[Numpy-discussion] 0/0 is 0 or nan?
Robert Kern
robert.kern@gmail....
Tue Mar 13 23:30:17 CDT 2007
Christopher Ball wrote:
> In Python, a/0 gives a divide-by-zero error for any a, but in numpy, I
> can ignore divide-by-zero errors. If I do this, why can't I still have
> 0/0 be nan?
>
> seterr(divide='ignore')
> a=array([0],dtype=float_)
> b=array([0],dtype=float_)
> divide(a,b)
>
> gives nan, so why doesn't
>
> seterr(divide='ignore')
> a=array([0],dtype=int_)
> b=array([0],dtype=int_)
> divide(a,b)
>
> also give nan, rather than 0 as it gives now? Is this because inf is not
> something to which an int can be set (as Christopher Barker wrote), and
> it matches Python's behavior?
Pretty much. ints operated with ints will give ints, not floats. nan and inf are
floating point concepts.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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