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Function `std.random.unpredictableSeed`

A "good" seed for initializing random number engines. Initializing with unpredictableSeed makes engines generate different random number sequences every run.


						
				uint unpredictableSeed() nothrow @property @nogc @trusted;
						
						
				alias unpredictableSeed(UIntType)
				 = unpredictableSeed;

Function unpredictableSeed

Alias unpredictableSeed

Returns

A single unsigned integer seed value, different on each successive call

Note

In general periodically 'reseeding' a PRNG does not improve its quality and in some cases may harm it. For an extreme example the Mersenne Twister has 2 ^^ 19937 - 1 distinct states but after seed(uint) is called it can only be in one of 2 ^^ 32 distinct states regardless of how excellent the source of entropy is.

Example

auto rnd = Random(unpredictableSeed);
auto n = rnd.front;
static assert(is(typeof(n) == uint));

Authors

Andrei Alexandrescu Masahiro Nakagawa (Xorshift random generator) Joseph Rushton Wakeling (Algorithm D for random sampling) Ilya Yaroshenko (Mersenne Twister implementation, adapted from mir-random)

License

Boost License 1.0.