Author: Dann Corbit
Date: 21:40:15 12/08/05
Go up one level in this thread
On December 08, 2005 at 23:57:51, Uri Blass wrote:
>On December 08, 2005 at 23:35:36, Dann Corbit wrote:
>
>>On December 08, 2005 at 23:19:39, Uri Blass wrote:
>>
>>>On December 08, 2005 at 19:32:53, Dann Corbit wrote:
>>>
>>>>On December 08, 2005 at 19:09:42, Uri Blass wrote:
>>>>
>>>>>On December 08, 2005 at 18:27:01, Claude Le Page wrote:
>>>>>
>>>>>>Sevral posts have noticed that Rybka is rather weak in endgames ,especially
>>>>>>against Junior : this put me on apossible track : when its position is not
>>>>>>clearly better , a Juhior engine uses its fastness to complicate , and Rybka
>>>>>>must follow at maximum depth ,what is very costly in time : so , in endgame ,
>>>>>>Rybka is in zeitnot , and analyzes only at depth 13 where thr other is at depth
>>>>>>17
>>>>>>The same happens between Junior and Hiarcs : Their Knowledge slowen hem too
>>>>>>much in front of engines that use long calculated lines
>>>>>>The same seem to happen vs TogaII 1.1a , whose style is similar to Juniors
>>>>>>Could this be a possible explanation?
>>>>>
>>>>>The reason that rybka has problems in endgame is simply lack of knowledge about
>>>>>the endgame.
>>>>>
>>>>>I do not understand why people try to find other excuses.
>>>>
>>>>Perhaps Rybka is a program that could benefit greatly from EGTB (such that a
>>>>clear increase in Elo does occur from their use).
>>>
>>>I think that it can earn more from endgame knowledge.
>>
>>It is an interesting idea to me to try it both ways. I am thinking about it
>>this way:
>>
>>Adding endgame knowledge will slow down the eval.
>
>It is not a problem for rybka.
>
>As Vasik explained in the readme file
>
>"Rybka aims to have a fully knowledgeable evaluation function. This term however
>has taken some abuse recently, so let me make something clear: chess knowledge
>wins chess games. If it doesn't, it isn't knowledge."
>
>It already has a lot of middlegame knowkledge in the evaluation and it is
>productive and it is clear that adding endgame knowledge is an easier task as
>Vasik said in one of his posts.
>
>
> Perhaps leaving it out and
>>allowing the EGTB to handle endgame is good enough. But what happens when you
>>have not got all the way to EGTB land (e.g. 10 chessmen on the board).
>
>You cannot expect more than 7 piece tablabases in the next few years so I do not
>think that it is relevant.
If there are ten chessmen on the board, then 4 captures means 6 men hits.
Crafty sometimes probes endgames when lots of chessmen are left on the board.
For instance, with 14 chessmen and 5 man tablebase files, I got ten probes here:
[D]3bkb2/3pnp2/4q3/8/8/4Q3/3PNP2/3BKB2 w - -
White(1): epdpfga \probetest.epd probetest.out
PFGA: EPD record: 1
clearing hash tables
time surplus 0.00 time limit 16:39 (+0.00) (16:39)
depth time score variation (1)
8 0.84 0.13 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Ke2 Bb6 4.
Ba4 f5 5. Kd3
8 1.17 0.27 1. Bb3 Qf6 2. Bg2 Qa1+ 3. Bd1 Bg7 4.
Be4 Ba5 5. Nf4
8-> 1.44 0.27 1. Bb3 Qf6 2. Bg2 Qa1+ 3. Bd1 Bg7 4.
Be4 Ba5 5. Nf4
9 1.67 0.10 1. Bb3 Qf6 2. Bg2 Qa1+ 3. Bd1 Bg7 4.
Be4 Bc7 5. Nf4 Bd4
9 2.25 0.11 1. Bh3 Qc6 2. Bb3 Bg7 3. d4 Ba5+ 4.
Kd1 Qh1+ 5. Kc2 Qc6+ 6. Nc3 d5
9-> 3.78 0.11 1. Bh3 Qc6 2. Bb3 Bg7 3. d4 Ba5+ 4.
Kd1 Qh1+ 5. Kc2 Qc6+ 6. Nc3 d5
10 5.77 0.15 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Bf1 Bh6 4.
Qe5 Kf8 5. d3 Ng6 6. Qe4
10-> 8.17 0.15 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Bf1 Bh6 4.
Qe5 Kf8 5. d3 Ng6 6. Qe4
11 38.69 0.26 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Ke2 Qa8 4.
Bc2 Bb6 5. Qe5 Qa7 6. Nb5 Qb7
11-> 42.52 0.26 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Ke2 Qa8 4.
Bc2 Bb6 5. Qe5 Qa7 6. Nb5 Qb7
12 1:03 0.27 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Ke2 Qd5 4.
Bb3 Qh5+ 5. Qf3 Qxf3+ 6. Kxf3 Bb6 7.
Nb5 Nc6 8. Bf5 Bg7
12-> 1:17 0.27 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Ke2 Qd5 4.
Bb3 Qh5+ 5. Qf3 Qxf3+ 6. Kxf3 Bb6 7.
Nb5 Nc6 8. Bf5 Bg7
13 2:18 0.34 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Ke2 Qa8 4.
Nb5 Qd5 5. Ba4 Qh5+ 6. Kf1 Bh6 7. Nd6+
Kf8 8. Qd3 Qd5 9. Qxd5 Nxd5 10. d4
13-> 2:49 0.34 1. Bh3 Qc6 2. Nd4 Qh1+ 3. Ke2 Qa8 4.
Nb5 Qd5 5. Ba4 Qh5+ 6. Kf1 Bh6 7. Nd6+
Kf8 8. Qd3 Qd5 9. Qxd5 Nxd5 10. d4
14 5:56 0.40 1. Bh3 Qxe3 2. dxe3 Ba5+ 3. Kf1 Bg7
4. Ba4 Nc6 5. Kg2 Ke7 6. Bf5 Bb6 7.
Kg3 <HT>
14-> 7:34 0.40 1. Bh3 Qxe3 2. dxe3 Ba5+ 3. Kf1 Bg7
4. Ba4 Nc6 5. Kg2 Ke7 6. Bf5 Bb6 7.
Kg3 <HT>
15 12:09 0.41 1. Bh3 Qxe3 2. dxe3 Ba5+ 3. Kf1 d5
4. Ba4+ Kd8 5. Bb3 Bh6 6. Ng3 Bb6 7.
Ke2 Kc7 8. Nf5 Nxf5 9. Bxf5 Kc6 10.
Kf3
time=16:39 mat=0 n=1230558683 fh=92% nps=1.23M
ext-> chk=91056010 cap=3089816 1rep=4459212 mate=190814
predicted=0 nodes=1230558683 evals=870169208 50move=0
endgame tablebase-> probes=10 hits=10
SMP-> split=0 stop=0 data=0/32 elap=16:39
White(1):
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