Computer Chess Club Archives




Subject: Fast BB move generation

Author: Bas Hamstra

Date: 05:57:49 05/08/00

It seems that some (i.e. DarkThought) rotated BB programs use 1-at-a-time
movegeneration, that generate just the best MVV/LVA move. I don't understand how
they can make this work.

Idea being that in many cases you only need the first capture, thus saving a lot
of work. On average.

However for this to make sense, it should cost you AT LEAST fewer ticks to
generate the 1 best capture than to generate them all and do a sort.

According to some quick & dirty measuring, in 75% of the cases the best capture
is a knight- or pawncapture. So you should be able to generate these (1 by 1)
faster than doing all captures.

The point: I see NO way to fetch the 1 best capture substantially faster than
doing all captures. So how do you do it?

a) Doing for each enemy piece an AttackTo is very expensive
b) Building a combined attackmap and finding the highest attacked victim
   is basically the same as doing all captures.

So: what am I overlooking here?

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