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    <p>I'd use one instance to seed the others. I'm pretty sure you can do this safely fairly easily.</p> <ul> <li>Even small changes in the state space cause fairly large changes downstream - if you can ensure they don't have exactly the same starting space (and no identical state prefix), I wouldn't worry about producing identical numbers. For instance, using just the values 1,2,3 to seed three threads would work fine - you don't even need to seed the entire space. Another advantage: by using clearly predictable seeds you can easily discredit the idea that you're cherry-picking any runs (assuming you're trying to demonstrate something).</li> <li>It's trivial to seed in a way that means the resultant "children" are highly un-correlated. Just iterate in a breadth-first fashion; i.e. if you want to seed N x 623 int values, don't seed 623 values sequentially, but pick the first N and distribute, then the next N etc. Even if there's some correlation between the seeder and the children, the correlation between the various children should be virtually non-existant - and that's all you care about.</li> <li>I'd prefer an algorithm that allows deterministic execution whenever possible, so <em>depending</em> on urandom is not attractive. This makes debugging easier.</li> <li>Finally, and obviously - test. These PRNG are fairly robust, but by all means eyeball the results and do a few correlation tests inspired by what you're simulating. Most problems should be obvious - either you've seeded badly and there are obvious repeating subsequences, you you've seeded well, and then the quality is dictated by the PRNG limitations.</li> <li>For final executions, after you're done testing, you can seed the first of 623 state values using urandom for peace of mind and/or the thread ID.</li> </ul>
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    1. COSeeding in parallel sounds very interesting in terms of behaviour. Implementing it might be a hassle, since I can't simply pass one PRNG as seed to all the others. But I guess I could simply generate the 8*623 bytes up front, transpose that matrix and pass the resulting arrays to the constructors or seed functions. Or just seed with one integer as you suggested. The point about debugging is very valid, too.
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    2. COYeah, transposing would do the trick. Or just use 2 nested loops - you don't actually need to do this in parallel, because once you're done you can always hand off the PRNG afterwards.
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    3. COI'm not thinking about doing the initialization in parallel. But the seeding step using boost appears to be an atomic operation; I can't seed the individual values directly. So I'll have to find a way to provide a whole state vector for a single invocation.
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