Author: Tim Foden
Date: 02:54:52 04/22/03
Go up one level in this thread
On April 22, 2003 at 05:34:57, Uri Blass wrote:
>On April 22, 2003 at 04:30:14, Sune Fischer wrote:
>
>>On April 22, 2003 at 04:14:44, Uri Blass wrote:
>>
>>>On April 22, 2003 at 03:13:41, Sune Fischer wrote:
>>>
>>>>On April 21, 2003 at 18:24:45, Drexel,Michael wrote:
>>>>
>>>>>On April 21, 2003 at 18:09:03, Uri Blass wrote:
>>>>>
>>>>>>On April 21, 2003 at 17:18:46, Robin Smith wrote:
>>>>>>
>>>>>>>On April 20, 2003 at 17:20:11, Uri Blass wrote:
>>>>>>>
>>>>>>>>It may be possible to use it in a productive way to avoid problems
>>>>>>>>that I mentioned(the program prefers loss by KR vs KPPP and not drawn KR vs KPP)
>>>>>>>>by having rules to trust tablebases scores only in part of the cases but I do
>>>>>>>>not like it.
>>>>>>>
>>>>>>>Uri,
>>>>>>>
>>>>>>>I know such things are possible in theory. Can you give an example of it
>>>>>>>actually happening?
>>>>>>>
>>>>>>>Robin
>>>>>>
>>>>>>No
>>>>>>If I remember correctly I saw a case when it happened but
>>>>>>I did not care to save the position and I do not plan
>>>>>>to look for it now.
>>>>>>
>>>>>>Uri
>>>>>
>>>>>[D] 8/8/8/7P/4K1P1/r6P/k7/8 b - - 0 1
>>>>>
>>>>>
>>>>>Anaconda 1.0 lost this position with tablebases.
>>>>>It would take the pawn without.
>>>>
>>>>It's a fluke.
>>>>
>>>>I think what happens here is that table bases tell the engine it has a draw if
>>>>it wants it, however the engine is "stupid" and believes it is better and will
>>>>not be satisfied with a draw.
>>>>
>>>>So it's a simple horizon problem as far as I can tell, the TBs provide
>>>>"infinite" depth but the engine does not like the truth it sees and prefers to
>>>>kid itself. Without TBs it doesn't know it choosing a drawing line, so it
>>>>happily eats the pawn.
>>>>
>>>>If the engine was a little better it would know the draw was the best option
>>>>anyway. I don't know about Anaconda, but Ruffian and Frenzee both get a draw
>>>>score showing pretty fast with TBs, so maybe this is related to a bug in
>>>>Anaconda?
>>>
>>>I think that it is related to the knowledge that frenzee and Ruffian has and
>>>ankadota and movei have not.
>>>Movei does not use tablebases so it plays the right move but
>>>Movei has a negative score for white after Ra4+ even after a long time and I
>>>hope that it will be changed after adding score of pawns relative to kings.
>>
>>Frenzee doesn't have any knowledge of this, but it also chooses the wrong move
>>Ra4+, and so does Yace btw. It's a little strange that they both show a draw
>>score for a non-drawing move, apparently they are content with a draw, so I'm
>>not sure why they don't chose Rxh4 immediatly.
>>Ruffian must have special knowledge so it is a bad example, it shows a draw
>>score from ply 1 :)
It doesn't on my machine without tablebases. It is close to a draw though.
ruffian: setboard 8/8/8/7P/4K1P1/r6P/k7/8 b
[setboard 8/8/8/7P/4K1P1/r6P/k7/8 b ]
ruffian: analyze
[analyze]
8/8/8/7P/4K1P1/r6P/k7/8 b - -
Depth Time Score Best line
1/1 6.41 0.34 ... Rxh3
1--> 8.47 0.34 ... Rxh3
2/3 8.47 0.24 ... Rxh3 Kf4
2--> 8.47 0.24 ... Rxh3 Kf4
3/4 8.47 0.54 ... Rxh3 Kf4 Kb2
3--> 8.47 0.54 ... Rxh3 Kf4 Kb2
4/6 8.47 0.75 ... Rxh3 Kf4 Kb3 Kf5
4--> 8.47 0.75 ... Rxh3 Kf4 Kb3 Kf5
5/9 8.47 0.96 ... Rxh3 Kf4 Kb3 Kf5 Rf3+ Kg5
5--> 8.47 0.96 ... Rxh3 Kf4 Kb3 Kf5 Rf3+ Kg5
6/10 8.48 -- ... Rxh3
6/10 8.48 0.45 ... Rxh3 Kf5 Rf3+ Ke4 Rg3 Kf4 Rd3 Kf5
6--> 8.49 0.45 ... Rxh3 Kf5 Rf3+ Ke4 Rg3 Kf4 Rd3 Kf5
7/13 8.50 0.59 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Rf3 g5
7--> 8.53 0.59 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Rf3 g5
8/13 8.54 0.38 ... Rxh3 Kf5 Kb3 Kg6 Rd3 g5 Rd6+ Kf5 Kc4
8--> 8.62 0.38 ... Rxh3 Kf5 Kb3 Kg6 Rd3 g5 Rd6+ Kf5 Kc4
9/14 8.65 0.39 ... Rxh3 Kf5 Rh4 Kg5 Rh1 h6 Kb3 Kg6 Kc4 g5
9--> 8.83 0.39 ... Rxh3 Kf5 Rh4 Kg5 Rh1 h6 Kb3 Kg6 Kc4 g5
10/18 8.94 0.28 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 h7 Rh4 g5 Ke5
10--> 9.33 0.28 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 h7 Rh4 g5 Ke5
11/19 9.52 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 h7 Ke5 Kg7 Kf4 h8=Q
Rxh8 Kxh8 Kxg4
11--> 10.52 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 h7 Ke5 Kg7 Kf4 h8=Q
Rxh8 Kxh8 Kxg4
12/22 10.75 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 h7 Ke5 Kg7 Kf4 h8=Q
Rxh8 Kxh8 Kxg4
12--> 12.55 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 h7 Ke5 Kg7 Kf4 h8=Q
Rxh8 Kxh8 Kxg4
13/24 13.62 -0.10 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf4 g6
Rd3
13--> 20.57 -0.10 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf4 g6
Rd3
14/27 21.54 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf5 h7
Kxg5 h8=Q Rxh8 Kxh8
14--> 30.92 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf5 h7
Kxg5 h8=Q Rxh8 Kxh8
15/27 32.60 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf5 h7
Kxg5 h8=Q Rxh8 Kxh8
15--> 51.75 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf5 h7
Kxg5 h8=Q Rxh8 Kxh8
16/28 54.70 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf5 h7
Kxg5 h8=Q Rxh8 Kxh8 Kh5
16--> 1:33 0.00 ... Rxh3 Kf5 Kb3 Kg6 Kc4 h6 Kd5 g5 Ke5 Kg7 Kf5 h7
Kxg5 h8=Q Rxh8 Kxh8 Kh5
exit... 1:33 1/16 Rxh3
{r}
Time: 1:36, cpu 85.32%, nodes 95179812, nps 989086
Hash: 16M, used 99%, hits 59%
EGTB: disabled
[r]
>I do not know.
>
>Does Ruffian show scores at ply 1 or 2?
No, see above. It may be different if tablebases are used I suppose.
>I never saw them.
>can you post analysis of Ruffian at depth 1 or 2?
Also see above. To do it I reduced the process priority of ruffian, and ran
another program at full CPU until ruffian showed its 1 ply message, then I
stopped the other program. The times/nps etc. are therefore not realistic, but
the scores and number of nodes will be.
Cheers, Tim.
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