absolutely, though even an epsilon is a bit of a hack IMHO. given the more ops you do the greater the potential discrepancy, and, i guess, you get a normal dist. of values, so any epsilon only has a probability of working, albeit potentially astronomically high probability.
so then why even have float equality in the/any language at all? or might be nice if vet warned On Sunday, 26 January 2020 03:34:11 UTC, Kurtis Rader wrote: > > This is why you should never, ever, do a simple equality test involving a > F.P. value derived from a calculation. You always have to apply an > epsilon to define a range within which the two F.P. values should be > considered equal. > On Sat, Jan 25, 2020 at 7:14 PM Jason E. Aten <j.e...@gmail.com > <javascript:>> wrote: > >> >> https://play.golang.org/p/87bDubJxjHO >> >> I'd like to truncate a float64 to just 2 decimal places (in base 10), but >> math.Trunc is not helping me here... ideally I put 0.29 in and I get 0.29 >> out. >> Suggestions? Playground examples appreciated. >> >> package main >> >> import ( >> "fmt" >> "math" >> ) >> >> // truncate off everything after the last two decimals, no rounding. >> func decimal2(x float64) float64 { >> return math.Trunc(x*100) / 100 >> } >> >> func main() { >> x := 0.29 >> y := decimal2(x) >> fmt.Printf("x=%v -> y = %v", x, y) // prints x=0.29 -> y=0.28 >> } >> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golan...@googlegroups.com <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/96528d64-a670-45ba-ad4c-0701dcd0d78d%40googlegroups.com >> >> <https://groups.google.com/d/msgid/golang-nuts/96528d64-a670-45ba-ad4c-0701dcd0d78d%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > > > -- > Kurtis Rader > Caretaker of the exceptional canines Junior and Hank > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/229c73ce-88fb-46a0-a2ee-8454cbaa6ae5%40googlegroups.com.
