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Subject: Re: Ruffian's blind spot

Author: Tony Werten

Date: 00:50:58 05/20/03

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On May 20, 2003 at 02:17:14, Tim Foden wrote:

>On May 19, 2003 at 23:46:58, Will Singleton wrote:
>
>>I was trying to figure out why my latest build doesn't do quite as well on
>>ecm86, and I ran Ruffian on it.  To my surprise, Ruffian couldn't solve it, even
>>given 5 minutes.  This is odd, since most other progs can do it in less than 10
>>seconds.  (What I take away from this exercise is that my program must now be
>>stronger.  Otherwise, I'd have to work on the problem, which is much less
>>interesting than testing new ideas.)
>>
>>[D]2r3k1/1nqbrp2/p5pp/1p1Pp1N1/8/1P5P/P1B2PP1/2RQR1K1 w - -
>
>I would assume then (from running Green Light), that Nxf7 is the correct move
>here?
>
>The PV is interesting as it contains 9 captures in a row at the start of the PV.
> Maybe ruffian is pruning if there are more than a certain number of captures in
>a row (as this is very unlikely to be a good thing).

My guess is that Ruffian is a preprocessor, which can't handle 9 captures
because the position is so different ( root position compared to leaf position )

There is a good chance Fritz 5.32 will show the same beheavior.

Tony

>
>Cheers, Tim.
>
>Analysis:  GLC3.00, AXP 1.47GHz, 24MB Hash:
>
> Game stage: Middle game
> Current eval: 0.564
> Ply   Time   Score   Nodes  Principal variation
>  4   0.000  +0.743    5646  Ne4 Qb6 2. Qd2 g5
>  5   0.010  +0.592   13917  Ne4 Nd6 2. Nf6+ Kg7 3. Qf3 Kh8
>  5   0.020  +0.592   21231  Ne4 Nd6 2. Nf6+ Kg7 3. Qf3 Kh8
>  6   0.060  +0.702   54001  Ne4 Qb6 2. Qd2 g5 3. Qb4 Nc5
>  6   0.070  +0.702   66151  Ne4 Qb6 2. Qd2 g5 3. Qb4 Nc5
>  7   0.200  +0.709  159535  Ne4 Qb6 2. Bd3 Ree8 3. Qd2 g5 4. Nc3
>  7   0.310  +1.102  263663  Nxf7 {++} Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+
>                               Kxf7 5. Rxc1
>  7   0.360  +1.745  307058  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1
>  7   0.370  +1.745  316180  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1
>  8   0.440  +1.345  388531  Nxf7 {--} Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+
>                               Kxf7 5. Rxc1 Nd6
>  8   0.530  +1.186  460490  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6
>  8   0.580  +1.186  527044  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6
>  9   0.841  +1.259  749293  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7
>  9   1.081  +1.259  966741  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7
> 10   1.712  +1.299 1514631  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke7
> 10   2.093  +1.299 1853467  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke7
> 11   3.985  +1.340 3477228  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke7 7. g4
> 11   5.377  +1.340 4753269  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke7 7. g4
> 12   8.251  +1.405 7132424  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke8 7. Ra7 Bc8
> 12  11.666  +1.405  10151k  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke8 7. Ra7 Bc8
> 13  19.798  +1.603  16605k  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke8 7. Ra7 Bc8 8. Rc7
> 13  25.416  +1.603  21432k  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke8 7. Ra7 Bc8 8. Rc7
> 14  40.958  +1.591  33530k  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke8 7. Ra7 Bc8 8. Rh7 Nf7
> 14  58.534  +1.591  49298k  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke8 7. Ra7 Bc8 8. Rh7 Nf7
> 15 1:50.67  +1.731  89853k  Nxf7 Rxf7 2. Bxg6 Qxc1 3. Qxc1 Rxc1 4. Bxf7+ Kxf7
>                               5. Rxc1 Nd6 6. Rc7 Ke8 7. Ra7 Bc8 8. Rh7 Nf7 9.
>                               Rg7
>Analyse>exit
> local:  t=2:08.16  nps=823272.7  n=105513924 (19.4% / 80.6%)
> total:  t=2:08.16  nps=823272.7  n=105513924
> stats:  fh=92.6%/3.32%/1.144%  draws=27498
> trans:  probes=20409495  hits=2716707 (13.31%)  draft=1695895 (8.31%)
> tcuts:  exact=194 (0.00%)  upper=762653 (3.74%)  lower=739551 (3.62%)
> tstor:  exact=177 (0.00%)  upper=4357058 (62.62%)  lower=2600548 (37.38%)
> ext:  check=2656717  recap=312992  ppush=163771  1rep=165677  thrt=0
> q-moves:  gen=95505010  tested=42689594  made/un=16616552  max-dep=13
> max eval diff:  part-1=3.320  part-2=2.724



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