[Numpy-discussion] [Numpy] quadruple precision
Wed Feb 29 13:52:07 CST 2012
Le 29/02/2012 16:22, Paweł Biernat a écrit :
> Is there any way to interact with Fortran's real(16) (supported by gcc
> and Intel's ifort) data type from numpy? By real(16) I mean the
> binary128 type as in IEEE 754. (In C this data type is experimentally
> supported as __float128 (gcc) and _Quad (Intel's icc).)
I googled a bit this "__float128". It seems a fairly new addition (GCC
4.6, released March 2011).
The related point in the changelog  is :
"GCC now ships with the LGPL-licensed libquadmath library, which
provides quad-precision mathematical functions for targets with a
__float128 datatype. __float128 is available for targets on 32-bit x86,
x86-64 and Itanium architectures. The libquadmath library is
automatically built on such targets when building the Fortran compiler."
It seems this __float128 is newcomer in the "picture of data types" that
Matthew just mentioned.
As David says, arithmetic with such a 128 bits data type is probably not
"hardwired" in most processors (I mean Intel & friends) which are
limited to 80 bits ("long doubles") so it may be a bit slow. However,
this GCC implementation with libquadmath seems to create some level of
abstraction. Maybe this is one acceptably good way for a real "IEEE
float 128" dtype in numpy ?
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 900 bytes
Desc: OpenPGP digital signature
Url : http://mail.scipy.org/pipermail/numpy-discussion/attachments/20120229/0508e7f0/attachment.bin
More information about the NumPy-Discussion