Lc0 Evaluation Explanation

Discussion of anything and everything relating to chess playing software and machines.

Moderators: bob, hgm, Harvey Williamson

Forum rules
This textbox is used to restore diagrams posted with the [d] tag before the upgrade.
Hamster
Posts: 6
Joined: Sat May 25, 2013 4:38 pm
Location: Wien

Lc0 Evaluation Explanation

Post by Hamster » Thu Aug 29, 2019 3:30 pm

I have read the explanation of the Lc0 output on https://github.com/LeelaChessZero/lc0/w ... Chess-Zero
but I still do not understand it or I do not know how to get the most from it. As an example of the challenge I am facing see the below output from Arena. Why is Be2 the move that Lc0 selects? It is neither the one with the highest P nor Q nor Q+U nor V value.

Image

cma6
Posts: 145
Joined: Thu May 29, 2014 3:58 pm

Re: Lc0 Evaluation Explanation

Post by cma6 » Thu Aug 29, 2019 4:08 pm

" highest P nor Q nor Q+U nor V value."
Hamster, please excuse this lc0 newbie question: What is the meaning of "P", "Q", "Q+U", & "V"?

zullil
Posts: 5684
Joined: Mon Jan 08, 2007 11:31 pm
Location: PA USA
Full name: Louis Zulli

Re: Lc0 Evaluation Explanation

Post by zullil » Thu Aug 29, 2019 4:10 pm

cma6 wrote:
Thu Aug 29, 2019 4:08 pm
" highest P nor Q nor Q+U nor V value."
Hamster, please excuse this lc0 newbie question: What is the meaning of "P", "Q", "Q+U", & "V"?
Follow link in his post.

grahamj
Posts: 38
Joined: Thu Oct 11, 2018 12:26 pm
Full name: Graham Jones

Re: Lc0 Evaluation Explanation

Post by grahamj » Thu Aug 29, 2019 4:34 pm

LC0 chooses the move with the most visits. Searching the explanation for 'visits' may help.
Graham Jones, www.indriid.com

zullil
Posts: 5684
Joined: Mon Jan 08, 2007 11:31 pm
Location: PA USA
Full name: Louis Zulli

Re: Lc0 Evaluation Explanation

Post by zullil » Thu Aug 29, 2019 4:55 pm

grahamj wrote:
Thu Aug 29, 2019 4:34 pm
LC0 chooses the move with the most visits. Searching the explanation for 'visits' may help.
So, in the image posted above, Be2 is chosen based on N = 152?

Paloma
Posts: 860
Joined: Thu Dec 25, 2008 8:07 pm

Re: Lc0 Evaluation Explanation

Post by Paloma » Thu Aug 29, 2019 5:03 pm

zullil wrote:
Thu Aug 29, 2019 4:10 pm
cma6 wrote:
Thu Aug 29, 2019 4:08 pm
" highest P nor Q nor Q+U nor V value."
Hamster, please excuse this lc0 newbie question: What is the meaning of "P", "Q", "Q+U", & "V"?
Follow link in his post.
Which post?

zullil
Posts: 5684
Joined: Mon Jan 08, 2007 11:31 pm
Location: PA USA
Full name: Louis Zulli

Re: Lc0 Evaluation Explanation

Post by zullil » Thu Aug 29, 2019 5:09 pm

Paloma wrote:
Thu Aug 29, 2019 5:03 pm
zullil wrote:
Thu Aug 29, 2019 4:10 pm
cma6 wrote:
Thu Aug 29, 2019 4:08 pm
" highest P nor Q nor Q+U nor V value."
Hamster, please excuse this lc0 newbie question: What is the meaning of "P", "Q", "Q+U", & "V"?
Follow link in his post.
Which post?
Well, there's only one embedded link in this entire thread.

jp
Posts: 840
Joined: Mon Apr 23, 2018 5:54 am

Re: Lc0 Evaluation Explanation

Post by jp » Fri Aug 30, 2019 12:17 am

Hamster wrote:
Thu Aug 29, 2019 3:30 pm
Why is Be2 the move that Lc0 selects? It is neither the one with the highest P nor Q nor Q+U nor V value.
Do you mean it played Be2 after the screenshot?

It looks to me that it does have the highest Q+U, as well as the highest N, but the only one the list of moves is in order for is N (visits).

I don't know what the "(+7)" in the top line means or the "(712)".

Hamster
Posts: 6
Joined: Sat May 25, 2013 4:38 pm
Location: Wien

Re: Lc0 Evaluation Explanation

Post by Hamster » Fri Aug 30, 2019 8:23 pm

jp wrote:
Fri Aug 30, 2019 12:17 am
Hamster wrote:
Thu Aug 29, 2019 3:30 pm
Why is Be2 the move that Lc0 selects? It is neither the one with the highest P nor Q nor Q+U nor V value.
Do you mean it played Be2 after the screenshot?

It looks to me that it does have the highest Q+U, as well as the highest N, but the only one the list of moves is in order for is N (visits).

I don't know what the "(+7)" in the top line means or the "(712)".
You are right, Q+U is actually the highest.

If Lc0 chooses the move with the most visits what would be a useful interpretation of the other variables?
E.g. why not choose the average expected value of all playouts for a move (Q)?

cma6
Posts: 145
Joined: Thu May 29, 2014 3:58 pm

Re: Lc0 Evaluation Explanation

Post by cma6 » Fri Aug 30, 2019 9:13 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.

Post Reply