Author: Harald Lüßen
Date: 16:13:22 10/26/05
Go up one level in this thread
On October 26, 2005 at 06:58:41, Tord Romstad wrote:
>I have found the technique to work even better (especially in tactical
>positions) with the following enhancement: If, at the node directly
>following a reduction, the null move fails low, and the moving piece
>in the move that refuted the null move is the same as the moving piece
>in the reduced move, immediately cancel the reduced-depth search and
>re-search the move with full depth. The point is that in cases like
>this, the reduced depth move often contain some serious tactical
>threat, and deserves a deeper search.
I want to understand this. Let me try to explain it in my words
and pseudo code. I have left out everything else.
search(a,b,d) {
try nullmove
for moves M
r=0 but reduce late moves with r=1 (or fraction?)
do move
again:
search(-b,-a,d-1-r)
--> {
try nullmove
if it fails low because of move N
and M was reduced (M.r > 0)
and M.piece == N.piece
then return cancel_reason_tords_enhancement
for moves m
...
next move
}
<--
if r>0 and returned cancel_reason_tords_enhancement
r = 0
goto again
undo move
next move
}
In 'and M.piece == N.piece' is it important that it is
exactly the same piece or can it be the same piece-type?
Can you confirm this or correct me?
Harald
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