On Wed, Apr 15, 2015 at 02:04:45AM -0400, George Neuner wrote: > > The measure I was advocating was "difference percentage" based on > the terminology "50% faster". Difference percentage is just the > linear relative change (a ratio) multiplied by 100%. A ratio is a > fraction and the "base" of a fraction is its denominator. [Different > from the "base" of a number. Fraction "base" may be old > terminology, but then I am not very young :-P ] Difference is a > vector quantity, having both magnitude and direction. > > "Faster" vs "slower" is a line and the times for the old and new > versions represent points along that continuum. To compare them you > must decide which difference you want to compute - that is, in which > direction you will be going: new to old, or old to new. > > The [verbose] equation for linear relative change is: ( compared - > compared_to ) / compared_to. > > The difference vector - that is, the direction of the comparison - > determines which of the "old" or "new" points should be substituted > for "compared_to" and so become the base (denominator) of the > resulting fraction.
So undoing a 50% bonus involves a 33.33...% reduction I've often thought that large percentage increases ad decreases should be moderated by natural logarithms to avoid this problem. But then the calculations would become difficult. -- hendrik. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
