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Subject: Re: Mate in 1 - but Fritz 6 needs 1 hour!!!

Author: Tim Foden

Date: 14:23:32 08/10/00

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On August 10, 2000 at 16:17:47, Christoph Fieberg wrote:

>Unbelievable, but true:
>I composed a position which is mate in 1 and can easily found, but Fritz6 on
>Pentium III, 500 Mhz and 32 MB Hash needs more than 1 hour to show it (excatly
>1:03:17)!!!
>How do other computers react?
>
>The position is
>FEN: [D]8/8/pppppppK/NBBR1NRp/nbbrqnrP/PPPPPPPk/8/Q7 w - - 0 1

Green Light takes just over 29 seconds on my K6/2 333Mhz:

------------------
 fen 8/8/pppppppK/NBBR1NRp/nbbrqnrP/PPPPPPPk/8/Q7 w - - 0 1
 Game finished test: 0
 time limit 178.00
 Game stage: Opening
 Current eval: -0.21
 Ply    CE  Time     Nodes  Principal variation
  1     ++    23     18913  Nxc6    (a=-0.71 b=0.29 e=0.29)
  1     35   107     94418  Nxc6
  1    245   221    194150  Nxc4
  1    431   249    225981  Nxd4
  1    488   250    227290  Rxd4
  1    521  1771   1641120  fxe4
  1    719  2891   2779247  dxe4
  1  32099  2907   2795807  Qh1#
  1  32099  2908   2795811  Qh1#
 Max eval diff 1 2.39, 2 0.98
 local:  t=29.08  nps=96135.4  n=2795811  (f=3  q=2795808)
 total:  t=7:30  nps=110487.0  n=49749871
 extensions:  check=2  recapture=0  pawn push=0  1-reply=0
 q-moves:  generated=9774356  considered=5271969  made/unmade=2795759
 !Qa1-h1 32099
move Qa1-h1
--------------------

The major reason for the time usage is the quiescence search, which it the bit
that searches until all potential capture gains have been found.

If you look carfully... GLC has only searched full alpha-beta 3 nodes!!
But it searched 2,795,808 quiecence nodes.

Cheers, Tim.



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