Re: Any good package for mathematical function in Ada?

["Nasser M. Abbasi" <nma@12000.org>]

On 6/1/2020 6:34 AM, Dmitry A. Kazakov wrote:
89122152724401671806000989156340
>>
>> Want 1,000 digits? 2,000 digits? all can be done.
> 
> In how many microseconds?
> 

In my PC, intel i-7-8086K CPU, 4 GHZ, it takes 6.2*10^-7 second
for 20,000 digits (I put ";" to prevent the 20,000 digits from
being printed on screen)

In[20]:= RepeatedTiming[N[BesselJ[0,1],20000];]
Out[20]= {6.2*10^-7,Null}

"RepeatedTiming[expr] evaluates expr repeatedly and returns a list of
the average time in seconds used, together with the result obtained.
"

>> I think these systems both link to GMP "GNU Multiple Precision
>> Arithmetic Library"
>> for this. "There are no practical limits to the precision "
>> https://en.wikipedia.org/wiki/GNU_Multiple_Precision_Arithmetic_Library
> 
> There is no best numerical library as requirements greatly vary. One
> would probably never want to use multiple precision arithmetic in
> production code. Less improbable, but still, in laboratory computations
> when other factors control precision.
> 
> As for GMP specifically, I think that arbitrary precision numeric types
> must be an integral part of Ada. Unfortunately, this would introduce
> same mess Unbounded_String did. So, for now, I would not push for them
> until the language type system mature to accommodate them smoothly.
> 

Best,
--Nasser