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Subject: Re: Checks in qsearch - example

Author: Vincent Diepeveen

Date: 14:42:17 06/22/00

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On June 22, 2000 at 08:36:13, Robert Hyatt wrote:

>On June 22, 2000 at 08:03:25, Vincent Diepeveen wrote:
>
>>In games versus crafty you usual can escape to a draw in open positions with
>>queens, as it misses checks in qsearch. Take this objectively as that this
>>is not a complaint against crafty, because on the other hand crafty
>>searches non-checking lines usual deeper because of not doing checks in
>>qsearch.
>>
>>The only risk i run with diep is that it wants to win too much in those
>>queen pos.
>>
>>At fics old diep version (last linux compile from months ago)
>>runs under diep against a crafty.
>>
>>Move  diep               roboElvis
>>  1.  d4      (0:01)     Nf6     (0:01)
>>  2.  c4      (0:00)     e6      (0:00)
>>  3.  Nf3     (0:00)     d5      (1:40)
>>  4.  Nc3     (0:00)     c5      (0:00)
>>  5.  cxd5    (0:00)     Nxd5    (0:00)
>>  6.  e3      (0:00)     Nc6     (0:00)
>>  7.  Bc4     (0:00)     cxd4    (1:41)
>>  8.  exd4    (0:00)     Bb4     (1:40)
>>  9.  Qd3     (0:00)     Nb6     (2:40)
>> 10.  Bb3     (2:56)     Nd7     (0:01)
>> 11.  Qd1     (1:43)     O-O     (1:18)
>> 12.  O-O     (1:41)     Nf6     (0:05)
>> 13.  Bg5     (1:33)     h6      (1:31)
>> 14.  Bf4     (0:04)     Na5     (1:16)
>> 15.  Ba4     (0:23)     Nc4     (1:53)
>> 16.  Qb3     (1:18)     Bxc3    (1:12)
>> 17.  bxc3    (1:16)     Na5     (0:49)
>> 18.  Qc2     (1:15)     Nd5     (0:01)
>> 19.  Bg3     (1:15)     Bd7     (0:07)
>> 20.  Bxd7    (1:07)     Qxd7    (0:04)
>> 21.  Ne5     (1:10)     Qd8     (0:06)
>> 22.  Rfc1    (1:17)     Rc8     (1:17)
>> 23.  Qb2     (0:00)     a6      (1:25)
>> 24.  c4      (1:10)     Ne7     (1:10)
>> 25.  Qb4     (0:00)     Nf5     (1:09)
>> 26.  Nf3     (0:01)     Re8     (1:06)
>> 27.  Be5     (1:11)     f6      (1:07)
>> 28.  Bg3     (1:11)     Re7     (0:12)
>> 29.  d5      (1:00)     exd5    (0:16)
>> 30.  cxd5    (0:53)     Rxc1+   (0:13)
>> 31.  Rxc1    (0:56)     Rd7     (0:11)
>> 32.  Qe1     (0:56)     Kh8     (1:32)
>> 33.  Bf4     (1:07)     g5      (0:00)
>> 34.  Bd2     (1:31)     Rxd5    (0:01)
>> 35.  Bc3     (1:33)     Nc6     (0:00)
>> 36.  Qe6     (1:01)     Nfd4    (1:08)
>> 37.  Nxd4    (1:01)     Nxd4    (0:06)
>> 38.  Qe4     (0:54)     Rc5     (0:14)
>> 39.  h4      (0:45)     Rc4     (1:20)
>> 40.  hxg5    (1:00)     hxg5    (1:07)
>> 41.  f4      (0:52)     Qb6     (1:07)
>> 42.  Qe8+    (0:00)     Kg7     (1:05)
>> 43.  Qe7+    (0:00)
>>      {Still in progress} *
>>
>>Qb6? Diep directly saw a draw!
>>diep(C)(2177)[27] whispers: pv = 00:21 950233 (96172) 9 -0.15 h4xg5 h6xg5
>>\   Bc3-b2 Rc4xc1 Bb2xc1 Nd4-c6 Qe4-f3 Kh8-g7 Bc1-b2 Qd8-d6
>>fics%
>>diep(C)(2177)[27] whispers: pv = 00:46 4915150 (1081413) 9 -0.12 f2-f4 Qd8-b6
>>\   Qe4-e8 Kh8-g7 Qe8-e7 Kg7-g6 Qe7-e8 Kg6-f5 Qe8-d7 Nd4-e6 Kg1-h1 Qb6-c6
>>\   Qd7-d3 Kf5xf4
>>fics%
>>diep(C)(2177)[27] whispers: pv = 00:48 2237499 (417374) 10 0.00 Qe4-e8 Kh8-g7
>>\   Qe8-e7 Kg7-g6 Qe7-e8 Kg6-f5 Qe8-d7 Kf5-g6 Qd7-e8
>>fics%
>>diep(C)(2177)[27] whispers: pv = 00:33 1446958 (247075) 10 0.00 Qe8-e7 Kg7-g6
>>\   Qe7-e8 Kg6-f5 Qe8-d7 Kf5-g6 Qd7-e8
>>
>>I didn't see kibitzes from crafty. I wonder what depth crafty sees
>>Qb6 is a draw.
>>
>>Vincent
>>
>
>
>
>I don't think the depth here matters.  It depends on whether one program
>thinks it is behind or not, as to whether it is going to see the draw.  One
>side can force the draw.  If a program thinks that side is ahead, then it will
>think it best to avoid the draw, and it won't see it ever.
>
>I try to fix things that I believe are costing me games.  I don't see this
>happening often enough to offset the depth it gets in non-checking lines which
>helps it see more non-checking things.

White is behind a pawn. Just before seeing this checking sequence score
got up from -0.59 to -0.12 to 0.00

Again: I can't blame you from not doing checks. It's simply a choice you
make. In blitz at icc i'm quite
sure that getting another ply, so getting from 7 to 8 ply is usual
more important as getting from 10 to 11.

Yet when getting huge search depth, so 10 and beyond, if checks would
only eat at most a ply in heavy tactical open positions, then i prefer
doing the checks as you miss otherwise 4 ply (i'm using R=3 in DIEP therefore
instead of 2).

My vision of qsearch is that it should be as accurate as possible, without
wasting too much nodes in qsearch.

Vincent




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