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Subject: Re: How many programs can see the draw in the 2nd game of DB vs Kasparov?

Author: Dieter Buerssner

Date: 07:27:21 02/28/01

Go up one level in this thread


On February 28, 2001 at 05:56:27, Uri Blass wrote:

>On February 27, 2001 at 08:24:14, Jorge Pichard wrote:

>I helped yace by going forward and backward.
>
>yace liked 2.Qxd6 after 1...Qe3 so I had to tell it the moves that it wants to
>play (Re8 h4 h5 Bf3 Qc1+ Kf2 Qd2+ Be2 Qf4+ Kg1 and after playing these moves it
>can see the draw after enough time).
>
>After doing it I went back slowly and it found draw in all moves when only at
>move 3 it found an alternative 3.Qd7+ with 0.09 pawns for white.
>
>I continue to go back.
>
>It needed a long time to see that there is not a good alternative to 2.Qxd6 but
>after enough time it found that 2.Qd7+ has 0.00 evaluation and change its mind
>to 2.Qd6.

There is no need, to wait a long time here. I assume, that after Yace knew the
score after Qxd6, it switched to Qd7. Just do the move on the board (i.e. by
adding a variant to the movelist) and use the same method of above - just do the
suggested moves rather fast. A draw score will be shown soon. Then undo the
moves, and the drawscore should propagate back. This took me less than 2
minutes.

>I continued to go back and it evaluated 1...Qe3 as +0.09 for white
>Main line
>1...Qe3 2.Qxd6 Re8 3.Qd7+ Re7 4.Qc6 Qxe4 5.d6 Qd3+ 6.Kg1 Re8 7.Kh2 Qxf5 8.Ra2
>Rd8 9.Qxb5 Rxd6 10.Qxc4+ Kg6 11.Ra7 Kh7

I am not sure, if a draw can be prooven after the white Queen is on c6.

One note to people, that want to try this. Unfortunately, there is a small bug
in the UCI implementation of Yace. It will clear hash tables and the learned
information of subtree analysis, when the position is setup. This was a leftover
from my debugging, so that I could reproduce exact node counts, sorry. This
won't happen, when the game starts from the initial position, i.e. when you load
the whole game.

Regards,
Dieter




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