[Numpy-discussion] Infinity definitions
Thu Apr 10 13:57:57 CDT 2008
On 10/04/2008, Travis E. Oliphant <firstname.lastname@example.org> wrote:
> Bruce Southey wrote:
> > Hi,
> > Since we are discussing namespace and standardization, I am curious in
> > why there are multiple definitions for defining infinity in numpy when
> > perhaps there should be two (one for positive infinity and one for
> > negative infinity). I really do understand that other people have use of
> > these definitions and that it is easier to leave them in than take them
> > out. Also, it is minor reduction in namespace because I do know that
> > much of the namespace is either defining variables (like different
> > floats and complex numbers) or mathematical functions (like logs and
> > trig functions).
> > Currently we have:
> > numpy.Inf
> > numpy.Infinity
> > numpy.inf
> > numpy.infty
> > numpy.NINF
> > numpy.PINF
> > Most of these are defined in numeric.py: 'Inf = inf = infty = Infinity =
> > PINF'
> > In the f2py/tests subdirectories, the files return_real.py and
> > return_complex.py uses both 'inf','Infinity'.
> > The only occurrence of NINF and PINF are in core/src/umathmodule.c but I
> > don't see any other usage.
> > There does not seem to be any use of 'infty'.
> I think this is a product of bringing together a few definitions into
> one and not forcing a standard.
> should be used except for backward compatibility.
The others have some use if you want to be able to use the results of
repr() as literals - as I understand it the output representation of a
NaN depends on the C library, and users seeing, say, "NaN" might well
expect to be able to type NaN (after from numpy import NaN) and get a
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