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Subject: Re: GreKo 2.03: depth 9 (+)

Author: Uri Blass

Date: 06:47:43 12/26/02

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On December 26, 2002 at 09:37:18, Vladimir Medvedev wrote:

>>How long does your program need to avoid Qxf1?
>>
>>[D] 1kr5/pp2bNp1/1qb1p3/3n4/P2PN3/1p1B2P1/1B2Q3/R4rK1/w - - ;am Qxf1
>>
>>In IsiChess some queen-pinned knowledge was helpfull.
>>4 seconds to avoid Qxf1 on AMD XP 2.1+ 256MB Hash.
>
>GreKo changes it's mind at depth 9, after 33 seconds.
>Hardware: Pentium-III, 600 MHz, 64 MB Hash.
>It knows nothing about pinning.
>
>
> 1     33      0       255  1. Qxf1 Rf8 White(1):
> 2     43      2      1169  1. Qxf1 Rf8 2. Qf2
> 3     24      5      4038  1. Qxf1 Rf8 2. Qf2 Qc7
> 4     42     26     26720  1. Qxf1 Rf8 2. Bb5 Nc7 3. Bd3
> 5     42     81     93746  1. Qxf1 Rf8 2. Bb5 Nc7 3. Bd3
> 6     26    128    148951  1. Qxf1 Rf8 2. Qf2 Qb4 3. Nc5 Bf6
> 7     22    416    496575  1. Qxf1 Rf8 2. Be2 Qb4 3. Bb5 a6 4. Bxc6 bxc6
> 8     16   3298   3580934  1. Rxf1 Bxa4 2. Ned6 Rc6 3. Ne8 Rc2 4. Qe5+ Ka8 5.
>Bxc2 bxc2
> 9    -10   7639   8506587  1. Rxf1 Bxa4 2. Neg5 Rc6 3. Ne5 Rc2 4. Bxc2 bxc2 5.
>Nc4 Bb5

Based on the analysis it changed it's mind at depth 8 but not all the analysis
is printed.

I see no score for Qxf1 at depth 8

Note that movei has knowledge about pins(it knows to extend in the qsearch when
the queen is pinned) but I think that the knowledge that is needed is different
and I see no line when the queen is pinned but only pin of the knight to the
queen(movei only knows about pins to the king).

Uri



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