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

[Sturla Molden]

On 24/05/15 17:13, Anne Archibald wrote:
> Do we want a deprecation-like approach, so that eventually people who
> want replicability will specify versions, and everyone else gets bug
> fixes and improvements? This would presumably take several major
> versions, but it might avoid people getting unintentionally trapped on
> this version.
>
> Incidentally, bug fixes are complicated: if a bug fix uses more or fewer
> raw random numbers, it breaks repeatability not just for the call that
> got fixed but for all successive random number generations.


If a function has a bug, changing it will change the output of the 
function. This is not special for random numbers. If not retaining the 
old erroneous output means we break-backwards compatibility, then no 
bugs can ever be fixed, anywhere in NumPy. I think we need to clarify 
what we mean by backwards compatibility for random numbers. What 
guarantees should we make from one version to another?


Sturla