[SciPy-dev] random seed in scipy.stats
Sun Apr 20 19:30:43 CDT 2008
On Sun, Apr 20, 2008 at 3:23 PM, Hoyt Koepke <email@example.com> wrote:
> Okay, I'm planning to add this to the stats module this afternoon, and
> I need to check with people on the best way to include the new random
> number features.
> Option 1:
> Allow two additional keyword arguments to the constructor and to the
> rvs functions, namely randseed and prng. If neither are given, it
> would default to the current behavior and draw straight from
> numpy.random. If randseed is given, but not prng, it would create a
> random state object with that seed. prng would be a RandomState
> object from numpy.random; if given randseed is ignored and that is
> used to draw the random numbers. Any concerns?
> Option 2:
> have a single additional kw arg like rnginfo or randominfo. If it's a
> RandomState instance, it is used to draw numbers from. If it's
> anything else, it's used to seed the random number generator. If it's
> None, it's discarded.
I prefer just being able to pass in a RandomState object. It's a
subtle encouragement to do the right thing, which is to share a single
RandomState object. People who *really* want to just pass in a seed
just need to wrap that seed with RandomState(seed). "There should be
one-- and preferably only one --obvious way to do it."
> With both options, arguments to the rvs method would override the
> arguments to the constructor, but only for that function call.
> I would personally go for 1., as it seems the potential for API
> confusion is a lot less. Also, 2 wouldn't allow people to pass in
> arbitrary random number generating objects that defined the correct
> methods, whereas 1 would (though this would probably be pretty rare).
> Now if we do 1, is prng the best argument name for the randomstate
> object? I could also use rso, rng, randomstateobject, etc.
<shrug> I like it. I think it's the best mix of terseness and comprehensibility.
"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
-- Umberto Eco
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