[Python-ideas] Python Numbers as Human Concept Decimal System

[Mark H. Harris]

On Saturday, March 8, 2014 4:01:47 AM UTC-6, Mark Dickinson wrote

On the other hand, we probably shouldn't lend *too* much weight to IEEE 
> 754, especially when talking about choice of precision.  IEEE 754 isn't a 
> perfect fit for Decimal:  the IEEE standard is mostly concerned with fixed 
> width decimal formats, which is subtly different from Mike Cowlishaw's 
> approach of "extensible precision" where the precision is not so closely 
> tied to the format.  Python's decimal module is based on Cowlishaw's 
> standard, not on IEEE 754.
>

hi Mark,   Mike's notes include the following:

 -- the package meets the requirements of IEEE 854-1987 (with minor
     restrictions discussed below), including support for subnormal
     numbers, -0, NaNs, infinities, etc.  It also conforms to the
     floating-point arithmetic definition in ANSI X3.274-1996.

  

     here: http://grouper.ieee.org/groups/754/email/msg00429.html

The extensible precision is what makes the standard interesting.


marcus

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20140308/1b7c99ee/attachment-0001.html>