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Re: Comments for P0205 and P2060: Mersenne twister can actually generate 7 and 13

From: Dimitrij Mijoski <dmjpp_at_[hidden]>
Date: Fri, 19 Nov 2021 17:55:05 +0100
On Fri, 2021-11-19 at 10:15 -0500, Jason McKesson via Std-Proposals
> On Fri, Nov 19, 2021 at 9:51 AM Dimitrij Mijoski via Std-Proposals
> <std-proposals_at_[hidden]> wrote:
> >
> > This is just one more argument that that "test", i.e. distribution of
> > the first outputs after seeding, is not a good test for the quality
> > of any PRNG. The P in PRNG has meaning, of course they are not
> > perfect, they are pseudo-random. They are designed to give uniformity
> > after multiple calls after seeding. See my previous comment here
> > https://lists.isocpp.org/std-proposals/2021/11/3354.php
> The idea that you shouldn't expect reasonable randomness from an RNG
> until you prime the pump by extracting some number of random bits from
> it is ridiculous. That's the *entire point* of seeding the RNG: to
> prime the pump so that you can get good randomness from the first bit
> you extract.

But there is good randomness, who said it isn't good? Do you trust a
random article on the internet with a lot of unproven claims and
without a method to replicate their false results? I already proved
that it contains wrong information. Please give a proof with code that
measures the distribution of the first outputs after seeding of various
different PRNGs, and then make your claims.

> His point is pretty straightforward. If an RNG has a gigantic seed,
> then that's a problem with the RNG, not with the person wanting to
> fill up *whatever* seed an RNG has. Logically, it makes no sense not
> to fill up the entire RNG seed.
> And note, we're not taking away the ability to pick however much
> randomness you want. We're making it easier to fill up the entirety of
> the seed with randomness. You're effectively saying that people
> shouldn't want that, but the only reason not to do it is because some
> RNGs have gigantic seeds. He's saying that this is a problem with the
> RNG, not with the concept of filling up the seed entirely.

You are not making a difference between seed and state. If the PRNG
state is huge, the seed does not need to be huge. And yes I'm saying
that people should not want the seed to be always the same size as the
internal state.

Received on 2021-11-19 10:56:30