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Subject: Re: Pulsar misses mate in 6 with Null Move. whats up?

Author: Larry Griffiths

Date: 20:41:33 09/22/00

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On September 22, 2000 at 21:01:49, Mike Adams wrote:

>    I have done some modifications in pulsars mate detection which seems to
>help. to early to see how it affects icc ratings.  Pulsar will not try to get
>out of check necesarily in qsearch but it will return checkmate now rather than
>being allowed to pass on the move when in checkmate in qsearch. With this
>improvement pulsar avoides the mate with a depth 4 search without nullmove and
>depth 5 with null move.  This is a lot better than depth 7 it was before.
>     The position actually was a rook sack not a queen sack. The queen at issue
>was pulsar's meaning that pulsar could delay the mate by 2 moves if it gave up
>its queen otherwise it was mate in 3 after pulsar's bad move.  But your point
>probably applies just as well since a rook sack would probably have a similar
>affect to a queen sack on null move.   I think one additional modification that
>would help is that if pulsar searches depth 4 and all is dandy then it searches
>3 moves in depth 5 and gets the abort search command but all 3 moves on depht 5
>return checkmate for pulsar, pulsar should continue to search the current depth
>and use more than its alloted time in the hopes of finding its way out of the
>checkmate.  I noticed that depth 5 was a very slow search since its move
>ordering at the root was invalidated once it realized that its depht 1 2 3 and 4
>search results were no good.  So it may help to have more time for such
>dangerous positions.


Sounds like you are least having some luck with null move.
I tried to implement a NULL MOVE today and got up to 50% decrease in time on one
position, and another position took about 5 times longer.

Larry.



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