[Bug-gnubg] Re: race net: 0ply and 1ply

[Joseph Heled]

Moore, Dave wrote:
> The discontinuities at odd plys for gnubg have always seemed more than a bit
> strange to me.  I'm a much better computer scientist than backgammon player,
> but something just seems off there.  Alas, I have no spare time (only spare
> CPU cycles) to back this up with contributions to the source code!

I agree. I was as baffled as you, but now I have part of the answer. I am trying 
to write this down, but it is not easy explaining it (my writing skills are up 
to the task)
> Would this net perform even better using the new movefilter code being added
> to gnubg, which might let it "skip" over 1-ply pruning, thereby helping
> 2-ply even more?

This is the whole idea behind the movefilter. 2ply is stronger now, of that I am 
sure.

> To answer the actual question, I'd be fine with a better 0-ply to play
> against, and a better 2-ply for my analyses.
>
> Thanks!
> Dave
>
>
>
> > -----Original Message-----
> > From: Joseph Heled [mailto:address@hidden
> > Sent: Tuesday, November 26, 2002 1:56 PM
> > To: gnubg; Gary Wong; Øystein O Johansen; Joern Thyssen; 
> > Achim Mueller;
> > montgomery; max-d; Jim Segrave; Nardy Pillards; Ian Shaw; Steve J.
> > Baedke; Tore Saanum; MSquonk; Moore, Dave; Albert Silver; 
> > "Pål Schrader"
> > Subject: race net: 0ply and 1ply
> >
> >
> >
> > I now have a race net whose 0ply move error (as given by the 
> > race benchmark 
> > which you kindly helped to roll) is 62% of the current net. 
> > The 2ply error is 
> > 90% (i.e. 10% better). Alas, 1ply error is twice as large!
> >
> > This is a somewhat bizarre result. I think I know in part why 
> > and will try to 
> > solve this, but it seems that improving the 1ply will degrade 
> > the 0ply.
> >
> > This raises a theoretical question. would YOU rather use a 
> > net with better 0ply 
> > and 2ply, or a lesser one with a better 1ply?
> >
> > Personally, I never use 1ply anymore. I use 0ply for quick, 
> > 2ply for more 
> > quality, but I would like your opinion.
> >
> > -Joseph