How to resume a PRNG, at a later time deterministically?

[clamydo]

How can I access and save the state in a way, that I can resume the pseudo random number generator at a later time?

[clamydo]

As a workaround I've implemented a method for a PcgEngine<IType,...>

impl<Itype, Xtype, MulMix, OutMix> PcgEngine<Itype, Xtype, SpecificSeqStream<Itype>, MulMix, OutMix>
    where Itype: PcgOps + BitSize + Clone,
          Xtype: PcgOps + BitSize,
          MulMix: Multiplier<Itype>,
          OutMix: OutputMixin<Itype, Xtype>,
          SpecificSeqStream<Itype>: Stream<Itype>,
          PcgEngine<Itype, Xtype, SpecificSeqStream<Itype>, MulMix, OutMix>: Rng
{
    pub fn extract_seed(&self) -> [Itype; 2] {
        [self.state.clone(), self.stream_mix.get_stream()]
    }
}

I'm not sure, if your interested in adding something like this also for the other subtypes? In the long run, it would be probably wise to add something like extract_seed() to the SeedableRng trait in the rand crate.

[clamydo]

Also see rust-random/rand#84.

[robojeb]

@fkjogu sorry for not getting back to you. These past few months have been a whirlwind involving moving and starting a new job.

I like this idea, I toyed with serializing the generators in the "serde" branch.
If you want to submit a pull request for this I would be happy to include it in the library.

If you don't have time, I will get around to implementing it myself sometime soon hopefully.