SplitMixEngine

Generic SplitMixEngine.

The first parameter mixer should be a explicit instantiation of fmix64 or a predefined parameterization of fmix64 such as murmurHash3Mix or staffordMix13.

The second parameter is whether the split operation is enabled. Allows each instance to have a distinct increment, increasing the size from 64 bits to 128 bits. If split is not enabled then the opCall, seed, and skip operations will be shared provided the platform supports 64-bit atomic operations.

The third parameter is the default_increment. If the SplitMixEngine has a fixed increment this value will be used for each instance. If omitted this parameter defaults to DEFAULT_SPLITMIX_INCREMENT.

@nogc nothrow @safe

struct SplitMixEngine (

alias mixer

bool split_enabled = false

OptionalArgs...

) if (

(

__traits(compiles, ) ||

__traits(compiles, )

) &&

(

OptionalArgs.length < 1 ||

(

is(typeof(OptionalArgs[1]) == ulong) &&

OptionalArgs[1] != DEFAULT_SPLITMIX_INCREMENT

)

OptionalArgs.length < 2

) {

@nogc nothrow pure @safe

static if(OptionalArgs.length >= 1)

enum ulong default_increment;

@nogc nothrow pure @safe

static if(!(OptionalArgs.length >= 1))

enum ulong default_increment;

@nogc nothrow pure @safe

enum bool isRandomEngine;

@nogc nothrow pure @safe

enum ulong max;

@nogc nothrow pure @safe

enum uint period_pow2;

@nogc nothrow pure @safe

enum bool increment_specifiable;

@nogc nothrow pure @safe

ulong state;

@nogc nothrow pure @safe

static if(increment_specifiable)

ulong increment;

@nogc nothrow pure @safe

static if(!(increment_specifiable))

enum ulong increment;

alias gamma = increment;

this(ulong x0);

this(ulong x0, ulong increment);

ulong opCall();

typeof(this) split();

void skip(size_t n);

@nogc nothrow pure @safe

enum bool isUniformRandom;

@nogc nothrow pure @safe

enum ulong min;

@nogc nothrow pure @safe

enum bool empty;

ulong front [@property getter];

void popFront();

void seed(ulong x0);

void seed(ulong x0, ulong increment);

typeof(this) save [@property getter];

ulong opIndex(size_t n);

size_t popFrontN(size_t n);

alias popFrontExactly() = skip;

}

Constructors

this this(ulong x0): Constructs a SplitMixEngine generator seeded with x0.
this this(ulong x0, ulong increment): Constructs a SplitMixEngine generator seeded with x0 using the specified increment.

Postblit

A postblit is present on this object, but not explicitly documented in the source.

Members

Aliases

gamma alias gamma = increment: Either an enum or a settable value depending on whether increment_specifiable == true. This should always be an odd number. The paper refers to this as γ so it is aliased as gamma.
popFrontExactly alias popFrontExactly() = skip: Compatibility with Phobos library methods. Presents this RNG as an InputRange.

Functions

opCall ulong opCall(): Advances the random sequence.
opIndex ulong opIndex(size_t n)
popFront void popFront()
popFrontN size_t popFrontN(size_t n)
seed void seed(ulong x0)
void seed(ulong x0, ulong increment): Compatibility with Phobos library methods. Presents this RNG as an InputRange.
skip void skip(size_t n): Skip forward in the random sequence in O(1) time.
split typeof(this) split(): Produces a splitmix generator with a different counter-value and increment-value than the current generator. Only available when <a href="#.SplitMixEngine.increment_specifiable"> increment_specifiable == true</a>.

Properties

front ulong front [@property getter]
save typeof(this) save [@property getter]: Compatibility with Phobos library methods. Presents this RNG as an InputRange.

Variables

default_increment enum ulong default_increment;: Either DEFAULT_SPLITMIX_INCREMENT or the optional third argument of this template.
empty enum bool empty;: Compatibility with Phobos library methods. Presents this RNG as an InputRange.
increment ulong increment;
enum ulong increment;: Either an enum or a settable value depending on whether increment_specifiable == true. This should always be an odd number. The paper refers to this as γ so it is aliased as gamma.
increment_specifiable enum bool increment_specifiable;: Whether each instance can set its increment individually. Enables the split operation at the cost of increasing size from 64 bits to 128 bits.
isRandomEngine enum bool isRandomEngine;: Marks as a Mir random engine.
isUniformRandom enum bool isUniformRandom;: Compatibility with Phobos library methods. Presents this RNG as an InputRange.
max enum ulong max;: Largest generated value.
min enum ulong min;: Compatibility with Phobos library methods. Presents this RNG as an InputRange.
period_pow2 enum uint period_pow2;: Full period (2 ^^ 64).
state ulong state;: Current internal state of the generator.

Examples

//Can specify engine like this:
alias RNG1 = SplitMixEngine!staffordMix13;
alias RNG2 = SplitMixEngine!(fmix64!(0xbf58476d1ce4e5b9UL, 0x94d049bb133111ebUL, 30, 27, 31));

//Each way of writing it results in the same sequence.
assert(RNG1(1).opCall() == RNG2(1).opCall());

//However not each result's name is equally informative.
static assert(RNG1.stringof == `SplitMixEngine!(staffordMix13, false)`);
static assert(RNG2.stringof == `SplitMixEngine!(fmix64, false)`);//Doesn't include parameters of fmix64!

The OpenD Programming Language

SplitMixEngine

Constructors

Postblit

Members

Aliases

Functions

Properties

Variables

Examples

Meta

Source