[Numpy-discussion] float96 on windows32 is float64?

Matthew Brett matthew.brett@gmail....
Fri Mar 16 20:39:18 CDT 2012


Hi,

On Fri, Mar 16, 2012 at 5:36 AM,  <josef.pktd@gmail.com> wrote:
> On Fri, Mar 16, 2012 at 2:10 AM, Ilan Schnell <ischnell@enthought.com> wrote:
>> I just did a quick test across all supported EPD platforms:
>> win-64: float96 No, float128 No
>> win-32: float96 No, float128 No
>> osx-64: float96 No, float128 Yes
>> osx-32: float96 No, float128 Yes
>> rh3-64: float96 No, float128 Yes
>> rh3-32: float96 Yes, float128 No
>> rh5-64: float96 No, float128 Yes
>> rh5-32: float96 Yes, float128 No
>> sol-64: float96 No, float128 Yes
>> sol-32: float96 Yes, float128 No
>
>
> numpy 1.5.1 MingW, on python 2.6 win32 has float96, float128 no
> numpy 1.6.1 Gohlke (MKL I think) on python 3.2 win64   no float96, no float128
>
> Josef
>
>>
>> I have no explanation for this, but I'm guessing David C. has.
>> I'll look more into this tomorrow.
>>
>> - Ilan

Oh dear - I completely forgot the previous thread that I started on
this : http://mail.scipy.org/pipermail/numpy-discussion/2011-November/059233.html

You young people, don't laugh, this will happen to you one day.

Anyway, summarizing, it appears that windows float96:

a) Is stored as an 80 bit extended precision number
b) Uses float64 precision for all calculations.
c) Is specific to MingW builds of numpy - I think.

Perhaps David C you'll correct me if I've got that wrong,

Best,

Matthew


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