On 2011-06-01, Chris Angelico <ros...@gmail.com> wrote: > On Wed, Jun 1, 2011 at 12:59 PM, Carl Banks <pavlovevide...@gmail.com> wrote: >> On Sunday, May 29, 2011 7:53:59 PM UTC-7, Chris Angelico wrote: >>> Okay, here's a question. The Python 'float' value - is it meant to be >>> "a Python representation of an IEEE double-precision floating point >>> value", or "a Python representation of a real number"? >> >> The former. ?Unlike the case with integers, there is no way that I know of >> to represent an abstract real number on a digital computer. > > This seems peculiar. Normally Python seeks to define its data types > in the abstract and then leave the concrete up to the various > implementations - note,
But, "real numbers" and "IEEE float" are so different that I don't think that it would be a wise decision for people to pretend they're working with real numbers when in fact they are working with IEEE floats. > for instance, how Python 3 has dispensed with 'int' vs 'long' and > just made a single 'int' type that can hold any integer. Those concepts are much closer than "real numbers" and "IEEE floats". > Does this mean that an implementation of Python on hardware that has > some other type of floating point must simulate IEEE double-precision > in all its nuances? I certainly hope so. I depend on things like propogation of non-signalling nans, the behavior of infinities, etc. > I'm glad I don't often need floating point numbers. They can be so > annoying! They can be -- especially if one pretends one is working with real numbers instead of fixed-length binary floating point numbers. Like any tool, floating point has to be used properly. Screwdrivers make very annoying hammers. -- Grant Edwards grant.b.edwards Yow! How's it going in at those MODULAR LOVE UNITS?? gmail.com -- http://mail.python.org/mailman/listinfo/python-list