Python math is off by .000000000000045

Tim Wintle tim.wintle at teamrubber.com
Sat Feb 25 20:08:47 CET 2012


On Sat, 2012-02-25 at 09:56 -0800, Tobiah wrote: 
> > For every floating point
>  > number there is a corresponding real number, but 0% of real numbers
>  > can be represented exactly by floating point numbers.
> 
> It seems to me that there  are a great many real numbers that can be
> represented exactly by floating point numbers.  The number 1 is an
> example.
> 
> I suppose that if you divide that count by the infinite count of all
> real numbers, you could argue that the result is 0%.

It's not just an argument - it's mathematically correct.

The same can be said for ints representing the natural numbers, or
positive integers.

However, ints can represent 100% of integers within a specific range,
where floats can't represent all real numbers for any range (except for
the empty set) - because there's an infinate number of real numbers
within any non-trivial range.


Tim






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