class RooQuasiRandomGenerator

This class generates the quasi-random (aka "low discrepancy") sequence for dimensions up to 12 using the Niederreiter base 2 algorithm described in Bratley, Fox, Niederreiter, ACM Trans. Model. Comp. Sim. 2, 195 (1992). This implementation was adapted from the 0.9 beta release of the GNU scientific library. Quasi-random number sequences are useful for improving the convergence of a Monte Carlo integration.

Function Members (Methods)

public:

	RooQuasiRandomGenerator()
	RooQuasiRandomGenerator(const RooQuasiRandomGenerator&)
virtual	~RooQuasiRandomGenerator()
static TClass*	Class()
Bool_t	generate(UInt_t dimension, Double_t* vector)
virtual TClass*	IsA() const
RooQuasiRandomGenerator&	operator=(const RooQuasiRandomGenerator&)
void	reset()
virtual void	ShowMembers(TMemberInspector&)
virtual void	Streamer(TBuffer&)
void	StreamerNVirtual(TBuffer& ClassDef_StreamerNVirtual_b)

protected:

Int_t	add(Int_t x, Int_t y) const
void	calculateCoefs(UInt_t dimension)
void	calculateV(const int* px, int px_degree, int* pb, int* pb_degree, int* v, int maxv)
Int_t	mul(Int_t x, Int_t y) const
void	polyMultiply(const int* pa, int pa_degree, const int* pb, int pb_degree, int* pc, int* pc_degree)
Int_t	sub(Int_t x, Int_t y) const

Data Members

public:

enum {	MaxDimension
	NBits
	MaxDegree
	MaxPrimitiveDegree
};

private:

static Int_t	_cj[31][12]
static Bool_t	_coefsCalculated
Int_t*	_nextq
static const Int_t	_polyDegree[13]
static const Int_t	_primitivePoly[13][6]
Int_t	_sequenceCount

Class Charts

Inheritance Inherited Members Includes Libraries

Function documentation

RooQuasiRandomGenerator()

 Perform one-time initialization of our static coefficient array if necessary
 and initialize our workspace.

~RooQuasiRandomGenerator()

 Destructor

void reset()

 Reset the workspace to its initial state.

Bool_t generate(UInt_t dimension, Double_t* vector)

 Generate the next number in the sequence for the specified dimension.
 The maximum dimension supported is 12.

void calculateCoefs(UInt_t dimension)

 Calculate the coefficients for the given number of dimensions

void calculateV(const int* px, int px_degree, int* pb, int* pb_degree, int* v, int maxv)

 Internal function

void polyMultiply(const int* pa, int pa_degree, const int* pb, int pb_degree, int* pc, int* pc_degree)

 Internal function

RooQuasiRandomGenerator()

Int_t add(Int_t x, Int_t y) const

 Z_2 field operations

{ return (x+y)%2; }

Int_t mul(Int_t x, Int_t y) const

{ return (x*y)%2; }

Int_t sub(Int_t x, Int_t y) const

{ return add(x,y); }