numberformat question

[John Balgenorth]

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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