Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Average Engine but a fascinating game !

Author: Alessandro Damiani

Date: 14:33:27 07/08/03

Go up one level in this thread


On July 08, 2003 at 10:40:28, Uri Blass wrote:

>On July 08, 2003 at 10:28:55, Djordje Vidanovic wrote:
>
>>On July 07, 2003 at 16:47:09, Uri Blass wrote:
>>
>>>On July 07, 2003 at 16:44:28, Djordje Vidanovic wrote:
>>>
>>>>Here's the clip from the newest Ruffian engine:
>>>>
>>>>New game
>>>>4rqn1/p3brk1/R5p1/6Bp/1p5Q/1B1R4/PPP2PPP/6K1 w - - 0 1
>>>>
>>>>Analysis by Ruffian 2003-06-23:
>>>>
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 1/7   00:00:00
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 1/7   00:00:00
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 2/7   00:00:00
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 3/10   00:00:00
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 4/10   00:00:00
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 5/11   00:00:00
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 6/13   00:00:00  16kN
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 7/17   00:00:00  86kN
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 8/20   00:00:00  202kN
>>>>1.Rxg6+ Kxg6 2.Rh3 Bxg5 3.Qxh5+ Kf5 4.Rf3+ Ke5 5.Rxf7 Qh6 6.Qe2+ Be3 7.fxe3
>>>>  +-  (7.53)   Depth: 9/20   00:00:00  448kN
>>>
>>>I suspect that it learned from previous analysis.
>>>The line and the score was not changed from depth 1.
>>>
>>>Uri
>>
>>
>>Which previous analysis?  I just copied the fen into Ruffian and let him
>>analyse. No previous analysis. Wrong suspicion :)  Ruffian is a very smart
>>program...
>>
>>Djordje
>
>It does not make sense that a program has a pv of 13 plies at depth 1 when the
>pv and the score are unchanged until depth 9 except number of nodes.
>

It is possible due to extensions. At depth 1 the PV is extended 13 plies deep.
The following iterations can produce the same pv and therefore the same score if
the extensions at depth 1 already produced the best sequence of moves up to ply
13.

This behaviour happens also with a simple full-width search followed by a
capture search: if at the horizon of the full-width search - on the pv - a
capture is forced, the next iteration will have the same pv with the same depth
and score.

Rgds,
Alessandro



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.