finding out the precision of floats

Robert Kern robert.kern at gmail.com
Sun Feb 25 20:33:55 EST 2007


Dennis Lee Bieber wrote:
> On 25 Feb 2007 05:31:11 -0800, "John Machin" <sjmachin at lexicon.net>
> declaimed the following in comp.lang.python:
> 
>> Evidently not; here's some documentation we both need(ed) to read:
>>
>> http://docs.python.org/tut/node16.html
>> """
>> Almost all machines today (November 2000) use IEEE-754 floating point
>> arithmetic, and almost all platforms map Python floats to IEEE-754
>> "double precision".
>> """
>> I'm very curious to know what the exceptions were in November 2000 and
>> if they still exist. There is also the question of how much it matters
> 
> 	Maybe a few old Vaxes/Alphas running OpenVMS... Those machines had
> something like four or five different floating point representations (F,
> D, G, and H, that I recall -- single, double, double with extended
> exponent range, and quad)

I actually used Python on an Alpha running OpenVMS a few years ago. IIRC, the
interpreter was built with IEEE floating point types rather than the other types.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco




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