This is a known weakness in the eval engine. Bearing in against many checkers isn't handled too well.
Christian. On Wed, Jul 1, 2009 at 6:00 AM, Masanori Itikawa<spbackgam...@gmail.com> wrote: > Hi.all. > I find gnubg make strange evaluation in some positions. > GNU Backgammon Position ID: YAMHwHu2bR0EAA > Match ID : cInsABAAKAAA > +13-14-15-16-17-18------19-20-21-22-23-24-+ O: Staf1 > | X O | O | O | 1 point > | O | O | O | > | | O | | > | | O | | > | | | | > v| |BAR| | 7 point match (Cube: 1) > | | | | > | | | O | > | O X | | O | > | O X | | X X X X X O | Rolled 13 > | O X X | | X X X X X O | 5 points > +12-11-10--9--8--7-------6--5--4--3--2--1-+ X: othello > 1. Cubeful 2-ply 13/10 6/5 Eq.: +1.687 > 0.885 0.730 0.414 - 0.115 0.001 0.000 > 2-ply cubeful prune [world class] > 2. Cubeful 2-ply 8/7 6/3 Eq.: +1.686 ( -0.001) > 0.886 0.727 0.414 - 0.114 0.001 0.000 > 2-ply cubeful prune [world class] > 3. Cubeful 2-ply 6/5 6/3 Eq.: +1.674 ( -0.013) > 0.884 0.723 0.408 - 0.116 0.000 0.000 > 2-ply cubeful prune [world class] > 23. Cubeful 2-ply 6/3 5/4 Eq.: +1.440 ( -0.246) > 0.834 0.690 0.336 - 0.166 0.005 0.000 > 2-ply cubeful prune [world class] > 24. Cubeful 2-ply 8/5 7/6 Eq.: +1.418 ( -0.269) > 0.835 0.647 0.411 - 0.165 0.000 0.000 > 2-ply cubeful prune [world class] > My choice was 8/5 7/6. I do not insist that my choice is best, but 13/10 > 6/5 > and 8/7 6/3 are clearly not best. > > GNU Backgammon Position ID: YAMHwHe23RkEAA > Match ID : cAnzABAAKAAA > +13-14-15-16-17-18------19-20-21-22-23-24-+ O: Staf1 > | X O | O | O | 1 point > | O | O | O | > | | O | | > | | | | > | | | | > v| |BAR| | 7 point match (Cube: 1) > | | | O | > | | | O | > | O | | X X O | > | O X | | X X X X X O | Rolled 64 > | O X | | X X X X X O | 5 points > +12-11-10--9--8--7-------6--5--4--3--2--1-+ X: othello > 1. Cubeful 2-ply 8/2 6/2 Eq.: +1.494 > 0.849 0.675 0.351 - 0.151 0.000 0.000 > 2-ply cubeful prune [world class] > 2. Cubeful 2-ply 13/7 6/2 Eq.: +1.485 ( -0.009) > 0.847 0.669 0.358 - 0.153 0.000 0.000 > 2-ply cubeful prune [world class] > 3. Cubeful 2-ply 13/3 Eq.: +1.315 ( -0.179) > 0.812 0.619 0.358 - 0.188 0.000 0.000 > 2-ply cubeful prune [world class] > 4. Cubeful 2-ply 13/9 8/2 Eq.: +1.245 ( -0.249) > 0.798 0.607 0.355 - 0.202 0.000 0.000 > 2-ply cubeful prune [world class] > 5. Cubeful 2-ply 8/4 8/2 Eq.: +1.190 ( -0.304) > 0.780 0.593 0.345 - 0.220 0.000 0.000 > 2-ply cubeful prune [world class] > 6. Cubeful 2-ply 13/7 8/4 Eq.: +1.071 ( -0.423) > 0.755 0.556 0.349 - 0.245 0.000 0.000 > 2-ply cubeful prune [world class] > My choice was 13/7 8/4. Why is this move a super big blunder? > GNU Backgammon Position ID: YAMHwHe2uysAAA > Match ID : cInpABAAKAAA > +13-14-15-16-17-18------19-20-21-22-23-24-+ O: Staf1 > | O | O | O | 1 point > | O | O | O | > | | O | | > | | | | > | | | | > v| |BAR| | 7 point match (Cube: 1) > | | | O | > | | | O | > | O | | X X X O | > | O | | X X X X X O | Rolled 32 > | O X X | | X X X X X O | 5 points > +12-11-10--9--8--7-------6--5--4--3--2--1-+ X: othello > 1. Cubeful 2-ply 6/4 6/3 Eq.: +1.477 > 0.847 0.666 0.350 - 0.153 0.001 0.000 > 2-ply cubeful prune [world class] > 2. Cubeful 2-ply 5/3 5/2 Eq.: +1.430 ( -0.047) > 0.838 0.659 0.346 - 0.162 0.001 0.000 > 2-ply cubeful prune [world class] > 3. Cubeful 2-ply 6/3 4/2 Eq.: +1.421 ( -0.056) > 0.836 0.647 0.348 - 0.164 0.000 0.000 > 2-ply cubeful prune [world class] > 15. Cubeful 2-ply 8/6 5/2 Eq.: +1.071 ( -0.406) > 0.751 0.535 0.335 - 0.249 0.000 0.000 > 2-ply cubeful prune [world class] > 16. Cubeful 2-ply 8/3 Eq.: +0.923 ( -0.554) > 0.715 0.489 0.329 - 0.285 0.000 0.000 > 2-ply cubeful prune [world class] > My choice was 8/3. It may be not best, but It never be a super big blunder. > Why is 6/4 6/3 best??? > I analyzed my match by GNU Backgammon 0.90-mingw 20090625 on Windows xp sp3. > _______________________________________________ > Bug-gnubg mailing list > Bug-gnubg@gnu.org > http://lists.gnu.org/mailman/listinfo/bug-gnubg > >
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