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