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Subject: Re: Rybka's oddity! Can anyone reproduce this......?

Author: Uri Blass

Date: 15:01:41 02/02/06

Go up one level in this thread


On February 02, 2006 at 17:52:20, Uri Blass wrote:

>On February 02, 2006 at 17:44:30, Uri Blass wrote:
>
>>On February 02, 2006 at 16:07:20, George Tsavdaris wrote:
>>
>>> I noticed a strange behaviour and definitely a bad one from latest Rybka, and
>>>for Winfinder so that means it should be a general bad behaviour of Rybka
>>>family:-)  Possible bug that prevents correct analysis.....
>>>
>>> This behaviour is noticed at Fritz 8 GUI(i haven't tried Arena yet). It is also
>>>happening at Deep Fritz 8 GUI. It must be a hashproblem or something.....
>>> Conditions(I'll describe the procedure i followed--Keep in mind that the values
>>>for the seconds i've made analysing between the moves should not play any role
>>>at all and different values would produce the problem again):
>>>
>>>Set the following game:
>>>
>>>[Event "??"]
>>>[Site ""]
>>>[Date "2005.01.03"]
>>>[Round "?"]
>>>[White "Tsavdaris"]
>>>[Black "????"]
>>>[Result "1-0"]
>>>[PlyCount "54"]
>>>[EventDate "2005.??.??"]
>>>
>>>1. e4 e5 2. f4 d5 3. exd5 exf4 4. Nf3 Nf6 5. c4 c6 6. Nc3 cxd5 7. d4 Bb4 8. Be2
>>>Ne4 9. O-O Bxc3 10. bxc3 Nxc3 11. Qc2 Nxe2+ 12. Qxe2+ Be6 13. Ba3 dxc4 14. d5
>>>Qxd5 15. Rad1 Qb5 16. Nd4 Qb6 17. Kh1 Nd7 18. Rxf4 O-O-O 19. Nxe6 Qxe6 20.
>>>Rxc4+ Kb8 21. Qxe6 fxe6 22. Rcd4 b5 23. Rxd7 Rxd7 24. Rxd7 Rc8 25. Bd6+ Ka8 26.
>>>Bc7 a6 27. Rxg7 Rf8 1-0
>>>
>>>-Set Rybka as an engine, clear hashtables and set it to let's say 256 MB.
>>>-Go to move 14 for black and start analysis with Rybka(multivariation with 4
>>>lines i had) for some seconds(4-5).
>>>-It displays the move Rad1 as best. Press the "Right Key" button from the
>>>keyboard in order the next move to be executed while the analysis will continue.
>>>-Press the "Right Key" button again after 1-2 seconds so the move Qb5 will be
>>>played.
>>>-Press the "Right Key" button again after 4-5 seconds so the move Nd4 will be
>>>played.
>>>-Press the "Right Key" button again after 1-2 seconds.
>>>Now Rybka displays 17.Rxf4 as the best move with -2.00 evaluation!
>>>So what? Well if we clear at that point the hashtables then Rybka displays the
>>>correct evaluation and correct move which is 17.Kh1 with a positive score.
>>>
>>> Also if we put the position with white at move 17 to play, to Rybka to analyse
>>>then we get the correct analysis. But if we have the analysis open from move 15
>>>and continue up to move 17 for white we get 17.Rxf4????
>>>
>>>
>>>Can anyone reproduce this.....?
>>
>>I could reproduce it in 3 option mode
>>
>>Here is the pv at depth 14
>>
>>Tsavdaris,  2005
>>rn2k2r/pp3ppp/1q2b3/8/2pN1p2/B7/P3Q1PP/3R1RK1 w kq - 0 1
>>
>>Analysis by Rybka 1.01 Beta 13b 32-bit:
>>
>>1. -+  (-2.38): 17.Rxf4
>>2. -+  (-2.38): 17.Kh1
>>3. -+  (-2.53): 17.Bb2
>>
>>(,  03.02.2006)
>>
>>depth 15:
>>
>>Tsavdaris,  2005
>>rn2k2r/pp3ppp/1q2b3/8/2pN1p2/B7/P3Q1PP/3R1RK1 w kq - 0 1
>>
>>Analysis by Rybka 1.01 Beta 13b 32-bit:
>>
>>1. -+  (-2.44): 17.Rxf4
>>2. -+  (-2.44): 17.Kh1
>>3. -+  (-2.59): 17.Bb2
>>
>>(,  03.02.2006)
>>
>>one of the strenge things is that there is no pv for none of the lines
>>
>>Uri
>
>A simpler way to reproduce it is to start from the position after 15.Rad1 and
>make the game moves 15...Qa5 16.Nd4 Qb6 fast.
>
>I get the following analysis at depth 14:
>
>Tsavdaris,  2005
>rn2k2r/pp3ppp/1q2b3/8/2pN1p2/B7/P3Q1PP/3R1RK1 w kq - 0 1
>
>Analysis by Rybka 1.01 Beta 13b 32-bit:
>
>1. -+  (-2.44): 17.Bb2
>2. -+  (-2.45): 17.Rxf4
>3. -+  (-2.45): 17.Kh1
>
>(,  03.02.2006)
>
>
>
>
>Uri

I tried to reproduce it under shredder gui

Here is what I get
As you can see Rybka cannot see Kh1 with a positive score in a reasonable time.

I gave up at depth 16

CPU0: AuthenticAMD x86 Family 15 Model 4 Stepping 8 2009 MHz
GUI: Tablebases with 5 pieces found! [Cache: 16 MB + internal 13.67 MB]
Engine: Rybka 1.01 Beta 13b 32-bit (256 MB)
by Vasik Rajlich
best move: Qd5-b5 time: 0:00.234 minnodes: 72
-----
  8	 0:00 	+1.42 	15...Qa5 16.Nd4 Qb6 17.Rxf4 O-O-O (37.932) 45
  8	 0:01 	+0.47 	15...Qb5 16.Ne5 Nc6 17.Nxf7 Kxf7 18.Rxf4+ Bf5 (64.828) 43
  7	 0:00 	 0.00 	15...Qf5 16.Qb2 Nd7 17.Rxd7 (26.202) 42
-----
  8	 0:00 	+1.42 	15...Qa5 16.Nd4 Qb6 17.Rxf4 O-O-O (37.932) 45
  8	 0:01 	+0.47 	15...Qb5 16.Ne5 Nc6 17.Nxf7 Kxf7 18.Rxf4+ Bf5 (64.828) 43
  8	 0:01 	-1.63 	15...Qf5 16.Qb2 Nd7 17.Rxd7 Bxd7 18.Qxb7 (73.424) 44
-----
  8	 0:00 	+1.42 	15...Qa5 16.Nd4 Qb6 17.Rxf4 O-O-O (37.932) 45
  8	 0:01 	+0.47 	15...Qb5 16.Ne5 Nc6 17.Nxf7 Kxf7 18.Rxf4+ Bf5 (64.828) 43
  8	 0:01 	-0.64 	15...Qc6 16.Rd6 Qc8 17.Ng5 O-O (79.820) 43
best move: Qd5-a5 time: 0:01.875 min  n/s: 44.717  nodes: 81.924
-----
  8	 0:01 	-0.32 	16.Ne5 Nc6 17.Nxf7 Kxf7 18.Rxf4+ Bf5 19.Rd7+ Kg8 (68.426) 53
  8	 0:02 	-1.16 	16.Qd2 Qb6+ 17.Rf2 Nd7 18.Qxf4 O-O-O (105.017) 53
  8	 0:01 	-1.64 	16.Nd4 Qb6 17.Rxf4 O-O-O 18.Kh1 (73.063) 51
best move: Nf3-e5 time: 0:02.422 min  n/s: 52.279  nodes: 122.887
-----
  9	 0:01 	+1.71 	16...Qb6 17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qc2 (78.673) 47
  8	 0:01 	-4.40 	16...Qa6 17.Nxe6 fxe6 18.Rd6 Qxd6 19.Bxd6 Kd7 (53.269) 46
  8	 0:01 	-4.56 	16...Qd5 17.Nxe6 Qxe6 18.Rfe1 Nc6 19.Qh5 (54.604) 46
best move: Qb5-b6 time: 0:01.782 min  n/s: 47.051  nodes: 81.927
-----
  9	 0:01 	-2.10 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Re4 Qa6 (62.284) 52
  9	 0:01 	-2.10 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Re4 Qa6 (72.312) 54
  9	 0:01 	-2.39 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kh1 Rhe8 (97.020) 53
-----
 10	 0:03 	-2.05 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qc2 g5 20.Re4 (164.900) 52
  9	 0:01 	-2.10 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Re4 Qa6 (72.312) 54
  9	 0:01 	-2.39 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kh1 Rhe8 (97.020) 53
-----
 10	 0:03 	-2.05 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qc2 g5 20.Re4 (164.900) 52
 10	 0:03 	-2.05 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qc2 g5 20.Re4 (183.013) 53
  9	 0:01 	-2.39 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kh1 Rhe8 (97.020) 53
-----
 10	 0:03 	-2.05 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qc2 g5 20.Re4 (164.900) 52
 10	 0:03 	-2.05 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qc2 g5 20.Re4 (183.013) 53
 10	 0:04 	-2.54 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kh1 Rd5 20.Qd2 (220.827) 53
-----
 11	 0:07 	-2.09 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qc2 g5 20.Rb1 Qa6 (368.606) 52
 10	 0:03 	-2.05 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qc2 g5 20.Re4 (183.013) 53
 10	 0:04 	-2.54 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kh1 Rd5 20.Qd2 (220.827) 53
-----
 11	 0:07 	-2.09 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qc2 g5 20.Rb1 Qa6 (368.606) 52
 11	 0:07 	-2.09 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qc2 g5 20.Rb1 Qa6 (406.871) 53
 10	 0:04 	-2.54 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kh1 Rd5 20.Qd2 (220.827) 53
-----
 11	 0:07 	-2.09 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qc2 g5 20.Rb1 Qa6 (368.606) 52
 11	 0:07 	-2.09 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qc2 g5 20.Rb1 Qa6 (406.871) 53
 11	 0:09 	-2.49 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kf1 Rhe8 20.Bc3 Nxd4 (495.440) 54
-----
 12	 0:19 	-2.40 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.h4 Qa5 20.Qb2 Na6 21.Kh2
(984.848) 52
 11	 0:07 	-2.09 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qc2 g5 20.Rb1 Qa6 (406.871) 53
 11	 0:09 	-2.49 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kf1 Rhe8 20.Bc3 Nxd4 (495.440) 54
-----
 12	 0:19 	-2.40 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.h4 Qa5 20.Qb2 Na6 21.Kh2
(984.848) 52
 12	 0:20 	-2.40 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.h4 Qa5 20.Qb2 Na6 21.Kh2
(1.073.358) 52
 11	 0:09 	-2.49 	17.Bb2 O-O-O 18.Rxf4 Nc6 19.Kf1 Rhe8 20.Bc3 Nxd4 (495.440) 54
-----
 12	 0:19 	-2.40 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.h4 Qa5 20.Qb2 Na6 21.Kh2
(984.848) 52
 12	 0:20 	-2.40 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.h4 Qa5 20.Qb2 Na6 21.Kh2
(1.073.358) 52
 12	 0:25 	-2.47 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Nxd4 20.Bxd4 Qd6 21.Bxg7 Qxd1
(1.354.419) 54
-----
 13	 0:39 	-2.42 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.h3 g5 20.Re4 Nc6 21.Nxe6 Rxd1+
22.Qxd1 Rxe6 (2.042.860) 52
 12	 0:20 	-2.40 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.h4 Qa5 20.Qb2 Na6 21.Kh2
(1.073.358) 52
 12	 0:25 	-2.47 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Nxd4 20.Bxd4 Qd6 21.Bxg7 Qxd1
(1.354.419) 54
-----
 13	 0:39 	-2.42 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.h3 g5 20.Re4 Nc6 21.Nxe6 Rxd1+
22.Qxd1 Rxe6 (2.042.860) 52
 13	 0:41 	-2.42 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.h3 g5 20.Re4 Nc6 21.Nxe6 Rxd1+
22.Qxd1 Rxe6 (2.182.164) 53
 12	 0:25 	-2.47 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Nxd4 20.Bxd4 Qd6 21.Bxg7 Qxd1
(1.354.419) 54
-----
 13	 0:39 	-2.42 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.h3 g5 20.Re4 Nc6 21.Nxe6 Rxd1+
22.Qxd1 Rxe6 (2.042.860) 52
 13	 0:41 	-2.42 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.h3 g5 20.Re4 Nc6 21.Nxe6 Rxd1+
22.Qxd1 Rxe6 (2.182.164) 53
 13	 0:45 	-2.53 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Nxd4 20.Bxd4 Qd6 21.Bxg7 Qxd1
22.Qc5+ Kb8 (2.472.325) 55
-----
 14	 1:13 	-2.45 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 (3.777.025) 52
 13	 0:41 	-2.42 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.h3 g5 20.Re4 Nc6 21.Nxe6 Rxd1+
22.Qxd1 Rxe6 (2.182.164) 53
 13	 0:45 	-2.53 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Nxd4 20.Bxd4 Qd6 21.Bxg7 Qxd1
22.Qc5+ Kb8 (2.472.325) 55
-----
 14	 1:13 	-2.45 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 (3.777.025) 52
 14	 1:17 	-2.45 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 (4.050.143) 53
 13	 0:45 	-2.53 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Nxd4 20.Bxd4 Qd6 21.Bxg7 Qxd1
22.Qc5+ Kb8 (2.472.325) 55
-----
 14	 1:13 	-2.45 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 (3.777.025) 52
 14	 1:17 	-2.45 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 (4.050.143) 53
 14	 1:29 	-2.47 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Rxd4 20.Bxd4 Nxd4 21.Rxd4 g5
22.Rfd1 h5 23.g3 Rg8 (4.817.805) 55
-----
 15	 2:07 	-2.53 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 (6.986.426) 56
 14	 1:17 	-2.45 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 (4.050.143) 53
 14	 1:29 	-2.47 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Rxd4 20.Bxd4 Nxd4 21.Rxd4 g5
22.Rfd1 h5 23.g3 Rg8 (4.817.805) 55
-----
 15	 2:07 	-2.53 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 (6.986.426) 56
 15	 2:19 	-2.53 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 (7.780.652) 57
 14	 1:29 	-2.47 	17.Bb2 O-O-O 18.Bc3 Nc6 19.Qf2 Rxd4 20.Bxd4 Nxd4 21.Rxd4 g5
22.Rfd1 h5 23.g3 Rg8 (4.817.805) 55
-----
 15	 2:07 	-2.53 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 (6.986.426) 56
 15	 2:19 	-2.53 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 (7.780.652) 57
 15	 3:04 	-2.58 	17.Bb2 O-O-O 18.Kh1 Rhe8 19.Bc3 Qc7 20.Nxe6 Rxd1 21.Rxd1 Rxe6
22.Qh5 g6 23.Qxh7 (10.449.420) 58
-----
 16	 4:41 	-2.53 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 23.Rf6 (16.003.574) 58
 15	 2:19 	-2.53 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 (7.780.652) 57
 15	 3:04 	-2.58 	17.Bb2 O-O-O 18.Kh1 Rhe8 19.Bc3 Qc7 20.Nxe6 Rxd1 21.Rxd1 Rxe6
22.Qh5 g6 23.Qxh7 (10.449.420) 58
-----
 16	 4:41 	-2.53 	17.Rxf4 O-O-O 18.Kh1 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 23.Rf6 (16.003.574) 58
 16	 4:55 	-2.53 	17.Kh1 O-O-O 18.Rxf4 Rhe8 19.Qf1 Qa6 20.Bb2 Bd5 21.Rf2 g6
22.a3 Nc6 23.Rf6 (16.984.246) 58
 15	 3:04 	-2.58 	17.Bb2 O-O-O 18.Kh1 Rhe8 19.Bc3 Qc7 20.Nxe6 Rxd1 21.Rxd1 Rxe6
22.Qh5 g6 23.Qxh7 (10.449.420) 58



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