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Subject: Re: Can your prog solve this -- results

Author: Vincent Diepeveen

Date: 17:40:13 02/18/99

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On February 18, 1999 at 16:43:51, Robert Hyatt wrote:

>On February 18, 1999 at 16:30:01, Will Singleton wrote:
>
>>
>>Here are the results:
>>
>>                    <=5    6     7     8     >=9
>>
>>Fritz 5.32          dxe5   dxe5  dxe5  dxe5  dxe5
>>Hiarcs 6            Nh4    Nh4   Be3   Be3   Be3
>>MacChess 4          dxe5   dxe5  dxe5  dxe5  Bc1
>>Crafty 16.5         dxe5   Bc1   Bc1   Bc1   Bc1
>>Amateur 0.91        dxe5   dxe5  dxe5  dxe5  Bc1
>>PostModernist 0.9   Nh4    dxe5  dxe5  Bc1   Bc1
>>EXchess 2.5x        Bc1    Bd2   Bc1   Be3   Be3
>>LambChop 7.x        Bc1    dxe5  Bc1   Bc1   Bc1
>>Gromit 1.2?         ---    ---   ---   dxe5  Nh4
>>Robertson 0.0       Bc1    Bc1   dxe5  dxe5  dxe5
>>Ferret              Bc1 or dxe5, whatever
>>InmiChess           ---    ---   Nh4   Nh4   Nh4
>>Diep                classified (private email :), but it wasn't dxe5)

It is not classified :)

>>
>>Thanks for all your responses, we have some interesting results.
>>A couple of issues here -- the first is that the position
>>occurred in a blitz game, so only about 10 seconds was available
>>to move.  As it turns out, the position is already bad, -1 or
>>so (as Bruce says, White is hosed), so there's no real good move
>>-- but short term, there is a wide variety of opinion between
>>the various programs.  This has significance for blitz play,
>>especially considering that dxe5 is probably the best move!
>>
>>I thought it might be interesting to analyze the reasons for the
>>diversity of move selection.  Some programs see deeper for a
>>given ply depth, of course.  Do they pay a price for this by
>>having to take longer to iterate to a given ply?  Or does the
>>deeper search (more extensions) result in better ordering, which
>>causes the desired ply to be reached even sooner?
>>
>>The position is fairly complex, and I would expect lots of
>>extension triggers.  For example, Hiarcs is known (I think) to
>>extend quite a bit.  I ran this with Hiarcs 6, and it never
>>considers dxe5 (as the best move) through many minutes of
>>searching.  But after dxe5 a4 Qxa4 fxe5 Qxc4 etc, it has a
>>better eval for white than it did with any alternative to dxe5
>>originally.  So it looks like it missed what it later considers
>>to be the best move, which is dxe5!
>>
>>Bc1 is worse (or no better) because of a4 Qb4 Re6 Nh4 Rb6 ...
>>Be3 is worse (or no better) because of exd4 cxd4 Re6 Re3 Rb6 ...
>>
>>Maybe Bob has a bug. :)  In both outputs I received, Crafty
>>doesn't see the proper continuation after dxe5.  And I believe
>>Dann said that it may have switched back after a long think.
>>
>
>I don't think I have a 'bug' but we may have differences...  IE Dan wasn't
>using the current 16.6 code, which is significantly different in the eval
>area.  On the above test (the data I sent came from my notebook) it liked
>Bc1 until the last ply I gave you when it changed to Be3 and stuck there.
>
>I am not sure de loses...  you may be lost already...
>
>
>
>
>>Interestingly, Jim Walker says that Fritz 5.32 prefers dxe5
>>throughout a long search.  I would like to see the pv output on
>>that.  Why does Fritz remain constant on what is probably the
>>best move, while others are all over the lot?
>>
>>Will



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