It is important to know about potential blind spots introduced by pseudo-eye variations, or any other rules.
Borrowing from Eric S Raymond, the more eyes inspecting the ideas, the shallower the bugs. Terry McIntyre <[EMAIL PROTECTED]> We must stop dressing up the slaughter of foreigners as a great national cause. -- Sheldon Richman ----- Original Message ---- > From: Claus Reinke <[EMAIL PROTECTED]> > To: [email protected] > Sent: Friday, October 10, 2008 1:54:48 PM > Subject: [computer-go] pseudo eye variations for playouts > > Thanks everyone for the answers regarding playout terminations. I still > have my suspicions regarding how artificial game length bounds affect > the position evaluation (I'd expect the values to fluctuate with length, > so arbitrary bounds would result in arbitrary differences). > > For the moment, however, I'd like to focus on the variations wrt > pseudo-eyes (positions not to be filled during playouts). All of these > are known to be wrong in some cases, the main argument in favour of > pseudo-eyes being efficiency. > > Since ruling out fill-ins introduces not only biases, but actual blind spots > into the playouts, something even heavy playouts otherwise try to avoid > (they prioritize "good" moves instead of eliminating "bad" moves) it is > important that the definition of pseudo-eyes errs on the safe side ("safe" > here meaning random play - any move is possible): they may permit > erroneous fill-ins, but must not rule out necessary fill-ins (only definitely > bad fill-ins may be ruled out). > > Within that constraint, the goal is to rule out as many bad fill-ins as > possible without ruling out any good fill-ins. And all three variations > listed earlier (Gobble, Olga, Oleg) > > http://computer-go.org/pipermail/computer-go/2008-October/016549.html > > have their issues with that. For instance, consider the following position: > > ( > ; > FF[1] > GM[1] > SZ[19] > AP[Jago:Version 5.0] > AB[ji][kj][jk][ij][jl][hj][jh][lj][jg][kf][ke][le][me][ne][of][og][oh][oi][ni][mj][nf][kg][nj][jm][jn][jo][jp][ip][hp][gp][fp][fo][fn][fm][fl][fk][fj][gj][gi][gh][hg][ig][ok][gf][pl][fe] > AW[ki][kh][li][lg][mh][lf][mf][ng][nh][kk][lk][kl][mi][mk][nk][ik][hk][gk][gl][gm][gn][il][im][in][io][go][hm][ho][jd][kd][ld][md][nd][od][pe][pf][ph][pg][pi][pj][ei][ej][ek][el][em][en][eo][ep][eq][fq][gq][hq][iq][jq][kq][ko][kp][kn][km][oj][ii][fi][fh][fg][gg][hf][if][jf][je][ih][oe] > C[black to move. > > Gobble: 'a' is not an eye => fill it and die > > Olga: 'a' is an eye, but would cease to be if 'b' was white > > Oleg: 'a' is not an eye, but would be if 'b' was black] > L[jj][hh][nk][oj] > GN[playout-eyes] > ) > > If I set this up correctly, the black center group is "unconditionally" alive, > even if it was white's turn, while playouts with Gobble-style pseudo-eyes > will rate it as unconditionally dead (and hence the white strings 'c' and 'd' > as unconditionally alive, independent of conditions on the outside). Playouts > with Olga-style pseudo-eyes would fare better, but would be fooled into > considering fill-in at 'a' after white 'b'. Playouts with Oleg-style > pseudo-eyes > have a chance of finding the black group alive, in case of black 'b' first. > > Did I set this up right? And why does no-one else seem worried about it?-) > > Claus > > PS In case the sgf-labelling isn't standard, 'a' is K10/center, 'b' is H12. > > > > > _______________________________________________ > computer-go mailing list > [email protected] > http://www.computer-go.org/mailman/listinfo/computer-go/ _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
