Author: Andrew Dados
Date: 16:53:46 10/31/98
Go up one level in this thread
On October 31, 1998 at 16:45:01, Inmann Werner wrote:
>I have problems with "nearly mate" positions, where the opponent can do some
>checks, so the mate gets beyond the horizon.
>
>One Example (really interesting!)
>
>
>Position (LCTII CMB 01)
> xrxxxxkx
> xqxxbpxx
> xxxpxxpx
> xxpPxxxx
> PxNxxxxR
> xxPxxQPx
> xPxxxPKx
> xxxxxxxx
>
>Best: c4d6/e7d6/f3f6 white wins
>
>In depth 7 , my program should find the solution, but it does not! The problem
>is, that black can make checks to bring the mate beyond the horizon. At each
>check, I extend the search for 1 ply, but it is not enough.
>
>The computer thinks:
>C4d6/e7d6/f3f6/b7d5+/g2h2/d6g3+!!/h2g3/d5d3+/g3h2/g8f8/ no h4h8 and black
>"stands good"
>7 plys plus 3 plys the checks end up at 10!!
>
>This things really often happen, and I am reall unhappy with it. When I tried to
>extend at a check with 2 plys, this problem was solved very early. But the
>overall searchdepth goes dramatically down, so the program plays worse.
>On an attack, it is nearly always possible for the opponent to slow down the
>attack with "senseless", but forced moves.
>I thought about something like:
>This is a mate in 1, therefore don´t let you disturb with "senseless " moves.
>But I have no thought, how to implement such a thing.
>Suggestions?
>
>Werner
One solution I find acceptable is whenever you make null move generate all
checks at next ply even if null throws you to quiescence... that way null
returns 'being mated' score - and based on that you can extend your search
deeper...hopefully going beyond all delaying moves.
Andrew
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