Hi all, I saw some squiffy behaviour in the Race Formulas - Keith Count feature, which did not agree with XG's conclusion.
Please see short video here: https://fy0o.short.gy/wj_cy_keith_count_bug_gnubg XGID=-ABBA-C------------e--aaa-:1:1:1:00:0:0:0:3:10 GNUbg FR8AANpyAAAAAA:UQlgAAAAAAAE Chris Yep kindly cross-verified my suspicion as a bug. An excerpt of Chris' verification is below. The full thread on Facebook can be found here: https://www.facebook.com/groups/backgammonstrategy/permalink/3817038441898133/ Not critical, but please can the bug be fixed? Thank you. -------- >> CY *Yes, this error (bug) has likely existed for many years.I just checked all the boundary cases now. XG's doubling advice matches that given in Tom Keith's paper if the difference ("leader's" Keith Count minus "trailer's" Keith Count) is 2, 3, or 4. GNU's doubling advice matches that given in the paper if the difference is 3 or 4; however, if the difference is 2, GNU gives incorrect doubling advice (as you observed in your bearoff position).In addition to this error, however, GNU also doesn't truncate the "1/7" adjustment. According to the paper, the player on roll is supposed to increase his count by one seventh of the previous count, rounding down. GNU doesn't do any rounding. For example, if GNU's count is 36, it will increase this count by 36/7 (5.14) for a final count of 41.14. XG, on the other hand, will round the final count down to 41, as specified by the paper. Because GNU doesn't truncate this adjustment, additional errors occur (example below).In the position below, XG evaluates the Keith Counts as 41 to 37, so it recommends double/take. GNU, on the other hand, evaluates the Keith Counts as 41.14 to 37 (a difference of 4.14, which is more than 4), so it recommends a no double. In this position, XG is correct and GNU is incorrect (according to the paper).* [image: May be an image of text that says "19 20 21 22 23 24 13 1314 14 15 16 131415161718 1718 17 18 WNW 64 KG MAI Ganmon eXtreme ko extreme Ganmon 121110 121110987 8 12 11 10 9 654321 3 6 5 4"] <https://www.facebook.com/photo.php?fbid=10231708555754825&set=p.10231708555754825&type=3&__cft__[0]=AZWP4gT20yOUew61xt8Vj7zf0P-Cbjd9CCfNbyy7VFEWOE-6qQ5wPtr21YFqKUtQUOYGhET785qp1dmj4MxJLXbT1wyhqYHAehqHe9QgUvqBVlZ0PhQkgzhGksZNq6DPuE7PUBvP8SFxholSKkJ5-uTW8buKTe7C7mTzbG7I5Pa2a1WOf0hpX9jUZ3X8TnYSWm5E6VxM6y8a_vXXwoNNBJc-&__tn__=R]-R>
