Author: Robert Hyatt
Date: 07:36:46 12/22/00
Go up one level in this thread
On December 22, 2000 at 03:11:32, David Rasmussen wrote:
>On December 21, 2000 at 21:45:52, Robert Hyatt wrote:
>
>>On December 21, 2000 at 21:29:02, Dann Corbit wrote:
>>
>>>Has anyone tried this:
>>>
>>>Exhaustive search (NO Null move pruning) out to some arbitrary ply from the root
>>>{e.g. ply 5} and then increasingly aggressive Null move pruning forward from
>>>there [perhaps with a linear increase in aggressiveness out to some level]
>>>?
>>
>>
>>I do something similar. In endgames where there is less than a queen, but
>>one side still has pieces, I don't do null move for the first N plies of
>>the search.
>>
>
>I can't see that anywhere in your code. Help! :)
>
if (do_null && !tree->in_check[ply] && pieces && (pieces>5 || depth<421)) {
^^^^^^^^^^^^^^^^^^^^^
There (in search.c). If there is more than a rook on the board, then it always
does normal null-move search. If there is a rook or less, then null move is
only done in the final 7 plies, so that the first part of the tree has no
null-move failures...
(depth < 421 is the same thing as saying if depth <= 7 plies, because a ply
is 60 units).
>>I also do a graduated null-move search, where R=3 for positions near the root,
>>and R=2 for positions near the leaf positions. I think doing the inverse is
>>wrong, as you will hide too much by letting null-move collapse the last few
>>plies into a simple quiescence search...
>
>This I can see.
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