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Subject: Re: Very easy mate to solve.

Author: Heiner Marxen

Date: 18:45:09 12/22/01

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On December 22, 2001 at 20:23:43, leonid wrote:

>On December 22, 2001 at 17:21:52, Heiner Marxen wrote:
>
>>On December 22, 2001 at 09:21:12, leonid wrote:
>>
>>>Hi!
>>>
>>>This one is very accessible:
>>>
>>>[D]2qQQq2/r6P/b1PqqR1N/r6B/n1BRQQ1B/q6k/q1NKNP1q/bq4qn w - -
>>
>>According to Chest this is a mate in 9.  And yes, it is easy: just 101 seconds
>>on my K7/600:
>
>Hi, Heiner!
>
>Your time look like very good. When I saw your time I wanted to go back and see
>my for nine moves for brute force, but finally forgot to try this. Had very busy
>day with my work that I brought home.
>
>At least, time for brute force up to 8 moves is:
>
>Moves           Time          Branching factor             NPS
>
>4               0.82 sec                                   91k
>                              6.6
>5               5.43 sec                                   71k
>                              5.8
>6               31.8 sec                                   59k
>                              4.97
>7               2 min 35 sec                               51k
>                              4.13
>8               10 min 41 sec                              51k
>
>Cheers,
>Leonid.

My timing:

#  1      0.00s                 0kN           0.87          1-         0
#  2      0.00s                 0kN           1.00          1-         0
#  3      0.02s                 1kN [ 15.01]  0.96         70-         0
#  4      0.14s [  7.00]       11kN [  8.31]  1.06        546-         0
#  5      0.83s [  5.93]       55kN [  5.14]  1.28       3548-         0
#  6      4.06s [  4.89]      253kN [  4.60]  1.61      19237-         0
#  7     13.95s [  3.44]      825kN [  3.26]  2.91      67658-         0
#  8     42.52s [  3.05]     2414kN [  2.93]  5.04     205998-         9
#  9    101.03s [  2.38]     5642kN [  2.34]  7.81     487627-      4549

Once more our EBF is quite comparable, and even the nodes/second.
I'm a bit puzzled how your program does that without a hash table?

Obviously your move ordering is a bit better, while my basic speed
(as seen from the small depthes) is better.  The hash table does not make
that big a difference.

Sometimes I have seen (from experiments with Chest) that a bad move ordering
is in part compensated by the hash table, and a good move ordering greatly
decreases the additional effect of the hash table.
This effect seems to be involved here.

Cheers,
Heiner



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