Threefry Struct Reference

Classes
struct	array2x32

Public Types
typedef unsigned	result_type

Public Member Functions
	Threefry (const uint64_t s)
	Threefry (const unsigned hi, const unsigned lo=0xacac820c)
void	seed (const unsigned hi, const unsigned lo=0xacac820c)
void	seed64 (const uint64_t s)
Threefry &	index (const uint64_t i)
unsigned	sample ()
unsigned	sample_range (const unsigned range)
unsigned	operator() ()

Static Public Member Functions
static constexpr unsigned	min ()
static constexpr unsigned	max ()

Detailed Description

Definition at line 215 of file rand123.h.

---

Class Documentation

Threefry::array2x32

struct Threefry::array2x32

Definition at line 261 of file rand123.h.

Class Members
unsigned	v[2]

Member Typedef Documentation

result_type

typedef unsigned Threefry::result_type

Definition at line 259 of file rand123.h.

Constructor & Destructor Documentation

Threefry() [1/3]

Threefry::Threefry ( )

inline

Definition at line 217 of file rand123.h.

: n(), key() { seed64(0xcf492074862957a3); }

Threefry() [2/3]

Threefry::Threefry ( const uint64_t s )

inline

Definition at line 218 of file rand123.h.

: n(), key() { seed64(s); }

Threefry() [3/3]

Threefry::Threefry ( const unsigned hi, const unsigned lo = 0xacac820c )

inline

Definition at line 219 of file rand123.h.

: n(), key() { seed(hi, lo); }

Member Function Documentation

seed()

void Threefry::seed ( const unsigned hi, const unsigned lo = 0xacac820c )

inline

Definition at line 221 of file rand123.h.

{ seed64( uint64_t(hi) << 32 | uint64_t(lo) ); }

seed64()

void Threefry::seed64 ( const uint64_t s )

inline

Definition at line 222 of file rand123.h.

    { 
        n= 0;
        key= { unsigned(s >> 32), unsigned(s) }; 
    }

index()

Threefry & Threefry::index ( const uint64_t i )

inline

Definition at line 228 of file rand123.h.

    { 
        n= i;
        return *this;
    }

sample()

unsigned Threefry::sample ( )

inline

Definition at line 234 of file rand123.h.

    { 
        n++;
        array2x32 ctr= { { unsigned(n >>32), unsigned(n) } }; 
        return threefry2x32<13>(ctr, key).v[0];
    }

sample_range()

unsigned Threefry::sample_range ( const unsigned range )

inline

Definition at line 241 of file rand123.h.

    {
        // Efficiently Generating a Number in a Range
        // cf http://www.pcg-random.org/posts/bounded-rands.html
        unsigned divisor= ((-range) / range) + 1; // (2^32) / range
        if(divisor == 0) return 0;
 
        while(true)
        {
            unsigned x= sample() / divisor;
            if(x < range) return x;
        }
    }

operator()()

unsigned Threefry::operator() ( )

inline

Definition at line 256 of file rand123.h.

{ return sample(); }

min()

constexpr unsigned Threefry::min ( )

inlinestaticconstexpr

Definition at line 257 of file rand123.h.

{ return 0; }

max()

constexpr unsigned Threefry::max ( )

inlinestaticconstexpr

Definition at line 258 of file rand123.h.

{ return ~unsigned(0); }

---

The documentation for this struct was generated from the following file:

• src/gKit/rand123.h