Is there a way to obtain the state of the random n

问题:

This question already has an answer here:

• Retrieve RNG seed in julia 5 answers

Say I seed 123 with srand(123), and run rand() X times. Later, I want to be able to restart Julia and seed a number (or state) such that when I run rand() again I get the number that would have been generated if I had seed 123 and run rand() X + 1 times. Is there any way I can do that, or do I really have to run rand() X times to obtain the state I want?

回答1:

If the solution with custom random number generator presented in Retrieve RNG seed in julia is not feasible for you the best I can come up with is to copy the whole structure of global random number generator:

function reset_global_rng(rng_state)
    Base.Random.GLOBAL_RNG.seed = rng_state.seed
    Base.Random.GLOBAL_RNG.state = rng_state.state
    Base.Random.GLOBAL_RNG.vals = rng_state.vals
    Base.Random.GLOBAL_RNG.idx = rng_state.idx
end

rs = deepcopy(Base.Random.GLOBAL_RNG)
println(rand(5))
# [0.301558,0.602108,0.220952,0.0338732,0.553414]
reset_global_rng(rs)
println(rand(5))
# [0.301558,0.602108,0.220952,0.0338732,0.553414]

although I am not 100% sure how it does not come into interaction with dsfmt_gv_srand() in random.jl.