Magnus Persson wrote:
Quoting Jason House <[EMAIL PROTECTED]>:
Does anyone have any data on just how optimistic or pessimistic the
results
would be? I'd like to use some heuristics that inherit winning
percentages
from a parent node to bias the expected winning percentage of the
children
nodes... and maybe pruning away portions of a search in a fixed depth
monte
carlo search with iterative deepening.
This is confusing to me. Are you asking how UCT behaves in order to
implement
something which is not UCT?
I'd say that I want to understand the nature of monte carlo
simulations... not specifically UCT. You are absolutely correct that
I'm trying to cook up something which is not UCT.
Anyway, UCT scores has the property that the score of a node changes
very slowly
when it is searched deep.
For my theoretical analysis, one unfortunate property of UCT is that
many playouts from a set starting position means that the search tree
gets expanded and that the measured winning rate is some kind of average
of elements deeper in the tree. My original post asked about "monte
carlo" in an attempt to avoid that issue.
But does this mean that sibling scores can be compared
to each other? I would hesitate here because the scores change as a
function of
the search. In difficult positions the scores for all good moves are
often
very similar. The scores often move up or down slowly together as
function of if
the position is good or not.
Actually, "the scores moving up or down slowly together as function of
if the position is good or not" is exactly the type of thing I'm trying
to gauge. Essentially, I'd like to predict the performance of an
unexplored branch based on available data. Not an attempt to prune it
away, but rather to figure out when exploration of those branches should
occur.
I attach an sgf file where i added the principal variation of Valkyria
after the
black opening move of the center point using 5 minutes of thinking
time. For
each move I give the winning percentage and the number of playouts
that passed
this node. For the second move of black I also give the winning
percentage of
all siblings. The imortant thing here is that many of those move are only
searched 1000 times whereas the few best move were searched 1000000
times, but
there is still not much of a difference in the actual scores.
Thanks! Taking a quick look, I see the following winning percentages
for the principle moves:
B: 54.3%
W: 46%
B: 54.6%
W: 46.3%
B: 54.7%
W: 47.6%
B: 54.9%
W: 47.0%
Looking at a single color, the winning percentage seems to shift by 0.2
to 0.4%... About what I'd expect to see. What confuses me though is how
to interpret the jump back and forth as the color changes (about 8%).
Are the percentages always the winning percentage for black? Or is it
the winning percentage for the color to move?
If it's the winning percentage for the color to move, it seems really
strange that it'd go up for both colors as the principle variation went on.
If it's the winning percentage for black, why does it vary so drastically?
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