Author: Bernhard Bauer
Date: 23:45:39 04/07/98
Go up one level in this thread
On April 08, 1998 at 01:56:58, Christophe Theron wrote:
>On April 06, 1998 at 09:49:25, blass uri wrote:
>
>>
>>On April 06, 1998 at 05:33:45, Sylvain Renard wrote:
>>
>>>
>>>On April 06, 1998 at 03:35:06, Roland Pfister wrote:
>>>>Patzer found Qe3 in 3:08 but it thinks it is a mate in 15 :-(
>>>>I thought I had found that bug...
>>> Capture plays Qe3 very quickly and see mate in 9 in less than
>>>2 minutes (P PRO 200 MHz). The bug of Fritz 5 is vey strange,
>>>someone as an idea of its origine?
>>> Sylvain
>>
>>The evaluation function of fritz5 was:
>>6.09 9/18
>> 5.78 10/20
>> 5.47 11/22
>> 5.16 12/25
>> 4.84 13/25
>>4.53 14/28
>>4.22 15/30
>>3.91 16/32
>>3.59 17/34
>>3.28 18/36
>>2.97 19/38
>>I think this is something like 9-0.31*d when d is the depth of bruth
>>force
>>maybe fritz5 do some average between its evaluation by brute force
>>and the eveluation of not brute force and use the depth.
>>fritz4 and fritz3 have similiar bug fritz3 go almost to 0 but then go
>>back
>>in depth 16 it's evaluation is 0.13 and in depth 17 is 0.44 (in depth 15
>>0.44
>>and in depth 14 0.75)
>
>I think it's a zugzwang problem. I don't know exactly why, but it looks
>like the black queen has to stay on the a1-h8 diagonal (or else the
>white queen goes on this diagonal, check, and mate in 2), and has also
>to stay on the the a file.
>
>Or something like that. Anyway, I think black is quickly caught in
>zugzwang.
>
>Programs relying on null move like Fritz (and maybe Crafty?) have
>problems with this, because a general rule in those programs is that
>they don't care of zugzwang problem if the queens are on the board. This
>is correct 99.99% of the time, but not in this position...
>
Here is some output from crafty:
White(1): hash table memory = 6M bytes.
White(1): pawn hash table memory = 1.3M bytes.
+---+---+---+---+---+---+---+---+
8 | | | | | | | | *K|
+---+---+---+---+---+---+---+---+
7 | | | | | K | | | *P|
+---+---+---+---+---+---+---+---+
6 | | | | | | | | P |
+---+---+---+---+---+---+---+---+
5 | | | | *P| | | Q | |
+---+---+---+---+---+---+---+---+
4 | | | | | | | | |
+---+---+---+---+---+---+---+---+
3 | | | | | | | | |
+---+---+---+---+---+---+---+---+
2 | | | | | | | | |
+---+---+---+---+---+---+---+---+
1 | *Q| | | | | | | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
White(1): end-game phase
clearing hash tables
time surplus 0.00 time limit 5:00 (5:00)
depth time score variation (1)
6-> 0.84 0.29 1. Qf4 Qa7+ 2. Ke6 Qb6+ 3. Kxd5 Qb3+
4. Kc5 Qe6 5. Qf8+
7-> 1.79 0.00 1. Qf4 Qa7+ 2. Ke6 Qb6+ 3. Kxd5 Qb5+
4. Ke6 Qe8+ 5. Kf6 Qf8+ 6. Kg5 Qxf4+
7. Kxf4
8-> 3.70 0.12 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qe1+ 4.
Kxd5 Qd2+ 5. Ke5 Qd3
9-> 5.00 0.22 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4.
Ke5 Kg8 5. Kxd5 Qb6
10-> 9.78 0.00 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4.
Kxd5 Qb5+ 5. Ke6 Qe8+ 6. Kf6 Qf8+ 7.
Kg5 Qxf4+ 8. Kxf4
11-> 16.43 0.00 1. Qe3 Qb2 2. Ke6 Qa1 3. Qf4 Qa6+ 4.
Kxd5 Qb5+ 5. Ke6 Qe8+ 6. Kd5 Qf7+ 7.
Qxf7
12 22.23 ++ 1. Qe3!!
12 29.48 Mat09 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qg7 4.
hxg7+ Kxg7 5. Kxd5 <EGTB>
12-> 47.53 Mat09 1. Qe3 Qb2 2. Ke6 Qa1 3. Qb6 Qg7 4.
hxg7+ Kxg7 5. Kxd5 <EGTB>
time: 47.54 cpu:0% mat:-1 n:4443263 nps:93444
ext-> checks:825089 recaps:8581 pawns:15123 1rep:134501
predicted:0 nodes:4443263 evals:370831
endgame tablebase-> probes done: 37303 successful: 37303
hashing-> trans/ref:63% pawn:99% used:w93% b99%
Crafty will mate in 9 moves.
So crafty seems to be pretty good on this problem.
Kind regards
B. Bauer
White(1): Qe3
time used: 47.56
Black(1): execution complete.
>More help wanted... Can somebody prove that black is in zugzwang in some
>important variant of this position?
>
>
> Christophe
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