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Re: computer-go: [Question] Nullmove

For my program, I don't do a NULL move, but basically the equivelant: I
analyze the board for both white and black (assume the computer is white).
Then I analyze the best white moves for whether or not they help, and (more
importantly) whether they need to be done now (can an attack on a group or
defense wait?). If everything in white's best moves indicates that waiting
is a viable option, I look at black's (the player's) best moves. Perhaps
this next statement is that of a very inexperienced (13k) player, but I have
the program assume that black's best move is white's best defense:

12345
.....a
..X..b
.XOX.c
.....d

Example: Black's best move is d3 (according to my program), so that would by
white's best defense.

Well, that's my take on NULL move.

Jeff


Xu, Mousheng wrote:
I have been trying to understand the lengthy discussions about nullmove
for a few days, but still have no clue why you guys are interested in
it. So here comes my question.

In a game tree, because of the limitation of computer power, usually you
decide to stop while the width or the depth of the tree reaches a
certain number (say, 3 nodes wide, 4 nodes deep). Since the depth of the
terminal nodes are the same in 99% cases, the terminal evaluation can be
assumed to be equally fair to each node. If I understand correctly, you
guys are talking about to take nullmove into consideration while
evaluating the terminal node so that the evaluation is closer to
reality. But why do you care about the absolute values of your
evaluation? You only care about the relative order of the evaluations,
right?

I am sure I am missing something.

Thanks.

-- Mousheng Xu

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