https://bugs.documentfoundation.org/show_bug.cgi?id=137679
--- Comment #72 from b. <[email protected]> --- just one point which wasn't clear enough to me in the past: the difference of a FP calculation vs. the user intended decimal calculation adds up from: a.) the imprecision in the bin representation of the operands, b.) in operation rounding, e.g. '= 0.2 + 0.1' with doubles: 0.2 bin representation is about 1.11E-17 overshot, 0.1 bin representation is about 5.55E-18 overshot, and as the sum doesn't meet a double value it's rounded, in this case rounded up, by additional 2.77E-17. this way we get the irritating 0.30000000000000004 as result. with 'Kahaning' or Neumaier we have access to the 2.77E-17 rounding difference, not! to the representation deviations. thus 'by chance' a set with randomly distributed up and down deviations will produce improved results with Kahan or Neumaier, while sets with 'systematic drift' - e.g. all positive - will gain less benefit. -- You are receiving this mail because: You are the assignee for the bug.
