[Numpy-discussion] arange and floating point arguments

Eike Welk eike.welk@gmx....
Fri Sep 14 14:49:49 CDT 2007


On Friday 14 September 2007 20:12, Charles R Harris wrote:

> Since none of the numbers are  exactly represented in IEEE floating
> point, this sort of oddity is expected.  If you look at the exact
> values, (.4 + .2)/.1 > 6 and .6/.1 < 6 . That said, I would expect

You hit send too fast! The fractions that can be represented exactly 
in binary are: 1/2, 1/4, 1/8, ... and not 2/10, 4/10, 8/10 .... 

See here:

In [1]:0.5 == .25+.25
Out[1]:True

In [2]:.5
Out[2]:0.5

In [3]:.25
Out[3]:0.25

In [4]:.125
Out[4]:0.125

In [8]:.375 == .25 + .125
Out[8]:True


Regards,
Eike.


More information about the Numpy-discussion mailing list