Possible bug in update_values?

[gaffney2010]

The code in update_values does:

...
self.visit_count += 1

self.q_value += leaf_value / self.visit_count
...

So that if you call this three times with leaf_value 3, 4, 5, then q_value will be 3/1 + 4/2 + 5/3, since the visit_count gets updated while we increment q_value. This seems to contradict the description in the book as the average of leaf node values. (If I've understood correctly.)

[yliu000]

I got same question.

[pocca2048]

me too.
I believe this should be:

self.q_value = (self.q_value * (self.visit_count-1) + leaf_value) / self.visit_count