iterative deepening & a/b pruning

[Folkert van Heusden]

Hi,

When performing iterative deepening, why shouldn't I re-use the calculated alpha/beta of the previous iteration?
I googled this and found some people saying "don't do this, use -inf/+inf" but I don't understand why.


regards

[Ron Murawski]

Hi Folkert,

When you finish a search to an arbitrary depth, you have no alpha/beta bounds, you have an exact value -- let's call this value 'score'. I use (score-margin) as the new alpha and (score+margin) as the new beta. where 'margin' is somewhere between 15 to 50 centipawns.

Ron

[Folkert van Heusden]

When you finish a search to an arbitrary depth, you have no alpha/beta bounds, you have an exact value -- let's call this value 'score'. I use (score-margin) as the new alpha and (score+margin) as the new beta. where 'margin' is somewhere between 15 to 50 centipawns.

Ah indeed. I must experiment with this. Thanks!