crafty question (Bob)

[Cardoso]

Hi,
how did you fixed the backward moves in the killer array due to color flipping back and forward in version 23.3 ?

thanks in advance,
Alvaro

[bob]

Hi,
how did you fixed the backward moves in the killer array due to color flipping back and forward in version 23.3 ?

thanks in advance,
Alvaro

I simply improved the "legality checker" code. This is only an issue when I have no move to ponder and start a "puzzling search" to find a ponder move. Since I flip sides, now the killers have moves for opposite sides. By checking to see if a pawn is moving backward, the problem goes away...

[hgm]

Wouldn't it be better to simply shift the killer array one entry when you start a seach for the opposite color? That seems very cheap,and you would not have to do anything in search.

[bob]

Wouldn't it be better to simply shift the killer array one entry when you start a seach for the opposite color? That seems very cheap,and you would not have to do anything in search.

Perhaps. But there are several ways to "change sides" and I elected to keep things simple. Analyze mode is one example, hunting for a move to ponder is another. And there are probably others I have forgotten. Was easier to just make the "legality check" a bit more accurate.