Reaching Depth Level

[Vinson Hum]

Hi,

There's some confusion about this bullet: "If depth limit has been reached,
then evaluate the board position after making each move." and the
explanation and Fig. 3 of the handout. I am only concerned with the value of
".value" of the move returned here.

According to Fig. 3, at a depth of 2, White makes a move and Black makes a
move for a total of 2 moves, which means that at the depth limit, the value
of board should only be the value of these two moves (most online resources
of the minimax algorithm seems to do this, and I did this was as well).
However, the bullet mentioned above seems to imply that, for the above
example, White should make one more move before evaluating the board value,
which would mean that it is evaluating 3 moves.

So which is it?

Thank you,
Vinson Hum

[Alexander Smith]

Hi Vinson,

You are correct - there are two different interpretations of what to do
when the depth limit is reached. The interpretation we were expecting was
what is stated in the text of the handout. If you are counting tree nodes,
this has the effect of going one level past the depth limit. (If you are
counting the number of times a minimax calls itself recursively, you get
the right number.) We didn't realize that the description in the handout
might be misleading, and no one complained about this until yesterday. So,
since it's too late to post changes to the lab now, we will accept either
interpretation. This means that what some people consider a depth limit
of 5 will be a depth limit of 6 for other people.

Alexander

Post by Vinson Hum
Hi,
There's some confusion about this bullet: "If depth limit has been reached,
then evaluate the board position after making each move." and the
explanation and Fig. 3 of the handout. I am only concerned with the value of
".value" of the move returned here.
According to Fig. 3, at a depth of 2, White makes a move and Black makes a
move for a total of 2 moves, which means that at the depth limit, the value
of board should only be the value of these two moves (most online resources
of the minimax algorithm seems to do this, and I did this was as well).
However, the bullet mentioned above seems to imply that, for the above
example, White should make one more move before evaluating the board value,
which would mean that it is evaluating 3 moves.
So which is it?
Thank you,
Vinson Hum