#include <Nsound/RngTausworthe.h>

Inheritance diagram for Nsound::RngTausworthe:

Public Member Functions
	RngTausworthe ()
	Default seed used is the number of seconds from unix epoch. More...

uint32	get ()
	Get a random number. More...

int32	get (const Nsound::int32 min, const Nsound::int32 max)
	Get a random float64 between min & max. More...

float64	get (const Nsound::float64 &min, const Nsound::float64 &max)
	Get a random float64 between min & max. More...

RngTausworthe &	operator= (const RngTausworthe &rhs)
	assignment operator More...

void	setSeed (Nsound::uint32 seed)
	Set the seed to use. More...

Private Attributes
Nsound::uint32	s1_

Nsound::uint32	s2_

Nsound::uint32	s3_

Detailed Description

An implementation of the Tausworthe random number algorithm found in the GNU Scientific Library.

Definition at line 45 of file RngTausworthe.h.

Constructor & Destructor Documentation

RngTausworthe::RngTausworthe ( )

Default seed used is the number of seconds from unix epoch.

Definition at line 40 of file RngTausworthe.cc.

References setSeed().

     :
     s1_(0),
     s2_(0),
     s3_(0)
 {
     setSeed(static_cast<uint32>(time(NULL)));
 }

Member Function Documentation

uint32 RngTausworthe::get ( )

virtual

Get a random number.

Implements Nsound::RandomNumberGenerator.

Definition at line 51 of file RngTausworthe.cc.

References s1_, s2_, s3_, and TAUSWORTHE.

Referenced by Nsound::FilterIIR::designKernel(), main(), and Nsound::Kernel::randomize().

 {
     #define MASK 0xffffffffUL
     #define TAUSWORTHE(s,a,b,c,d) (((s & c) << d) & MASK) ^ ((((s << a) & MASK) ^ s) >> b)
 
     s1_ = TAUSWORTHE(s1_, 13, 19, 4294967294UL, 12);
     s2_ = TAUSWORTHE(s2_,  2, 25, 4294967288UL,  4);
     s3_ = TAUSWORTHE(s3_,  3, 11, 4294967280UL, 17);
 
     uint32 r = s1_ ^ s2_ ^ s3_;
 
     return r;
 }

int32 RngTausworthe::get	(	const Nsound::int32	min,
		const Nsound::int32	max
	)

Get a random float64 between min & max.

Definition at line 67 of file RngTausworthe.cc.

 {
     return static_cast<int32>(
         get(
             static_cast<float64>(min),
             static_cast<float64>(max)));
 }

float64 RngTausworthe::get	(	const Nsound::float64 &	min,
		const Nsound::float64 &	max
	)

virtual

Get a random float64 between min & max.

Implements Nsound::RandomNumberGenerator.

Definition at line 79 of file RngTausworthe.cc.

 {
     float64 mag = abs(max - min);
     float64 d = mag * (static_cast<float64>(get()) / 4294967296.0) + min;
 
     return d;
 }

RngTausworthe & RngTausworthe::operator= ( const RngTausworthe & rhs )

assignment operator

Definition at line 92 of file RngTausworthe.cc.

References s1_, s2_, and s3_.

 {
     if(this == &rhs)
     {
         return *this;
     }
 
     s1_ = rhs.s1_;
     s2_ = rhs.s2_;
     s3_ = rhs.s3_;
 
     return * this;
 }

void RngTausworthe::setSeed ( Nsound::uint32 seed )

virtual

Set the seed to use.

Implements Nsound::RandomNumberGenerator.

Definition at line 108 of file RngTausworthe.cc.

References LCG, s1_, s2_, and s3_.

Referenced by RngTausworthe().

 {
     uint32 s = seed;
 
     // Set default seed.
     if(s == 0)
     {
         s = 1;
     }
 
     #define LCG(n) ((69069 * n) & 0xffffffffUL)
     s1_ = LCG(s);
     s2_ = LCG(s1_);
     s3_ = LCG(s2_);
 
     // "warm it up"
     get();
     get();
     get();
     get();
     get();
     get();
 }