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I want to supply a number, and then receive a set of random numbers. However, I want those numbers to be the same regardless of which computer I run it on (assuming I supply the same seed).
Basically my question is: in C++, if I make use of rand(), but supply srand() with a user-defined seed rather than the current time, will I be able to generate the same random number stream on any computer?
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The DRBG produces a sequence of bits from a secret initial value called a seed. A cryptographic DRBG has the additional property that the output is unpredictable given that the seed is not known. A DRBG is sometimes also called a pseudo-random number generator (PRNG) or a deterministic random number generator.
std::mt19937(since C++11) class is a very efficient pseudo-random number generator and is defined in a random header file. It produces 32-bit pseudo-random numbers using the well-known and popular algorithm named Mersenne twister algorithm. std::mt19937 class is basically a type of std::mersenne_twister_engine class.
The seed is the point of this extremely long sequence where the generator starts. So yes, it is deterministic. A pseudo-random number generator is an endlessly repeating fixed list of numbers.
All of this is deterministic. If you start off an instance of Random with the same initial state (which can be provided via a seed) and make the same sequence of method calls on it, you'll get the same results.
There are dozens of PRNGs available as libraries. Pick one. I tend to use Mersenne Twister.
By using an externally supplied library, you bypass the risk of a weird or buggy implementation of your language's library rand(). As long as your platforms all conform to the same mathematical semantics, you'll get consistent results.
MT is a favorite of mine because I'm a physicist, and I use these things for Monte Carlo, where the guarantee of equal-distribution to high dimensions is important. But don't use MT as a cryptographic PRNG!
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