I'm actually a newcomer to NN engines, so I'm still learning. I believe P is the probability that the move is the right one to play in this position, based solely on the output of the net, with no additional searching/roll outs. So the P values give an initial suggestion of which moves are likely good ones, and so worthy of further analysis. There is a discussion of these various variables here:cma6 wrote: ↑Fri Aug 30, 2019 11:13 pm Zulli:
Do you know the meaning of these terms: "P", "Q", "Q+U", & "V"?
I am guessing that V = visits. But, as pointed out, Be2 does not have the highest V value of all the moves shown. Or does the lc0 site have an explanation of the parameters, since when I searched here for "visits", it gave me no new information.
I found the meaning of the "(+7)", etc. It's "how many visits are processed by other threads when this is printed".
Code: Select all
e2e4 (123) N: 329 (+ 4) (V: -12.34%) (P:38.12%) (Q: -0.2325) (U: 0.2394) (Q+U: 0.0069)
^ ^ ^ ^ ^ ^ ^ ^ ^
| | | | | | | | Q+U, see below
| | | | | | | U from PUCT formula,
| | | | | | | see below.
| | | | | | Average value of V in a subtree
| | | | | Probability of this move, from NN, 0%..100%
| | | | Expected outcome for this position, directly from NN, -100%..100%
| | | How many visits are processed by other threads when this is printed.
| | Number of visits. The move with maximum visits is chosen for play.
Move |
Internal move id (for debugging)
* U = P * Cpuct * sqrt(sum of N of all moves) / (N + 1)
CPuct is a search parameter, can be changed with a command line flag.
* The move with largest Q+U will be visited next
* The move with the highest N is played when search is stopped
