numberformat question

[Sean Cole (Pi)]

JS should use exactly the same standard as LC
https://www.avioconsulting.com/blog/overcoming-javascript-numeric-precision-issues

2^53, same in JS as LC. IEEE 754

Sean

On Mon, 22 Mar 2021 at 16:14, John Balgenorth via use-livecode <
use-livecode at lists.runrev.com> wrote:

> You might be able to get the info by running your javascript
> from a shell command.  Here is a link that might be of help;
>
>
> https://stackoverflow.com/questions/12659778/is-it-possible-to-run-javascript-files-from-the-command-line
>
> JB
>
>
> > On Mar 22, 2021, at 9:05 AM, jbv via use-livecode <
> use-livecode at lists.runrev.com> wrote:
> >
> > Hi Craig,
> >
> > Thank you for the link, but it doesn't help much :
> >
> > bigDivide(-0.0000007347880794884118999,1000000000)
> > returns 0 , -0.000001
> >
> > what I'm actually trying to do is to transpose in LC
> > an algo for solving cubic equations that runs perfectly
> > in javascript.
> > So my solution will finally be to multiply data by 10^6,
> > run the algo, and then divide the results by 10^6 by
> > treating them as strings and moving the dot...
> > It's not really elegant and especially quite slow, as I
> > need to process large amounts of data and am not sure
> > that I'll be able to use LC for that project (which is
> > so far only a prototype).
> >
> > I don't mean to start another endless thread on this topic,
> > but one thing puzzles me though : I understand that LC doesn't
> > use decimal numbers for internal calculations for reasons
> > of speed, but then how come does js perform high precision
> > calculations without any speed issues ?
> >
> > Best
> >
> > Le 2021-03-22 09:41, Craig Newman via use-livecode a écrit :
> >> Check out this thread in the forum:
> >>
> https://forums.livecode.com/viewtopic.php?f=7&t=25132&p=130985&hilit=longadd#p130985
> >> <
> https://forums.livecode.com/viewtopic.php?f=7&t=25132&p=130985&hilit=longadd#p130985
> >
> >> Craig
> >>>> On Mar 21, 2021, at 7:34 AM, jbv via use-livecode <
> use-livecode at lists.runrev.com> wrote:
> >>> Paul, Sean,
> >>> Thank you both for your answers, although it doesn't really solve my
> problem.
> >>> The most surprising thing is that javascript runs these calculations
> without
> >>> problem :
> >>> (-0.0000007347880794884118999 / 1000000000) returns
> -7.347880794884119e-16
> >>> (-0.0000007347880794884118999 / 1000000000000) returns
> -7.347880794884119e-19
> >>> Best
> >>> Le 2021-03-21 07:11, Sean Cole (Pi) via use-livecode a écrit :
> >>>> Livecode can handle floating point numbers up to 2^52. But then
> >>>> calculations would have to fit within that range in a floating point
> >>>> perspective too. So, once you add that ninth zero to the end of your
> >>>> divider, it struggles with the calculation and returns, effectively,
> number
> >>>> out of range.
> >>>> Fractions in FP binary are tremendously complicated. Calculation in
> it are
> >>>> even more so.
> >>>> https://www.h-schmidt.net/FloatConverter/IEEE754.html
> >>>> On Sat, 20 Mar 2021 at 20:23, Paul Dupuis via use-livecode <
> >>>> use-livecode at lists.runrev.com> wrote:
> >>>>> I don't have an answer, other than to say there has been a LOT of
> >>>>> discussion over the years about the limits of number precision in
> >>>>> LiveCode and a number of enhancement requests and 3rd party libraries
> >>>>> that have attempted to provide a framework for high precision math.
> You
> >>>>> might search the list archives or search the forum on the LC web site
> >>>>> for past discussions about number precision.
> >>>>> On 3/20/2021 3:06 PM, jbv via use-livecode wrote:
> >>>>> > Hi list,
> >>>>> > I am a bit lost :
> >>>>> >
> >>>>> >    set numberformat to ".#########################"
> >>>>> >    put -0.0000007347880794884118999 / 1000
> >>>>> > -- returns -0.0000000007347880794884119  which is ok
> >>>>> >
> >>>>> >    put -0.0000007347880794884118999 / 1000000
> >>>>> > -- returns -0.0000000000007347880794884 -> also ok
> >>>>> >
> >>>>> >    put -0.0000007347880794884118999 / 100000000
> >>>>> > -- returns -0.0000000000000073478807949 -> still ok
> >>>>> >
> >>>>> >    put -0.0000007347880794884118999 / 1000000000
> >>>>> > -- returns 0 -> ?????
> >>>>> >
> >>>>> > Any explanations ?
> >>>>> > Thanks in advance.
> >>>>> > Best,
> >>>>> > jbv
> >>>>> >
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