GNU Backgammon

Forum Archive : GNU Backgammon

Match equity tables

From:   Raccoon
Date:   27 July 2005
Subject:   GNU Backgammon MET advice
Forum:   GammOnLine

The GNU Backgammon download currently includes 15 match equity tables.
Based on the efforts of many peopIe, reported primarily in the and forums, I would currently
recommend using any of three of these fifteen with GNU Backgammon:

1. Woolsey-Heinrich Table. This is probably still the most widely used
   table. I used to use this table with GNU Backgammon because it was
   the table I was using over the board. It was created by Kit Woolsey
   about 14 years ago by analyzing the thousand-plus tournament matches
   in Hal Heinrich's database. However, it is not as accurate as the
   newest computer generated tables, mainly because (1) insufficient
   data in the database for all match scores necessitated a "mishmash of
   empirical data, a program which was based on some assumptions which
   may not be sound, a lot of judgment, and some fudging" by Woolsey
   to come up with reasonable numbers for all scores, and (2)
   championship level tournament players play better now. Sharper play
   and cube action result, particularly, in a higher gammon rate. When
   the Woolsey table was made, a gammon rate of 20-21% was commonly
   accepted. The latest bot-generated data find a gammon rate of 26-27%.
   As a minor point, this table causes GNU Backgammon to make at least
   one obvious post-Crawford cube error, as happened in one game in GNU
   Backgammon's last confrontation with BG Blitz in a computer games

2. Snowie version 2.1 table. This table was introduced with the v2.1
   patch in July 1999 but is still used today by Snowie version 4. I
   started using this table with GNU even though I was still using the
   Woolsey table over the board, because (1) it was an improvement over
   the Woolsey table (I believe it assumes a gammon rate of 26%) and (2)
   using this table with GNU aided comparison of GNU and Snowie
   evaluations and rollouts by eliminating the difference in tables as a
   source of difference in results.

3. G11 Table (Zorba Table). This is the table I use now. It was
   generated by Robert-Jan Velduizen in 2003 and is solely based on
   recursive GNUBG full rollouts of the opening position (0-ply play, 2-
   ply 100%/25%) up to 9-away scores. It has a theoretical advantage
   over the Snowie table because it was generated by (a) cubeful play
   (b) according to score, with whatever effect that has at GG (Gammon
   Go) and GS (Gammon Save) scores (-2,1 and -1-2 Crawford and similar
   scores) particularly and consequent trickle-down effects on the
   entire match table.

Among other tables:

Zadeh: The Zadeh table, first published in 1977, is the default when you
  download GNU Backgammon, but users should change this immediately:
    Settings/Options/Match/Load, followed by Settings/Save Settings
  This default should be changed (to Woolsey or G11, probably); nobody
  uses Zadeh, and any of the latest good tables is a better choice.

Ortega: The Ortega table was generated by Antonio Ortega and Danny
  Kleinman by interpolating between Danny Kleinman's old match table and
  Woolsey's table in order to generate three-decimal match equities,
  which is useful for computer calculations, but there is no empirical
  reason to believe the table is accurate, and it has been superseded by
  newer tables.

Dunstan: The Dunstan table was generated with Gnubg 0.14 (2-Ply 50%
  Move, 2-Ply 33% Cube) rollouts but only through 5-away scores so far.
  This post shows how it differs from the G11 table.

Kazaross-Shaw: I believe that Neil Kazaross and Ian Shaw have stopped
  work on the Kazaross-Shaw table in favor of the G11 table, which
  Kazaross has endorsed.

Friedman: Roy Friedman's table from his 1989 book World Class Backgammon
  Move by Move (still recommended reading) is not included in the GNUBG
  download. The table initially enjoyed some popularity but was widely
  criticized for assuming a gammon rate of 36%. The bots have
  subsequently shown that this rate is much too high.

Jacobs-Trice and MEC26: The Jacobs-Trice and MEC26 tables are both good
  and do not differ much from the G11 table. In fact there is not much
  difference between any of the best tables, and the latest available
  data generated by having GNU Backgammon play itself using different
  tables found little difference in results between any of the best
  match tables. archives much discussion of match tables.
Woolsey's table may still be the best choice for most players over the
board because (1) it is easy to remember, (2) works with Neil's Numbers
[] and (3) a gammon rate of
20-21%% may be closer to what most players attain in actual play than
26-27%. Players interested in comparing match tables should pay
particular attention to 3-away and 4-away scores.

No claims for originality here, but browsing through I thought we
might be due for a summary.
Did you find the information in this article useful?          

Do you have any comments you'd like to add?     


GNU Backgammon

Analyzing GamesGrid matches  (Roy Passfield, Dec 2001) 
Batch analysis tool  (Øystein Johansen, June 2004)  [GammOnLine forum]
Cache size  (Ned Cross+, Mar 2004)  [GammOnLine forum]
Compiling for Windows  (Øystein Johansen, Jan 2002) 
Edit mode removing checker from bar  (Scott Steiner+, May 2003) 
Entering an annotated match  (Albert Silver, Dec 2003)  [GammOnLine forum]
Error rates: Gnu vs. Snowie  (Raccoon, Mar 2006)  [GammOnLine forum]
Even-ply/odd-ply effect  (Raccoon, Nov 2004) 
Even-ply/odd-ply effect  (Tom Keith+, Oct 2003) 
Even-ply/odd-ply effect  (Scott Steiner+, Dec 2002) 
Filter settings  (Robert-Jan Veldhuizen, Nov 2004)  [GammOnLine forum]
Gnu 0.13 versus Jellyfish and Snowie  (Torsten Schoop, Aug 2003) 
Gnu 0.13 vs. Snowie 4  (Albert Silver, June 2003) 
Gnu 0.14 vs. Jellyfish  (Michael Howard+, July 2003) 
Gnu versus Snowie and Jellyfish  (Michael Depreli, Oct 2005) 
How luck factor is calculated  (Gregg Cattanach, Aug 2002) 
How rollouts work  (Gary Wong, July 1999) 
How to enter an illegal move  (Øystein Johansen, Aug 2003)  [GammOnLine forum]
Importing .gam files  (PAR+, Mar 2005) 
Importing PartyGammon matches  (rew+, July 2006) 
Improving your game using GnuBG  (D.U.G.+, Nov 2002) 
Installing on Windows  (maareyes, Oct 2001) 
Interpreting JSD's  (Adrian Wright+, Feb 2005)  [GammOnLine forum]
JSD's and confidence intervals  (Daniel Murphy+, Jan 2005) 
Logging rollouts  (Øystein Johansen, Oct 2004)  [GammOnLine forum]
Luck rate  (Kees van den Doel+, May 2002) 
MWC versus Equity (EMG)  (Ken+, Apr 2005)  [GammOnLine forum]
Manually entering first roll  (Andreas Graf+, Apr 2005) 
Match equity tables  (Raccoon, July 2005)  [GammOnLine forum]
Personal reflections  (Louis Nardy Pillards, Sept 2002) 
Playing two computers against each other  (Stanley E. Richards+, Mar 2008)  [GammOnLine forum]
Python scripting  (Øystein Johansen+, Nov 2004) 
Quasi-random dice in rollouts  (Ian Shaw, Mar 2004)  [GammOnLine forum]
Question marks in game list  (Jim Segrave, July 2005) 
Questions and answers  (Jim Segrave+, Jan 2003) 
Questions and answers  (Jørn Thyssen, Aug 2002) 
Restarting a rollout with different settings  (Jim Segrave, Apr 2005)  [GammOnLine forum]
Restarting a rollout with different settings  (Robert-Jan Veldhuizen, Apr 2004)  [GammOnLine forum]
Rollout settings  (geoff arnold+, Apr 2007) 
Rollout settings  (Stick+, Nov 2005)  [GammOnLine forum]
Rollout settings  (Robert-Jan Veldhuizen, Mar 2004)  [GammOnLine forum]
Rollout settings  (Ian Dunstan, Aug 2003)  [GammOnLine forum]
Rollout settings for the impatient  (Robert-Jan Veldhuizen, June 2004)  [GammOnLine forum]
Running rollouts in background  (Bruce+, Apr 2004)  [GammOnLine forum]
Saving rollout results from command-line interface  (Jeremy Bagai+, Apr 2006)  [GammOnLine forum]
Saving rollouts  (Mislav Radica+, May 2006)  [GammOnLine forum]
Setting GnuBG's playing strength  (JP White, Sept 2001) 
Setting skill level  (Jim Segrave, Apr 2004) 
Setting up and saving a rollout  (Albert Silver, Dec 2003)  [GammOnLine forum]
What's GNU?  (Gary Wong, Oct 2001) 
Which player is player 0?  (Neil Kazaross+, Oct 2004)  [GammOnLine forum]

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