CRNG64 Struct Reference

Public Types
typedef unsigned	result_type

Public Member Functions
	CRNG64 (const uint64_t s)
	CRNG64 (const unsigned hi, const unsigned lo=0x40ba6a95)
void	seed (const unsigned hi, const unsigned lo=0x40ba6a95)
void	seed64 (const uint64_t s)
CRNG64 &	index (const uint64_t i)
unsigned	sample ()
unsigned	sample_range (const unsigned range)
unsigned	operator() ()
unsigned	hash (uint64_t v)

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

Public Attributes
uint64_t	n
uint64_t	key

Detailed Description

Definition at line 60 of file crng.h.

Member Typedef Documentation

result_type

typedef unsigned CRNG64::result_type

Definition at line 90 of file crng.h.

Constructor & Destructor Documentation

CRNG64() [1/3]

CRNG64::CRNG64 ( )

inline

Definition at line 62 of file crng.h.

: n(), key() { seed64(0xc58efd154ce32f6d); }

CRNG64() [2/3]

CRNG64::CRNG64 ( const uint64_t s )

inline

Definition at line 63 of file crng.h.

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

CRNG64() [3/3]

CRNG64::CRNG64 ( const unsigned hi, const unsigned lo = 0x40ba6a95 )

inline

Definition at line 64 of file crng.h.

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

Member Function Documentation

seed()

void CRNG64::seed ( const unsigned hi, const unsigned lo = 0x40ba6a95 )

inline

Definition at line 66 of file crng.h.

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

seed64()

void CRNG64::seed64 ( const uint64_t s )

inline

Definition at line 67 of file crng.h.

{ n= 0; key= (s << 1) | 1; }

index()

CRNG64 & CRNG64::index ( const uint64_t i )

inline

Definition at line 69 of file crng.h.

{ n= i; return *this;}

sample()

unsigned CRNG64::sample ( )

inline

Definition at line 70 of file crng.h.

{ return hash(++n * key); }

sample_range()

unsigned CRNG64::sample_range ( const unsigned range )

inline

Definition at line 72 of file crng.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 CRNG64::operator() ( )

inline

Definition at line 87 of file crng.h.

{ return sample(); }

min()

constexpr unsigned CRNG64::min ( )

inlinestaticconstexpr

Definition at line 88 of file crng.h.

{ return 0; }

max()

constexpr unsigned CRNG64::max ( )

inlinestaticconstexpr

Definition at line 89 of file crng.h.

{ return ~unsigned(0); }

hash()

unsigned CRNG64::hash ( uint64_t v )

inline

Definition at line 92 of file crng.h.

    { 
        v ^= (v >> 31);
        v *= 0x7fb5d329728ea185;
        v ^= (v >> 27);
        v *= 0x81dadef4bc2dd44d;
        v ^= (v >> 33);
        return v;
    }

Member Data Documentation

n

uint64_t CRNG64::n

Definition at line 103 of file crng.h.

key

uint64_t CRNG64::key

Definition at line 104 of file crng.h.

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

• src/gKit/crng.h