[erlang-questions] changes in native functions for the next otp release.
Angel
clist@REDACTED
Sat Jan 23 11:01:30 CET 2010
On Viernes, 22 de Enero de 2010 02:09:52 Richard O'Keefe escribió:
> On Jan 22, 2010, at 1:40 AM, Angel wrote:
> > Hi
> >
> > Some months ago, i discovered that square root of bignums is not
> > implemented
> > in erlang.
>
> ?
>
> 1> math:sqrt(1 bsl 801).
> 3.65185e+120
>
> math:sqrt is just as much implemented for bignums as it is for fixnums.
>
> Or do you mean "the greatest integer X such that X**2 <= Y",
> the "integer square root"? I didn't think Erlang had that for fixnums
> either.
>
i mean sqrt for bignums was broken.
25-08-2009 "bignum sqrt broken in erlang?"
See my message on that ocasión:
---
Hi
Iet ab=N
let M=(a+1)(b+1);
M=ab+a+b+1 that is N +a +b +1 so M > N
Ok but in erlang...
Erlang R13B01 (erts-5.7.2) [source] [rq:1] [async-threads:0] [hipe] [kernel-
poll:false]
Eshell V5.7.2 (abort with ^G)
1> N=71641520761751435455133616475667090434063332228247871795429.
71641520761751435455133616475667090434063332228247871795429
2> R0=trunc(math:sqrt(N)).
267659337146589062070609641472
3> R1=R0+1.
267659337146589062070609641473
4> M=R1*R1.
71641520761751431352030800763682813030352458120945601609729
5> M -N > 0.
false
where is the problem? That's erlang or the gmp library?
/Angel"
this was on R13B1 i think (have to re-test on current versión) is still
broken.
Im probing some supeesecrete variations of "fermat little's theorem" on RSA
numbers clearly is a problem if native math:sqrt still broken and port
latencies (serialitation and parsing) of my actual code begin to annoy me.
So it is worth a NIF?
Thanks in advance, Angel
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