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Subject: Re: Test position and Crafty slow down

Author: Bernhard Bauer

Date: 06:58:09 11/10/99

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On November 10, 1999 at 09:09:20, Robert Hyatt wrote:

>On November 10, 1999 at 04:45:53, Bernhard Bauer wrote:
>
>>On November 10, 1999 at 04:07:49, Dann Corbit wrote:
>>
>>>On November 10, 1999 at 03:37:47, Bernhard Bauer wrote:
>>>>On November 09, 1999 at 17:17:06, James Robertson wrote:
>>>[snip]
>>>>I gave this position to crafty and did a search Nd5. Here are the results for
>>>>crafty16.19 and crafty17.0.
>>>>
>>>>Crafty16.19
>>>>===========
>>>>
>>>>  12->  11.30  -0.07   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                       4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 Nd7 7.
>>>>                       Ng5 Qc2 8. Ne6+ Ke7 9. Rd3 Qxa2 10.
>>>>                       Nxg7
>>>>  13    27.83   0.13   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                       4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 a5 7.
>>>>                       Qf5 Ba6 8. Rc1 Qxc1 9. Rxc1 Rxc1+
>>>>  13->  27.83   0.13   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                       4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 a5 7.
>>>>                       Qf5 Ba6 8. Rc1 Qxc1 9. Rxc1 Rxc1+
>>>>  14    44.83     ++   1. Nd5!!
>>>>  14->   1:18   0.52   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                       4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 a5 7.
>>>>                       Qf5 Ba6 8. Rc1 Qxc1 9. Rxc1 Rxc1+
>>>>  15     2:12     ++   1. Nd5!!
>>>>  15->   8:59   0.91   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                       4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 a5 7.
>>>>                       Qf5 Ba6 8. Rc1 Qxc1 9. Rxc1 Rxc1+
>>>> time=15:00  cpu=199%  mat=0  n=476806687  fh=96%  nps=529508
>>>> ext-> checks=46001900 recaps=737487 pawns=154520 1rep=5107499 thrt:139967
>>>> predicted=0  nodes=476806687  evals=31020644
>>>> endgame tablebase-> probes done=0  successful=0
>>>> SMP->  split=1274  stop=164  data=10/64  cpu=29:59  elap=15:00
>>>>
>>>>and
>>>>crafty17.0
>>>>==========
>>>>
>>>> 12->  15.23  -0.67   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 Nd7 7.
>>>>                      Ng5 Qc2 8. Ne6+ Ke7 9. Rd3 Qxa2 10.
>>>>                      Nxg7
>>>> 13    30.92  -0.60   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 a5 7.
>>>>                      Bg6 Qc5 8. e4 Nd7
>>>> 13->  30.92  -0.60   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 a5 7.
>>>>                      Bg6 Qc5 8. e4 Nd7
>>>> 14    46.22     ++   1. Nd5!!
>>>> 14->   1:35  -0.21   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Rc8 6. Nxf7 a5 7.
>>>>                      Bg6 Qc5 8. e4 Nd7
>>>> 15     3:43   0.00   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Ke7 6. Nxf7 Rc8 7.
>>>>                      Qf5 Kf8 8. Qf4 Ke7 9. Qf5
>>>> 15->   3:43   0.00   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Ke7 6. Nxf7 Rc8 7.
>>>>                      Qf5 Kf8 8. Qf4 Ke7 9. Qf5
>>>> 16    10:51   0.00   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Bxg5 6. Qh8+ Ke7
>>>>                      7. Qxg7 Rf8 8. Qxg5+ Ke8 9. Rc1 Qd8
>>>>                      10. Qf5 Nd7 11. a3 Qf6
>>>> 16->  10:51   0.00   1. Nd5 exd5 2. Bxf6 Bxf6 3. Qxh7+ Kf8
>>>>                      4. cxd5 d6 5. Bh5 Bxg5 6. Qh8+ Ke7
>>>>                      7. Qxg7 Rf8 8. Qxg5+ Ke8 9. Rc1 Qd8
>>>>                      10. Qf5 Nd7 11. a3 Qf6
>>>>time=15:00  cpu=200%  mat=0  n=314623673  fh=93%  nps=349445
>>>>ext-> checks=16736788 recaps=643735 pawns=162104 1rep=1411877 thrt:97472
>>>>predicted=0  nodes=314623673  evals=206046602
>>>>endgame tablebase-> probes done=0  successful=0
>>>>hashing-> trans/ref=23%  pawn=2%  used=99%
>>>>SMP->  split=1349  stop=171  data=10/64  cpu=30:01  elap=15:00
>>>>
>>>>Comparing these results show:
>>>>
>>>>              Crafty16.19   Crafty17.0
>>>>score(15)         0.91          0.0
>>>>nps             529508       349445
>>>>
>>>>So for this position crafty16.19 looks much better than crafty17.0.
>>>>Crafty17.0 is 34% slower than crafty16.19, not to mention the evaluation.
>>>>BTW computation was done on a 2xPIII 450MHz computer running WinNT4.0.
>>>Actually, crafty 17.0 beat the pants off of 16.19.  It finished ply 15 at 3:43
>>>compared to 8:59 so it looks to be much more than twice as fast.  The nodes mean
>>>nothing compared to finishing a ply.
>>
>>IMHO finishing a ply means nothing compared to finding the right continuation.
>>Please note that crafty16.19 gives a different line which looks mutch better.
>>So I wouldn't say "crafty 17.0 beat the pants off of 16.19". Such a statement
>>looks somewhat superficial.
>>Anyway, up to now there is no known reason why the new crafty is significantly
>>slower than 16.19. See the current discussion at the crafty mailing list.
>>Kind regards
>>Bernhard
>
>
>As I mentioned on the mailing list, comparing NPS between two versions is a
>good idea, but _not_ with mt=2 enabled.  There are too many variables, and the
>nps will vary significantly.  mt=2 is the right way to _run_ tests, but it is
>the wrong way to run if you want to compare nps, or time to finish a ply.  You
>have to run the same test dozens of times and take the average to get reasonable
>results...

Agreed.
So I ran the position again with mt=1. Note that all moves were searched.
      Crafty16.19      Crafty17.0
nps        232665          176095
total time    900 sec         900 sec
ply=8        17.2 sec        51.4 sec
ply=9        64   sec       109   sec
ply=10      171   sec       283   sec
ply=11      478   sec       784   sec
ply=12      834   sec       not completed

By this data Crafty17.0 is 24 % slower than Crafty16.19.
Kind regards
Bernhard



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