ 38.Kc2 Rxe6 39.Qc8+ Re8 40.Qb7
>>  ³  (-0.41)   Depth: 11   00:00:11  1588kN
>>34.Rh5 Nxe6 35.dxe6 Re8 36.Rb3 Qf2+ 37.Qe2 Qxe2+ 38.Kxe2 Rg1 39.Rf5 Rxg6 40.Rxf4
>>  ³  (-0.33)   Depth: 12   00:00:24  3348kN
>>34.Rh5 Nxe6 35.dxe6 Re8 36.Rb3 Qf2+ 37.Qe2 Qxe2+ 38.Kxe2 Rg1 39.Rf5 Rxg6 40.Rxf4
>>Rgxe6+
>>  ³  (-0.40)   Depth: 13   00:00:45  6395kN
>>
>>No further analysis here after 30 minutes ?? Notice the difference
>>in node count on plys 11-13 between the 2 versions
>
>This has a very simple technical explanation.
>
>Rybka 1.0 Beta never resolved mates - all mates were equal.
>
>Rybka 1.01 Preview 2 resolves mates under the following two scenarios:
>1) Infinite analysis mode
>2) When it's time to go mate the opponent (ie. previous search was mating)
>
>Currently, Rybka resolves mates very inefficiently. There are a number of
>solutions, I will improve it in time for Rybka 1.2. For now, Rybka can take a
>long time to resolve the mate.
>
>Please note that this is relevant even though Rh5 doesn't get completely mated.
>It's obvious there are a lot of mating variations there.
>
>As for Aaron's finding - "go depth 999" is not considered infinite analysis
>mode, so mates are not resolved there.
>
>Vas

Thanks Vas

I went back to Fritz 9 GUI and instead of using infinite analysis I tried
Game/Levels/Fixed Time and set it to 50.

Wala ! Rybka 1.01 finds 34. Ke2 in a few minutes



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