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Subject: Re: What do you do in your qsearch?

Author: José Carlos

Date: 07:11:49 11/06/03

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On November 06, 2003 at 09:52:22, Robert Hyatt wrote:

>On November 06, 2003 at 04:51:38, José Carlos wrote:
>
>>  This position is easy, but interesting:
>>
>>[D]r2qk2r/pp3ppp/2pbpn2/4Nb2/PnBP2P1/2N1P3/1P3P1P/R1BQ1RK1 b kq g3 0 1
>>
>>  Black plays Ng4 with big advantage.
>>  Anubis (complex qsearch) finds it in iteration 8, while Averno (simple
>>qsearch) needs 12. Studying what the program was searching in qsearch in this
>>position has been very interesting for me.
>>  How does your program here?
>>
>>  José C.
>
>
>You are asking the _wrong_ question.  You should ask "How _long_ does it take
>your program to find this?"  Not "How deep does your program have to search
>to find this?"
>
>The two questions are _not_ the same thing.  12 plies to one program might
>take a year on another program.
>
>For Crafty, on my dual 2.8, this takes 12 plies and 42 seconds to find:
>
>               12    20.02   0.08   1. ... Bc2 2. Qe2 O-O 3. f4 Bxe5 4.
>                                    fxe5 Nfd5 5. Bd2 Nb6 6. Ne4 Qe7 7.
>                                    Bxb4 Qxb4 8. Qxc2 Nxc4
>               12    42.20  -0.24   1. ... Nxg4 2. Nxg4 Qh4 3. h3 h5 4.
>                                    Ne5 Bxh3 5. Qf3 Bxe5 6. dxe5 Bxf1 7.
>                                    Bxf1 <HT>
>               12->  42.20  -0.24   1. ... Nxg4 2. Nxg4 Qh4 3. h3 h5 4.
>                                    Ne5 Bxh3 5. Qf3 Bxe5 6. dxe5 Bxf1 7.
>                                    Bxf1 <HT> (s=2)
>               13     1:05     ++   1. ... Nxg4!!

  Yes, I know it.
  I wanted to show this position where different qsearch approaches make a big
difference in plies-to-solution. Of course, time is what finally matters in
regard to playing strength.
  But I'm experimenting with qsearch now, trying to make a conclusion about
which is better for me, a complex qsearch or a simple qsearch and more pruning
in regular search.
  Also, this position might help understand other programs, for example I could
try to guess if some comercial program does checks in qsearch or not.

  José C.



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