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Subject: Re: Q: null move

Author: Andrew Williams

Date: 10:57:17 08/03/99

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On August 03, 1999 at 13:41:16, Scott Gasch wrote:


Hi Scott,


>After some fixes, here are the numbers.  However, it still does not see the
>"right" move (pawn push to d6)?
>

The move is actually 1. e6, but mine needs to get to depth 9 to find it and
see the point of it. Before it sees e6, it fiddles about with 1. f3 or 1.h3
or 1. Rae1 etc etc


>1) val=0, delta=65536, score=50, nodes: 77377
>    1.1 sec -- f2f3 g4h6
>3) val=50, delta=250, score=50, nodes: 150056
>    2.1 sec -- f2f3 g4h6 g5e7
>4) val=50, delta=125, score=50, nodes: 3474041
>    50.4 sec -- f2f3 g4h6 g5e7 d7e7
> (TIMER)
>
>  internal nodes..................................7367
>  leaf nodes......................................0
>  qeval nodes.....................................4095107 (2661756 cuts)
>  depth nodes.....................................0
>                                                -------

This seems a very odd balance between internal nodes and qeval nodes.
What sort of pruning are you doing in your qsearch? (FYI to get to depth
4, I use a total of about 4500 nodes, ~750 in the main search and ~3750
in the qsearch.


>  total nodes.....................................4102474
>  time (sec)......................................60.10
>  rate (nodes/sec)................................68258
>
>  positions added to hash.........................6650
>  hash lookup hits................................717 (14 exact)
>  hash lookup misses..............................6650
>  hash efficiency percentage......................9.73%
>
>  null move successes.............................510
>  null move failures..............................412
>  null move success rate..........................55.31%
>

Attempting null move 922 times still seems low. Even at low depths, mine
tries the null move in 75% of non-quiesce nodes. In what circumstances do
you not use null move?

>  pawn hash hits..................................2061097
>  pawn hash misses................................107542
>  pawn hash success rate..........................95.04%



Cheers

Andrew



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