Question

I need to generate a controlled sequence of pseudo-random numbers, given an initial parameter. For that I’m using the standard python random generator, seeded by this parameter. I’d like to make sure that I will generate the same sequence across systems (Operating system, but also Python version).

In summary: Does python ensure the reproducibility / portability of it’s pseudo-random number generator across implementation and versions?

Answer 1

No, it doesn’t. There’s no such promise in the random module’s documentation.

What the docs do contain is this remark:

Changed in version 2.3: MersenneTwister replaced Wichmann-Hill as the default generator

So a different RNG was used prior to Python 2.3.

So far, I’ve been using numpy.random.RandomState for reproducible pseudo-randomness, though it too does not make the formal promise you’re after.

If you want full reproducibility, you might want to include a copy of random‘s source in your program, or hack together a "P²RNG" (pseudo-pseudo-RNG) from hashlib.