RooQuasiRandomGenerator Class Reference

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.

Definition at line 21 of file RooQuasiRandomGenerator.h.

Public Types
enum	{ MaxDimension = 12, NBits = 31, MaxDegree = 50, MaxPrimitiveDegree = 5 }

Public Member Functions
	RooQuasiRandomGenerator ()
	Perform one-time initialization of our static coefficient array if necessary and initialize our workspace. More...
virtual	~RooQuasiRandomGenerator ()
	Destructor. More...
void	reset ()
	Reset the workspace to its initial state. More...
Bool_t	generate (UInt_t dimension, Double_t vector[])
	Generate the next number in the sequence for the specified dimension. More...

Protected Member Functions
void	calculateCoefs (UInt_t dimension)
	Calculate the coefficients for the given number of dimensions. More...
void	calculateV (const int px[], int px_degree, int pb[], int *pb_degree, int v[], int maxv)
	Internal function. More...
void	polyMultiply (const int pa[], int pa_degree, const int pb[], int pb_degree, int pc[], int *pc_degree)
	Internal function. More...
Int_t	add (Int_t x, Int_t y) const
Int_t	mul (Int_t x, Int_t y) const
Int_t	sub (Int_t x, Int_t y) const

Private Attributes
Int_t *	_nextq
Int_t	_sequenceCount

Static Private Attributes
static Bool_t	_coefsCalculated = kFALSE
static Int_t	_cj [NBits][MaxDimension]
static const Int_t	_primitivePoly [MaxDimension+1][MaxPrimitiveDegree+1]
static const Int_t	_polyDegree [MaxDimension+1]

#include <RooQuasiRandomGenerator.h>

Member Enumeration Documentation

anonymous enum

Enumerator
MaxDimension
NBits
MaxDegree
MaxPrimitiveDegree

Definition at line 27 of file RooQuasiRandomGenerator.h.

Constructor & Destructor Documentation

RooQuasiRandomGenerator::RooQuasiRandomGenerator

(

)

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

Definition at line 52 of file RooQuasiRandomGenerator.cxx.

RooQuasiRandomGenerator::~RooQuasiRandomGenerator ( )

virtual

Destructor.

Definition at line 67 of file RooQuasiRandomGenerator.cxx.

Member Function Documentation

Int_t RooQuasiRandomGenerator::add ( Int_t  x, Int_t  y  ) const

inlineprotected

Definition at line 35 of file RooQuasiRandomGenerator.h.

Referenced by sub().

void RooQuasiRandomGenerator::calculateCoefs ( UInt_t  dimension )

protected

Calculate the coefficients for the given number of dimensions.

Definition at line 127 of file RooQuasiRandomGenerator.cxx.

void RooQuasiRandomGenerator::calculateV ( const int  px[], int  px_degree, int  pb[], int *  pb_degree, int  v[], int  maxv  )

protected

Internal function.

Definition at line 205 of file RooQuasiRandomGenerator.cxx.

Bool_t RooQuasiRandomGenerator::generate	(	UInt_t	dimension,
		Double_t	vector[]
	)

Generate the next number in the sequence for the specified dimension.

The maximum dimension supported is 12.

Definition at line 87 of file RooQuasiRandomGenerator.cxx.

Referenced by RooRandom::quasi().

Int_t RooQuasiRandomGenerator::mul ( Int_t  x, Int_t  y  ) const

inlineprotected

Definition at line 36 of file RooQuasiRandomGenerator.h.

void RooQuasiRandomGenerator::polyMultiply ( const int  pa[], int  pa_degree, const int  pb[], int  pb_degree, int  pc[], int *  pc_degree  )

protected

Internal function.

Definition at line 297 of file RooQuasiRandomGenerator.cxx.

void RooQuasiRandomGenerator::reset

(

)

Reset the workspace to its initial state.

Definition at line 76 of file RooQuasiRandomGenerator.cxx.

Int_t RooQuasiRandomGenerator::sub ( Int_t  x, Int_t  y  ) const

inlineprotected

Definition at line 37 of file RooQuasiRandomGenerator.h.

Member Data Documentation

Int_t RooQuasiRandomGenerator::_cj

staticprivate

Definition at line 43 of file RooQuasiRandomGenerator.h.

Bool_t RooQuasiRandomGenerator::_coefsCalculated = kFALSE

staticprivate

Definition at line 42 of file RooQuasiRandomGenerator.h.

Int_t* RooQuasiRandomGenerator::_nextq

private

Definition at line 39 of file RooQuasiRandomGenerator.h.

const Int_t RooQuasiRandomGenerator::_polyDegree

staticprivate

Initial value:

=
{
  0, 1, 1, 2, 3, 3, 4, 4, 4, 5, 5, 5, 5
}

Definition at line 45 of file RooQuasiRandomGenerator.h.

const Int_t RooQuasiRandomGenerator::_primitivePoly

staticprivate

Initial value:

=
{
  { 1, 0, 0, 0, 0, 0 },  
  { 0, 1, 0, 0, 0, 0 },  
  { 1, 1, 0, 0, 0, 0 },  
  { 1, 1, 1, 0, 0, 0 },  
  { 1, 1, 0, 1, 0, 0 },  
  { 1, 0, 1, 1, 0, 0 },  
  { 1, 1, 0, 0, 1, 0 },  
  { 1, 0, 0, 1, 1, 0 },  
  { 1, 1, 1, 1, 1, 0 },  
  { 1, 0, 1, 0, 0, 1 },  
  { 1, 0, 0, 1, 0, 1 },  
  { 1, 1, 1, 1, 0, 1 },  
  { 1, 1, 1, 0, 1, 1 }   
}

Definition at line 44 of file RooQuasiRandomGenerator.h.

Int_t RooQuasiRandomGenerator::_sequenceCount

private

Definition at line 40 of file RooQuasiRandomGenerator.h.

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The documentation for this class was generated from the following files:

• roofit/roofitcore/inc/RooQuasiRandomGenerator.h
• roofit/roofitcore/src/RooQuasiRandomGenerator.cxx