On Mon, Mar 11, 2013 at 9:46 AM, Robert Kern <robert.kern@gmail.com> wrote:
On Sun, Mar 10, 2013 at 6:12 PM, Siu Kwan Lam <siu@continuum.io> wrote:
My suggestion to overcome (1) and (2) is to allow the user to select between the two implementations (and possibly different algorithms in the future). If user does not provide a choice, we use the MT19937-32 by default.
numpy.random.set_state("MT19937_64", …) # choose the 64-bit implementation
Most likely, the different PRNGs should be different subclasses of RandomState. The module-level convenience API should probably be left alone. If you need to control the PRNG that you are using, you really need to be passing around a RandomState instance and not relying on reseeding the shared global instance.
+1
Aside: I really wish we hadn't exposed `set_state()` in the module API. It's an attractive nuisance.
And our own test suite is a serious offender in this regard, we have tests that fail if you run the test suite in a non-default order... https://github.com/numpy/numpy/issues/347 I wonder if we dare deprecate it? The whole idea of a global random state is just a bad one, like every other sort of global shared state. But it's one that's deeply baked into a lot of scientific programmers expectations about how APIs work... -n