XG vs gnubg analysis

[badgolferman]

I've recently started playing online at a site named Backgammon Galaxy.
The site claims to be powered by XG Gammon and it provides a 3-ply
analysis of every match.

When I download the move list and analyze it with gnubg set at Supremo
level it invariably always produces a lower analysis rating than the
website.

How does XG 3-ply compare to gnubg Supremo? What would be equivalent
levels?

[Timothy Chow]

Post by badgolferman
I've recently started playing online at a site named Backgammon Galaxy.
The site claims to be powered by XG Gammon and it provides a 3-ply
analysis of every match.
When I download the move list and analyze it with gnubg set at Supremo
level it invariably always produces a lower analysis rating than the
website.
How does XG 3-ply compare to gnubg Supremo? What would be equivalent
levels?

On a move-by-move basis, XG 3-ply and GNUBG supremo are very
similar. The trouble is that XG and GNU use different methods
for aggregating errors into an overall analysis rating, and
they also use definitions of the same words (e.g., "Expert").

For improving one's play, it's the move-by-move analysis that
really matters. My recommendation would be to ignore the
overall ratings and the labels such as "Expert" or "Advanced."

---
Tim Chow

[Axel Reichert]

Post by badgolferman
How does XG 3-ply compare to gnubg Supremo?

Any claimed deficiencies of GNU Backgammon's versus eXtreme Gammon's
playing strengths are in my opinion negligible when it comes to working
on your own level of play, see

https://www.bkgm.com/articles/Keith/DepreliBotComparison/index.html

Both programs are far better than world class players, so it is not due
to false analysis of one bot that the assessment ("Advanced", "Expert")
differs, but rather the totalling of errors and the thresholds used for
classification. Full ACK with Tim here. Please see also the comment of
Daniel Murphy on the page above for a nice tuning tip regarding GNU
Backgammon ("World Class" for cube decisions, "Grandmaster" for checker
play).

Axel

[badgolferman]

Post by Axel Reichert

Post by badgolferman
How does XG 3-ply compare to gnubg Supremo?

Any claimed deficiencies of GNU Backgammon's versus eXtreme Gammon's
playing strengths are in my opinion negligible when it comes to
working on your own level of play, see
https://www.bkgm.com/articles/Keith/DepreliBotComparison/index.html
Both programs are far better than world class players, so it is not
due to false analysis of one bot that the assessment ("Advanced",
"Expert") differs, but rather the totalling of errors and the
thresholds used for classification. Full ACK with Tim here. Please
see also the comment of Daniel Murphy on the page above for a nice
tuning tip regarding GNU Backgammon ("World Class" for cube
decisions, "Grandmaster" for checker play).
Axel

I am having trouble understanding what the gnubg analysis levels are.
For Checker Play and Cube decisions I see:
Beginner, Casual Play, Intermediate, Advanced, Expert, World Class,
Supremo, Grandmaster, 4-Ply, User Defined.

Which of these is 2-ply, 3-ply, etc? The article refers to the ply
levels. Also it claims you should not use odd-ply for cube decisions
and only use even-ply for those.

My version of gnubg is 1.06.002.

[Timothy Chow]

Post by badgolferman
I am having trouble understanding what the gnubg analysis levels are.
Beginner, Casual Play, Intermediate, Advanced, Expert, World Class,
Supremo, Grandmaster, 4-Ply, User Defined.
Which of these is 2-ply, 3-ply, etc? The article refers to the ply
levels. Also it claims you should not use odd-ply for cube decisions
and only use even-ply for those.

You can click on the "Advanced Settings" button to see exactly what
(for example) Supremo means. Note that XG and GNU use different
definitions of "ply" so that XG 3-ply corresponds to GNU 2-ply.

My recommendation would be to use use Supremo all the time and not
worry about it. If a specific play interests you and you want to
study it in more depth, then you can do a rollout.

---
Tim Chow

[Axel Reichert]

Post by badgolferman
Beginner, Casual Play, Intermediate, Advanced, Expert, World Class,
Supremo, Grandmaster, 4-Ply, User Defined.
Which of these is 2-ply, 3-ply, etc?

As Tim wrote, click on "Advanced Settings". The article "All about GNU
Backgammon" by Albert Silver will help understanding the details.

Axel

[Philippe Michel]

[...] see
https://www.bkgm.com/articles/Keith/DepreliBotComparison/index.html
[...]
see also the comment of Daniel Murphy on the page above for a nice
tuning tip regarding GNU Backgammon ("World Class" for cube
decisions, "Grandmaster" for checker play).

[...] Also it claims you should not use odd-ply for cube decisions
and only use even-ply for those.
My version of gnubg is 1.06.002.

Both tuning tip and claim are no longer relevant since 2013 and gnubg
1.00 (the article is older than that). The playing strength increases
consistently with higher plies, both for chequers and cube play.

With the current version there is only a minor irregularity between 2ply
and 3ply : 2ply makes less doubling errors than 3ply, but more take/pass
errors so its overall cube strength is lower anyway.

[Axel Reichert]

since 2013 and gnubg 1.00 (the article is older than that). The
playing strength increases consistently with higher plies, both for
chequers and cube play.

That is valuable info, thanks!

Axel