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Subject: Re: Mate in 7 moves - diagram

Author: Bernhard Bauer

Date: 00:08:25 09/29/00

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On September 28, 2000 at 10:18:53, Dieter Buerssner wrote:

>On September 28, 2000 at 04:26:54, Bernhard Bauer wrote:
>[much snipped]
>>My modification has also to do with null move, but I do another change.
>>Instead of the original statement in search.c
>>if (do_null && !tree->in_check[ply] && pieces
>>                                    && (pieces>5 || depth<421)) {
>>I use the following statement
>>if (do_null && !tree->in_check[ply] && pieces>0 && depth>60 &&
>>                                    && (pieces>9 || depth>301) ) {
>This is interesting. The original Crafty code uses null move at the leaves of
>the tree, when close to the endgame. Your code uses null move at at the front of
>the tree. Has this shown to be better in test suites or in games?
>Also, you don't allow null moves at the last ply. Does this reach higher depth
>with the same node count?
>-- Dieter

For many pieces (pieces>5) the original Crafty code will always use null move.
I don't use null move for the first ply hoping to get a better move ordering.
If only a few pieces remain I don't do null move for the first 5 plies.
I don't know if this plays better as I mostly use Crafty for analysis, but I do
some tests to overcome some shortcomings of Crafty.
Kind regards

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