I´ve found ´format´ and ´round´ functions quite helpful, see https://the-m6.net/blog/fixed-point-arithmetic-in-picolisp.html
On 12 Jul 2017 18:52, "Jimmie Houchin" <jlhouc...@gmail.com> wrote: > Hello, > > I am trying to understand something about PicoLisp and Fixpoint numbers. > > I am writing an app and would consider PicoLisp should I get my head > around Lisp. But I do not understand how to use numbers. > > I use a lot of floating point numbers and lots of calculations. From > simple experiments it seems that the numbers and math appear to be accurate > and correct. However I have no understanding of how to present a final > result formatted correctly. > > Example: > > (setq *Scl 5) ;; or could be 10 ... > > (* 0.00009 0.0009) > > -> 81 > > From another language: 0.0000000081 > > or: > > (setq *Scl 20) > > (* 9.9 9.789 9.56789) > > -> 927234744579000000000000000000000000000000000000000000000000000 > > From another language 20 decimal points printed after converting to > floating point: > > 927.23474457900010747835 > > The math looks fine as far as these simple examples go. But if I do > several to dozens of different calculations with floating point numbers > with unknown values until streamed to the app from some source. How do I > know where the decimal point really belongs in order to format correctly > for human use? Is it possible? > > I personally do not have a problem with fixpoint for internal use, as that > is simply an implementation issue. However I do need to convert back to the > best floating point representation for display or storage. > > Any help in understanding would be greatly appreciated. > > Thanks. > > Jimmie > > -- > UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe >
