XorshiftEngine

Xorshift generator. Implemented according to Xorshift RNGs (Marsaglia, 2003) when the size is small. For larger sizes the generator uses Sebastino Vigna's optimization of using an index to avoid needing to rotate the internal array.

Period is 2 ^^ nbits - 1 except for a legacy 192-bit uint version (see note below).

struct XorshiftEngine(UIntType, uint nbits, int sa, int sb, int sc)
struct XorshiftEngine (
UIntType
uint nbits
int sa
int sb
int sc
) if (
isUnsigned!UIntType &&
!(
sa > 0 &&
sb > 0
&&
sc > 0
)
) {
enum bool isUniformRandom;
enum empty;
enum UIntType min;
enum UIntType max;
this(UIntType x0);
void seed(UIntType x0);
UIntType front [@property getter];
void popFront();
typeof(this) save [@property getter];
}
template XorshiftEngine(UIntType, int bits, int a, int b, int c)

Constructors

this this(UIntType x0): Constructs a XorshiftEngine generator seeded with x0.

Members

Functions

popFront void popFront(): Advances the random sequence.
seed void seed(UIntType x0): (Re)seeds the generator.

Manifest constants

empty enum empty;: Always false (random generators are infinite ranges).

Properties

front UIntType front [@property getter]: Returns the current number in the random sequence.
save typeof(this) save [@property getter]: Captures a range state.

Variables

isUniformRandom enum bool isUniformRandom;: Mark this as a Rng
max enum UIntType max;: Largest generated value.
min enum UIntType min;: Smallest generated value.

Examples

alias Xorshift96  = XorshiftEngine!(uint, 96,  10, 5,  26);
auto rnd = Xorshift96(42);
auto num = rnd.front;  // same for each run
assert(num == 2704588748);