Author: José Carlos
Date: 01:20:02 05/13/04
Go up one level in this thread
On May 13, 2004 at 03:35:00, Daniel Shawul wrote:
>Hello
>
>My search is fail soft(i return the actual score)
>when i fail high at the root i widen the window by 3 pawns (300).
>
> if(score<=r_alpha)
> {
> r_beta=r_alpha;
> r_alpha=score-300; //r_alpha = -MATESCORE;
> }
> else if(score>=r_beta)
> {
> r_alpha=r_beta;
> r_beta=score + 300; //r_beta = MATESCORE;
> }
>If the search fail's high at 1.75 score but the real score was 10
>i get a score of 4.75 (1.75 + 3) in the next iteration. Why? my search is fail
>soft and the score returned should be independent of beta. If i change the 200
>to 300,score returned is 4.75??
Are you sure you're doing fail soft? I mean, you need some extra logic, like
starting off with -INFINITE in alpha nodes and increase the best score even in
fail lows. You also need to make sure of returning true bounds in qsearch. Also,
if you do some kind of forward prunning depeding on alpha and beta you won't be
able to return true scores.
José C.
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