[Numpy-discussion] numpy log and exceptions

Nathaniel Smith njs at pobox.com
Wed Oct 22 09:43:05 EDT 2014


I guess we could make this more consistent by hand if we wanted - isnan is
pretty cheap?
On 22 Oct 2014 07:44, "Julian Taylor" <jtaylor.debian at googlemail.com> wrote:

> On 22.10.2014 05:52, Daniel Hyams wrote:
> >
> > I would have thought that this snippet would raise an exception:
> >
> > import numpy
> > numpy.seterr(all='raise')
> > a = numpy.array([1.0,0.0,-1.0])
> > b = numpy.log(a)
> >
> > I get as a result (in b): [0, -Inf, NaN]
> >
> > It's basically the same issue as:
> >
> > http://numpy-discussion.10968.n7.nabble.com/numpy-log-does-not-raise-
> > exceptions-td5854.html
> >
> > Except that I have explicitly set the error flags to raise exceptions.
> It
> > works fine for sqrt(), but not for log().  I've checked numpy 1.4.0 and
> > 1.7.1 and both have the same behavior.
> >
> > Is there a way to force the log (and log10) function to raise an
> exception
> > on invalid input?
> >
>
> What platform are you using?
> whether you get exceptions or not depends on your math library.
>
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