BGonline.org Forums

Why do bots have an even/odd effect?

Posted By: Tom Keith
Date: Thursday, 13 August 2009, at 1:54 p.m.

In Response To: Why do bots have an even/odd effect? (playBunny)

Hi pB,

I'm still not sure why there would be enough difference in these to create an odd/even play effect. It's true that these are markedly different positions but I would imagine that in training the nets for one, the other would be encountered and trained for to an equal degree as you can't play one without the other. Thus the equities should be complementary.

If a bot is trained to give accurate absolute equities, then this is true (I would think). But if a bot is trained only to give accurate relative equities*, there is no guarantee that the absolute equities are at all close to being accurate. The even/odd effect is the difference in absolute equity viewing the board from one side as compared to viewing it from the other side.

["Accurate relative equities" means that the NN is good at ordering from best to worst positions that are similar to one another, for example, positions that result from different ways of playing a particular roll.]

If you are interested in knowing more about how GnuBG was trained, you might enjoy this article by Joseph Haled: http://pages.quicksilver.net.nz/pepe/ngb/index.html

Tom

Messages In This Thread

• Falafel to play 41
  Stick -- Monday, 10 August 2009, at 3:33 a.m.
  • Falafel to play 41
    Havard Raddum -- Monday, 10 August 2009, at 6:31 a.m.
  • Falafel to play 41
    sonrik -- Monday, 10 August 2009, at 6:51 a.m.
  • Falafel to play 41
    mamabear -- Monday, 10 August 2009, at 1:06 p.m.
  • Falafel to play 41
    Keene -- Monday, 10 August 2009, at 3:51 p.m.
  • Falafel to play 41
    garyo -- Monday, 10 August 2009, at 4:37 p.m.
  • Falafel to play 41
    Gustavo Goldfarb -- Monday, 10 August 2009, at 4:56 p.m.
  • Falafel to play 41
    Fabrice Liardet -- Monday, 10 August 2009, at 8:01 p.m.
  • Rollout
    Stick -- Tuesday, 11 August 2009, at 1:21 a.m.
    • Rollout
      neilkaz -- Tuesday, 11 August 2009, at 3:22 a.m.
    • Rollout
      ScottyK -- Tuesday, 11 August 2009, at 1:57 p.m.
      • Re: GNU 4 ply..GV etc
        neilkaz -- Tuesday, 11 August 2009, at 3:07 p.m.
      • Plies again
        Matt Cohn-Geier -- Tuesday, 11 August 2009, at 4:45 p.m.
        • Plies again
          Chuck Bower -- Tuesday, 11 August 2009, at 8:43 p.m.
          • Plies again
            Matt Cohn-Geier -- Wednesday, 12 August 2009, at 3:26 a.m.
            • Plies again
              Chuck Bower -- Wednesday, 12 August 2009, at 1:48 p.m.
        • Plies again
          ScottyK -- Tuesday, 11 August 2009, at 9:28 p.m.
          • Plies again
            Keene -- Tuesday, 11 August 2009, at 9:59 p.m.
            • Plies again
              ScottyK -- Tuesday, 11 August 2009, at 10:23 p.m.
        • Plies again
          playBunny -- Tuesday, 11 August 2009, at 11:15 p.m.
          • Plies again
            MaX -- Wednesday, 12 August 2009, at 11:29 a.m.
            • Plies again
              playBunny -- Wednesday, 12 August 2009, at 1:15 p.m.
              • Why do bots have an even/odd effect?
                Tom Keith -- Wednesday, 12 August 2009, at 2:11 p.m.
                • Why do bots have an even/odd effect?
                  MaX -- Wednesday, 12 August 2009, at 3:27 p.m.
                • Why do bots have an even/odd effect?
                  playBunny -- Wednesday, 12 August 2009, at 7:51 p.m.
                  • Why do bots have an even/odd effect?
                    Tom Keith -- Thursday, 13 August 2009, at 1:54 p.m.
                    • Why do bots have an even/odd effect?
                      playBunny -- Thursday, 13 August 2009, at 4:50 p.m.
                  • Why do bots have an even/odd effect?
                    MaX -- Saturday, 15 August 2009, at 8:53 p.m.
                    • Why do bots have an even/odd effect?
                      Tom Keith -- Monday, 17 August 2009, at 11:16 p.m.
                      • Why do bots have an even/odd effect?
                        playBunny -- Tuesday, 18 August 2009, at 12:59 a.m.
                        • Why do bots have an even/odd effect?
                          Tom Keith -- Tuesday, 18 August 2009, at 12:44 p.m.
                          • Why do bots have an even/odd effect?
                            playBunny -- Tuesday, 18 August 2009, at 4:39 p.m.
                            • Why do bots have an even/odd effect?
                              Tom Keith -- Tuesday, 18 August 2009, at 5:45 p.m.
                      • Why do bots have an even/odd effect?
                        Maik Stiebler -- Tuesday, 18 August 2009, at 6:14 a.m.
                        • Why do bots have an even/odd effect?
                          Tom Keith -- Tuesday, 18 August 2009, at 12:46 p.m.
                      • Why do bots have an even/odd effect?
                        MaX -- Thursday, 20 August 2009, at 2:54 p.m.
                      • Gnubg odd/even effect extreme example ?
                        MaX -- Friday, 21 August 2009, at 2:19 p.m.
                        • Gnubg odd/even effect extreme example ?
                          Gregg Cattanach -- Friday, 21 August 2009, at 7:24 p.m.
                        • Gnubg odd/even effect extreme example ?
                          Frank Berger -- Saturday, 22 August 2009, at 6:02 a.m.
      • Rollout
        Rich Munitz -- Tuesday, 11 August 2009, at 7:35 p.m.
        • Rollout
          ScottyK -- Tuesday, 11 August 2009, at 9:22 p.m.
          • Rollout
            Rich Munitz -- Wednesday, 12 August 2009, at 12:14 a.m.
            • Rollout
              ScottyK -- Wednesday, 12 August 2009, at 1:23 a.m.
          • Rollout
            Chuck Bower -- Wednesday, 12 August 2009, at 1:52 p.m.
  • Falafel to play 41
    Toppace -- Wednesday, 12 August 2009, at 6:20 p.m.
    • Falafel to play 41
      Keene -- Wednesday, 12 August 2009, at 7:29 p.m.