[Numpy-discussion] Backwards-incompatible improvements to numpy.random.RandomState

Antony Lee antony.lee at berkeley.edu
Sun May 24 17:09:43 EDT 2015


2015-05-24 13:30 GMT-07:00 Sturla Molden <sturla.molden at gmail.com>:

> On 24/05/15 10:22, Antony Lee wrote:
>
> > Comments, and help for writing tests (in particular to make sure
> > backwards compatibility is maintained) are welcome.
>
> I have one comment, and that is what makes random numbers so special?
> This applies to the rest of NumPy too, fixing a bug can sometimes change
> the output of a function.
>
> Personally I think we should only make guarantees about the data types,
> array shapes, and things like that, but not about the values. Those who
> need a particular version of NumPy for exact reproducibility should
> install the version of Python and NumPy they need. That is why virtual
> environments exist.


I personally agree with this point of view (see original discussion in
#5299, for example); if it was only up to me at least I'd make
RandomState(seed) default to the latest version rather than the original
one (whether to keep the old versions around is another question).  On the
other hand, I see that this long-standing debate has prevented obvious
improvements from being added sometimes for years (e.g. a patch for
Ziggurat normal variates has been lying around since 2010), or led to
potential API duplication in order to fix some clearly undesirable behavior
(dirichlet returning "nan" being described as "in a strict sense not really
a bug"(!)), so I'm willing to compromise to get this moving forward.

Antony
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/numpy-discussion/attachments/20150524/dab1243e/attachment.html>


More information about the NumPy-Discussion mailing list