CRNG32 Struct Reference

Public Types
typedef unsigned	result_type

Public Member Functions
	CRNG32 (const unsigned s)
void	seed (const unsigned s)
CRNG32 &	index (const unsigned i)
unsigned	sample ()
unsigned	sample_range (const unsigned range)
unsigned	operator() ()
unsigned	hash (unsigned x)

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

Public Attributes
unsigned	n
unsigned	key

Detailed Description

Definition at line 12 of file crng.h.

Member Typedef Documentation

result_type

typedef unsigned CRNG32::result_type

Definition at line 39 of file crng.h.

Constructor & Destructor Documentation

CRNG32() [1/2]

CRNG32::CRNG32 ( )

inline

Definition at line 14 of file crng.h.

: n(), key() { seed(123451); }

CRNG32() [2/2]

CRNG32::CRNG32 ( const unsigned s )

inline

Definition at line 15 of file crng.h.

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

Member Function Documentation

seed()

void CRNG32::seed ( const unsigned s )

inline

Definition at line 16 of file crng.h.

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

index()

CRNG32 & CRNG32::index ( const unsigned i )

inline

Definition at line 18 of file crng.h.

{ n= i; return *this;}

sample()

unsigned CRNG32::sample ( )

inline

Definition at line 19 of file crng.h.

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

sample_range()

unsigned CRNG32::sample_range ( const unsigned range )

inline

Definition at line 21 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 CRNG32::operator() ( )

inline

Definition at line 36 of file crng.h.

{ return sample(); }

min()

constexpr unsigned CRNG32::min ( )

inlinestaticconstexpr

Definition at line 37 of file crng.h.

{ return 0; }

max()

constexpr unsigned CRNG32::max ( )

inlinestaticconstexpr

Definition at line 38 of file crng.h.

{ return ~unsigned(0); }

hash()

unsigned CRNG32::hash ( unsigned x )

inline

Definition at line 42 of file crng.h.

    {
        x ^= x >> 16;
        x *= 0x21f0aaad;
        x ^= x >> 15;
        x *= 0xd35a2d97;
        x ^= x >> 15;
        return x;
    }

Member Data Documentation

n

unsigned CRNG32::n

Definition at line 53 of file crng.h.

key

unsigned CRNG32::key

Definition at line 54 of file crng.h.

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

• src/gKit/crng.h