Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: After......42.....g5

Author: Enrique Irazoqui

Date: 06:31:37 10/18/00

Go up one level in this thread


On October 18, 2000 at 08:46:53, Uri Blass wrote:

>On October 18, 2000 at 08:09:28, Enrique Irazoqui wrote:
>
>>On October 18, 2000 at 03:54:08, Uri Blass wrote:
>>
>>>On October 17, 2000 at 20:53:45, Robert Hyatt wrote:
>>>
>>>>On October 17, 2000 at 14:25:32, Chessfun wrote:
>>>>
>>>>>On October 17, 2000 at 14:23:38, Chessfun wrote:
>>>>>
>>>>>>On October 17, 2000 at 14:22:19, Chessfun wrote:
>>>>>>
>>>>>>>On October 17, 2000 at 14:19:56, Enrique Irazoqui wrote:
>>>>>>>
>>>>>>>>On October 17, 2000 at 14:17:46, Chessfun wrote:
>>>>>>>>
>>>>>>>>>
>>>>>>>>>Rd7+ Re7 Qb3+ Kf8 Rd6 Nxe5 Qc3 b4
>>>>>>>>>depth 11 +3.18
>>>>>>>>
>>>>>>>>WHAT??? No way (I hope).
>>>>>>>>
>>>>>>>>Kramnik,V - Kasparov,G
>>>>>>>>8/5k1p/p1nRrp1P/PpP2qp1/4p3/4B3/1P3PP1/3Q2K1 w - - 0 1
>>>>>>>>
>>>>>>>>Analysis by Deep Fritz T28:
>>>>>>>>
>>>>>>>>43.Rd7+ Kg6 44.Rg7+ Kxh6 45.Qd7 Re5 46.Rxh7+ Qxh7 47.Qxc6 Kg6
>>>>>>>>  ²  (0.44)   Depth: 11/28   00:00:50  6786kN
>>>>>>>>  ²  (0.50)   Depth: 12/32   00:01:55  15933kN
>>>>>>>>
>>>>>>>>(Irazoqui, Cadaqués 17.10.2000)
>>>>>>>
>>>>>>>Still showing
>>>>>>>Rd7+ Re7 Qb3+ kf8 Rd6 Nxa5 Qc3 b4 Qxf6+ etc
>>>>>>>
>>>>>>>Depth 13. +2.84
>>>>>>>
>>>>>>>I'll check after Rd7+ Kg6
>>>>>>>
>>>>>>>Sarah.
>>>>>>
>>>>>>Added score.
>>>>>
>>>>>if Kg6
>>>>>Rg7+ Kxh6 Rc7 Qe5 QD7 Ne7 g4 Kg7 Bd4 Qxe6 Qxc7 Bxf6+ Kf8
>>>>>+3.88 Depth 12
>>>>>
>>>>>Sarah.
>>>>
>>>>
>>>>That eval is too big.  IE this is another example.  I don't recall this
>>>>exact position but white is either up 1 or 2 pawns (2 I think) but with
>>>>lots of holes and a queen and knight to deal with.
>>>>
>>>>Most programs had this as +1 to +1.3 in this stage of the game.  I became
>>>>less and less optimistic for white as I watched, as the queen is simply a real
>>>>pain, and the knight is the optimal piece to have working with the queen in a
>>>>board with pawns moved everywhere.
>>>>
>>>>I wasn't surprised by the outcome, particularly.  If programs say +2 or less,
>>>>draws don't cause any speculation or bug-hunting...
>>>>
>>>>I think the krnp vs kr might have been easier to win than this game was.  Of
>>>>course, taking time to eat the a-pawn in this game might have cost white more
>>>>than he thought...
>>>
>>>I suspect that the score of Krnp vs Kr of chess tiger is bigger so the fact that
>>>it is more easy to win does not say that the evaluation is wrong.
>>>
>>>Chesstiger did not like kramnik's moves so the fact that the game was drawn does
>>>not prove that the evaluation was wrong.
>>>
>>>The question is if chesstiger can win other programs.
>>>
>>>Uri
>>
>>In this particular case it seems that Gambit's evaluation was a mirage. I made
>>it play after Gambit's choice of 47.Rc7, giving Gambit, white, and Deep Fritz
>>beta, black, about 5 to 10 minutes/move each on 2 P600E, DF with 184MB hash,
>>Gambit with 192MB hash:
>>
>>Gambit 47.Rc7, +3.62
>>DF     47... Ne7, +0.94
>>Gambit 48.Qd8, +4.38
>>DF     48... Nd5, +0.66
>>Gambit 49.Rb7 (why?), +4.28
>>DF     49... Nxe3, 0.00
>>Gambit 50.Qf8+, +1.83 (failing low)
>>DF     50... Kh5, +0.19
>>Gambit 51.fxe3, +1.10 (lower)
>>DF     51... Re5, +0.19
>>
>>As seen by Gambit itself, the initial evaluations of this line were wrong.
>>
>>But I don't think that this is the right way to look at Gambit's evals, which in
>>these cases are speculative. It is not so much a matter of being accurate, of
>>seeing the whole line, but of making Gambit go for the attack, and more often
>>than not it succeeds.
>
>I am not against gambittiger but I believe that it is the right way to look at
>gambit's evaluations.

To find out about how Gambit works, yes. But I don't think it makes sense to
pretend that speculative evals are exact, or else they wouldn't be speculative.
That's what I meant.

>Christophe explained that he did not finish to tune gambit's evaluation and I
>believe that he is going to have better evaluation in the future.
>I guess that in this case slower time control can also help tiger to avoid
>49.Rb7 because the score dropped one move after it.

I left Gambit computing this move for almost an hour, and Rb7 was still the
choice.

>I see from the fact that tiger used 5-10 minutes per move that tournament time
>control is not slow ennough.

As I told you the other day, so far there is no evidence showing that Gmabit
does better at slow time controls. I tried this playing matches Gambit-Junior 6a
at game/10, 40/20 and 40/60 with similar results.

Enrique

>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.