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hrbigelow@gmail.com 05-15-2006 04:59 AM

any floating point library with more exponent bits?
 
hi,
i was wondering if anyone has ever seen a floating point library that
uses at least 20 bits to represent the exponent, rather than the 11
bits for a double-precision standard IEEE-754 float. thanks in
advance!

henry


Gordon Burditt 05-15-2006 05:13 AM

Re: any floating point library with more exponent bits?
 
> i was wondering if anyone has ever seen a floating point library that
>uses at least 20 bits to represent the exponent, rather than the 11
>bits for a double-precision standard IEEE-754 float. thanks in
>advance!


IEEE extended-precision seems to use 15 bits for the exponent
(including exponent sign). That gets up to 1.1e+4932 or so.
I don't know of any hardware that uses more (not to say there
isn't any). Software emulation is possible (but likely slow).

Gordon L. Burditt

hrbigelow@gmail.com 05-15-2006 05:43 AM

Re: any floating point library with more exponent bits?
 
thanks! do you know of any software emulation package that is good,
but short of "arbitrary precision" library? i guess what i'm after is
"extended range", rather than "extended precision". and, if there is a
free library, i'd rather use that than re-tool my algorithm (a bayesian
network, which alternately sums, multiplies and divides numbers, and
would be very hard to re-write in log-space).

thanks again,

henry


azi.stdout@gmail.com 05-15-2006 07:19 AM

Re: any floating point library with more exponent bits?
 
Gnu MP Bignum Library perhaps : http://www.swox.com/gmp/


jacob navia 05-15-2006 07:37 AM

Re: any floating point library with more exponent bits?
 
hrbigelow@gmail.com a écrit :
> hi,
> i was wondering if anyone has ever seen a floating point library that
> uses at least 20 bits to represent the exponent, rather than the 11
> bits for a double-precision standard IEEE-754 float. thanks in
> advance!
>
> henry
>

lcc-win32 offers a 350 bits library

htpp://www.cs.virginia.edu/~lcc-win32

hrbigelow@gmail.com 05-17-2006 04:08 PM

Re: any floating point library with more exponent bits?
 
thanks gordon. i'm actually writing in o'caml :) so unfortunately the
long double is not available. so far i'm using gmp as a software
emulation. any idea how much faster hardware is from software?

thanks again,

henry


hrbigelow@gmail.com 05-17-2006 04:09 PM

Re: any floating point library with more exponent bits?
 
thanks for the excellent tip. i'm now using gmp and so far works great.



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