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Subject: Re: Not too diffcult for computers

Author: David Rasmussen

Date: 13:06:00 01/15/01

Go up one level in this thread


On January 15, 2001 at 10:07:42, Uri Blass wrote:

>On January 15, 2001 at 08:33:46, David Rasmussen wrote:
>
>>On January 14, 2001 at 20:37:39, Djordje Vidanovic wrote:
>>
>>>On January 14, 2001 at 17:36:21, Dan Andersson wrote:
>>>
>>>>There is no problem. I suspect more than a few programs find Rxc6 in reasonable
>>>>times. The first program I tried actually found it quickly, the second too,
>>>>Crafty and Yace. Some others will find it later some sooner. Nothing tricky
>>>>about this position at all.
>>>>
>>>>Regards Dan Andersson
>>>
>>>
>>>Actually I believe that the position IS tough for some programs -- just look at
>>>the commercials listed that did not find the winning move.  Of the programs that
>>>I tested the quickest was Patzer 3.11b which found 1.Rxc6 in a second!  Also
>>>quick were Deep Fritz (about 20 sec), Gandalf 4.32g (20 sec), Ikarus (around 25
>>>sec), Fritz 5.32 (about 25 sec too), etc.  Some other programs could not find
>>>the sequence at all.  The issue here is mobility, I suspect.  I had thought that
>>>Phalanx would be fast, but after a minute passed and it had no clue, I gave it
>>>up.
>>>
>>>***  Djordje
>>
>>I don't understand why this can be hard. My program Chezzz is definitely weaker
>>than DF, Gandalf, Fritz 5.32, and probably some or all of the others you
>>mention, but still, Rxc6 is the _only_ move it ever considers, even at depth=1.
>>It never considers any other move at all. This takes 0.02 seconds on my Cel 464.
>
>I do not understand why your program considers Rxc6 even at depth 1 because this
>move is losing material at depth 1.
>I suspect that your program is not materialistic enough and can play sacrifices
>that are not correct.
>
>Uri

Chezzz is not very positional. It is fairly materialistic (unfortunately).
Accumulated positional scores stay well below one pawn in most positions, and in
this one too.
Judge for yourself.

Thinking for 11 seconds.
time    depth   val     variation
0.01    1/2     -2.32   32. Rxc6 dxc6 (0 kN)
0.01    1/2     ----->  36 nodes        3600 nps        q 11%   mo 50%  h 0%
0.02    2/3     -2.32   32. Rxc6 dxc6 (0 kN)
0.03    2/3     ----->  176 nodes       5866 nps        q 14%   mo 93%  h 0%
0.04    3/5     -2.32   32. Rxc6 dxc6 33. Rd3 (0 kN)
0.06    3/5     ----->  1271 nodes      21183 nps       q 9%    mo 89%  h 0%
0.06    4/7     -2.32   32. Rxc6 dxc6 33. Rd3 Rb4 (1 kN)
0.10    4/7     ----->  4513 nodes      45130 nps       q 13%   mo 86%  h 6%
0.11    5/8     -1.99   32. Rxc6! (5 kN)
0.13    5/7     -1.47   32. Rxc6 dxc6 33. Kxc6 Rc8+ 34. Kd6 Rc3 (7 kN)
0.17    5/8     ----->  11661 nodes     68594 nps       q 11%   mo 88%  h 17%
0.20    6/9     -1.43   32. Rxc6 dxc6 33. Kxc6 Rf8 34. Rd3 Rc8+ 35. Kd5 (14 kN)
0.26    6/9     ----->  21880 nodes     84153 nps       q 11%   mo 90%  h 14%
0.29    7/10    -1.27   32. Rxc6 dxc6 33. Kxc6 Rf8 34. Kc7 Ra8 35. Rd7 (26 kN)
0.52    7/11    ----->  53572 nodes     103023 nps      q 7%    mo 90%  h 12%
0.59    8/11    -0.94   32. Rxc6! (62 kN)
0.71    8/11    -0.67   32. Rxc6 dxc6 33. Kxc6 Kf8 34. Rd8+ Rxd8 35. Bxd8 Kg7
                        36. Bxa5 (79 kN)
1.09    8/12    ----->  134719 nodes    123595 nps      q 8%    mo 91%  h 30%
1.22    9/13    -0.73   32. Rxc6 dxc6 33. Kxc6 Kf8 34. Rd8+ Rxd8 35. Bxd8 Ke8
                        36. Bxa5 Ke7 (153 kN)
2.01    9/14    ----->  269689 nodes    134173 nps      q 7%    mo 92%  h 33%
2.35    10/15   -0.54   32. Rxc6 dxc6 33. Kxc6 Kf8 34. Kc7 Ra8 35. Kb7 Re8
                        36. Rd5 Re6 37. Rxa5 (317 kN)
3.18    10/17   ----->  444676 nodes    139835 nps      q 7%    mo 92%  h 36%
3.66    11/17   -0.54   32. Rxc6 dxc6 33. Kxc6 Kf8 34. Kc7 Ra8 35. Kb7 Re8
                        36. Rd5 Re6 37. Rxa5 (508 kN)
5.36    11/19   ----->  775098 nodes    144607 nps      q 7%    mo 92%  h 35%
6.57    12/19   -0.39   32. Rxc6 dxc6 33. Kxc6 Kf8 34. Rd5 Rc8+ 35. Kb7 Re8
                        36. Rxa5 Re6 37. Ra8+ Re8 38. Ra7 Re6 (952 kN)
11.00   12      25/27   R2d5
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