I tried a little experiment on this: a 10-hidden-node network with a single probability-of-win output, but two setups. The first doesn't have a "whose turn is it" input and doesn't add any symmetry constraints. The second has the extra inputs for the turn and makes the symmetry constraint I described.
I trained them in parallel and benchmarked them against pub eval and against each other. The symmetric case performed a little better: it trained more quickly, did better against pub eval, and was on par or a little better than the other case when playing head to head. Details and data here: http://compgammon.blogspot.com/2011/12/testing-value-of-symmetry-constraint.html Of course not conclusive with such a simple setup, but kind of suggestive anyways. On Dec 10, 2011, at 2:22 PM, Mark Higgins wrote: > Thx! Makes sense. Though I wonder if adding back in the "whose move is it" > input and reducing the hidden->output weights by half ends up as a net > benefit for training. Maybe I'll test it out. > > > > On Dec 10, 2011, at 2:06 PM, Frank Berger <fr...@bgblitz.com> wrote: > >> Hi Mark, >> >>> If I take a given board and translate the position into the inputs and then >>> evaluate the network, it gives me a probability of win. If I then flip the >>> board's perspective (ie white vs black) and do the same, I get another >>> probability of win. Those two probabilities should sum to 1, since one or >>> the other player must win (or equivalently, the probability of white >>> winning = probability of black losing = 1 - probability of black winning). >> >> >> I assume your assumption is wrong. IIRC in an earlier paper there was an >> input to indicate who's on. It is much simpler to present the position from >> the point of the moving player, because the net has to learn less. I'm not >> that familiar with the gnubg code, but I think they do it in this way, so >> you can't just turn the perspective. >> >> ciao >> Frank >> _______________________________________________ >> Bug-gnubg mailing list >> Bug-gnubg@gnu.org >> https://lists.gnu.org/mailman/listinfo/bug-gnubg _______________________________________________ Bug-gnubg mailing list Bug-gnubg@gnu.org https://lists.gnu.org/mailman/listinfo/bug-gnubg