Author: Albert Silver
Date: 13:27:12 01/06/06
Go up one level in this thread
>>>Your title is misleading so I changed it in my reply.
>>>My opinion is that Rybka searches x+2 plies when it claims to search x plies.
>>>
>>>From my experience it can see at fixed depth of 1 ply things that other programs
>>>see at fixed depth of 3 plies
Hiarcs sees it in 2 plies, and Chess Tiger 15 sees it in 1.
>>>Here is an example
>>>
>>>[D]3k2r1/ppb5/3p4/r2N1p2/8/8/1P6/1K2RB1R b - - 0 1
Analysis by Hiarcs 7.32:
1...Rxd5
-+ (-3.62) Depth: 1 00:00:00
1...Rxd5 2.Bc4
-+ (-3.29) Depth: 2/4 00:00:00
1...Rxd5 2.Bc4 Ba5 3.Bxd5 Bxe1 4.Bxg8
+- (2.07) Depth: 2/5 00:00:00
1...a6 2.Bc4
± (0.74) Depth: 2/7 00:00:00
1...Rf8 2.Bc4
² (0.67) Depth: 2/11 00:00:00
1...Bb6 2.Nxb6 axb6
² (0.55) Depth: 2/11 00:00:00
Analysis by Chess Tiger 15.0:
1...Rxd5
² (0.30) Depth: 1 00:00:00
1...Rxd5
-+ (-3.12) Depth: 1 00:00:00
1...Rxd5
+- (2.74) Depth: 1 00:00:00
1...f4 2.Nxf4
+- (1.80) Depth: 1 00:00:00
1...Rg3
± (1.14) Depth: 1 00:00:00
1...Rc5
± (1.10) Depth: 1 00:00:00
1...Rc5 2.Nf6
± (0.92) Depth: 2 00:00:00
1...Rc5 2.Nf4 Re5
± (1.08) Depth: 3 00:00:00 1kN
(Silver, Private 06.01.2006)
[D]3k2r1/pp1b4/3p4/r2N1p2/8/8/1P6/1K2RB1R b - - 0 1
Analysis by Hiarcs 7.32:
1...Rxd5
-+ (-3.79) Depth: 1 00:00:00
1...Rxd5 2.Bc4
-+ (-3.45) Depth: 2/4 00:00:00
1...Rxd5 2.Bc4 Bc6 3.Bxd5 Bxd5
-+ (-2.07) Depth: 2/5 00:00:00
1...Rxd5 2.Bc4 Bc6 3.Bxd5 Bxd5
-+ (-2.07) Depth: 3/10 00:00:00
Analysis by Chess Tiger 15.0:
1...Rxd5
² (0.32) Depth: 1 00:00:00
1...Rxd5
-+ (-3.04) Depth: 1 00:00:00
1...Rxd5
µ (-0.94) Depth: 1 00:00:00
1...Rxd5 2.Bc4
µ (-0.94) Depth: 2 00:00:00
1...Rxd5 2.Bc4 Bc6 3.Bxd5 Bxd5
µ (-0.94) Depth: 3 00:00:00
1...Rxd5 2.Bc4 Bc6 3.Bxd5 Bxd5
µ (-0.94) Depth: 4 00:00:00
1...Rxd5 2.Bc4 Bc6 3.Bxd5 Bxd5
µ (-0.94) Depth: 5 00:00:00 1kN
1...Rxd5 2.Bc4 Bc6 3.Rh6 Kd7 4.Rh7+ Kd8 5.Bxd5 Bxd5
³ (-0.52) Depth: 6 00:00:00 2kN
Albert
>>>
>>>Rybka does not capture the knight at depth 1 in the first case but capture the
>>>knight ar depth 1 in the second case.
>>>
>>>Can Vasik explain why?
>>>
>>>evaluation?
>>>I do not believe it.
>>>
>>>It must be search and rybka search after Rxd5 Bc4 black move and see that in the
>>>first case no move save black from a loss of full rook when in the second case
>>>it searches Rxd5 Bc4 Bc6
>>>
>>>Uri
>>Hi all,
>>
>>It's clearly seen that Rybka uses some form of selective search different from
>>others' in the quescence search which is not a full width search, therefore is
>>not counted in nps. This explains the low nps, Rybka does extra work in the QS
>>which pays off.
>>Obvious, that a usual 1 ply search cannot be such better even with a superb
>>evaluation but a Rybka-type can be.
>>
>>Regards,
>>László
>
>No
>
>It is not clear
>
>I can achieve the same effect by not counting nodes in the qsearch and writing
>depth x when the real depth is x+2
>
>It is possible that rybka does nothing special except playing better when vasik
>tries to hide what it does by misleading information.
>
>Uri
>Uri
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.