[Numpy-discussion] reseed random generator (1.19)

[Robert Kern]

On Mon, Jun 29, 2020 at 8:02 AM Neal Becker <ndbecker2 at gmail.com> wrote:

> I was using this to reset the generator, in order to repeat the same
> sequence again for testing purposes.
>

In general, you should just pass in a new Generator that was created with
the same seed.

def function_to_test(rg):
    x = rg.standard_normal()
    ...

SEED = 12345...

rg = np.random.default_rng(SEED)
function_to_test(rg)
rg = npp.random.default_rng(SEED)
function_to_test(rg)

Resetting the state of the underlying BitGenerator in-place is possible, as
Kevin showed, but if you can refactor your code so that there isn't a
persistent Generator object between these runs, that's probably better.
It's a code smell if you can't just pass in a fresh Generator; in general,
it means that your code is harder to use, not just because we don't expose
an in-place seed() method.

-- 
Robert Kern
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