Class wrapping convolution of two functions.

Class wrapping convolution of two functions: evaluation of \(\int f(x)g(x-t)dx\)

The convolution is performed by default using FFTW if it is available . One can pass optionally the range of the convolution (by default the first function range is used). Note that when using Discrete Fouriere Transform (as FFTW), it is a circular transform, so the functions should be approximatly zero at the end of the range. If they are significantly different than zero on one side (e.g. the left side) a spill over will occur on the other side (e.g right side). If no function range is given by default the function1 range + 10% is used One shoud use also a not too small number of points for the DFT (a minimum of 1000). By default 10000 points are used.

Definition at line 26 of file TF1Convolution.h.

Public Member Functions
	TF1Convolution (TF1 function1, TF1 function2, Bool_t useFFT=true)
	constructor from the two function pointer and a flag is using FFT More...

	TF1Convolution (TF1 function1, TF1 function2, Double_t xmin, Double_t xmax, Bool_t useFFT=true)
	constructor from the two function pointer and the convolution range More...

	TF1Convolution (TString formula, Double_t xmin=1., Double_t xmax=0., Bool_t useFFT=true)
	constructor from a formula expression as f1 * f2 where f1 and f2 are two functions known to ROOT More...

	TF1Convolution (TString formula1, TString formula2, Double_t xmin=1., Double_t xmax=0., Bool_t useFFT=true)
	constructor from 2 function names where f1 and f2 are two functions known to ROOT if the function names are not knwon to ROOT then a corresponding More...

void	SetParameters (Double_t *p)

void	SetParameters (Double_t p0, Double_t p1, Double_t p2=0., Double_t p3=0., Double_t p4=0., Double_t p5=0., Double_t p6=0., Double_t p7=0.)

void	SetRange (Double_t a, Double_t b)

void	SetExtraRange (Double_t percentage)

void	SetNofPointsFFT (Int_t n)

void	SetNumConv (Bool_t flag=true)

Int_t	GetNpar () const

Double_t	GetXmin () const

Double_t	GetXmax () const

const char *	GetParName (Int_t ipar) const

Double_t	operator() (Double_t t, Double_t p)

Private Member Functions
Double_t	EvalNumConv (Double_t t)
	perform numerical convolution could in principle cache the integral in a Graph as it is done for the FFTW More...

Double_t	EvalFFTConv (Double_t t)

void	InitializeDataMembers (TF1 function1, TF1 function2, Bool_t useFFT)
	use copy instead of Clone More...

void	MakeFFTConv ()
	perform the FFT of the two functions More...

Private Attributes
std::shared_ptr< TF1 >	fFunction1

std::shared_ptr< TF1 >	fFunction2

std::shared_ptr< TGraph >	fGraphConv

std::vector< Double_t >	fParams1

std::vector< Double_t >	fParams2

std::vector< TString >	fParNames

Double_t	fXmin

Double_t	fXmax

Int_t	fNofParams1

Int_t	fNofParams2

Int_t	fCstIndex

Int_t	fNofPoints

Bool_t	fFlagFFT

Bool_t	fFlagGraph

#include <TF1Convolution.h>

Constructor & Destructor Documentation

TF1Convolution::TF1Convolution	(	TF1 *	function1,
		TF1 *	function2,
		Bool_t	useFFT = `true`
	)

constructor from the two function pointer and a flag is using FFT

Definition at line 124 of file TF1Convolution.cxx.

TF1Convolution::TF1Convolution	(	TF1 *	function1,
		TF1 *	function2,
		Double_t	xmin,
		Double_t	xmax,
		Bool_t	useFFT = `true`
	)

constructor from the two function pointer and the convolution range

Definition at line 132 of file TF1Convolution.cxx.

TF1Convolution::TF1Convolution	(	TString	formula,
		Double_t	xmin = `1.`,
		Double_t	xmax = `0.`,
		Bool_t	useFFT = `true`
	)

constructor from a formula expression as f1 * f2 where f1 and f2 are two functions known to ROOT

Definition at line 144 of file TF1Convolution.cxx.

TF1Convolution::TF1Convolution	(	TString	formula1,
		TString	formula2,
		Double_t	xmin = `1.`,
		Double_t	xmax = `0.`,
		Bool_t	useFFT = `true`
	)

constructor from 2 function names where f1 and f2 are two functions known to ROOT if the function names are not knwon to ROOT then a corresponding

Definition at line 178 of file TF1Convolution.cxx.

Member Function Documentation

Double_t TF1Convolution::EvalFFTConv ( Double_t t )

private

Definition at line 270 of file TF1Convolution.cxx.

Referenced by operator()().

Double_t TF1Convolution::EvalNumConv ( Double_t t )

private

perform numerical convolution could in principle cache the integral in a Graph as it is done for the FFTW

Definition at line 284 of file TF1Convolution.cxx.

Referenced by EvalFFTConv(), and operator()().

Int_t TF1Convolution::GetNpar ( ) const

inline

Definition at line 67 of file TF1Convolution.h.

Referenced by fitConvolution(), and TFitEditor::GetFitFunction().

const char* TF1Convolution::GetParName ( Int_t ipar ) const

inline

Definition at line 70 of file TF1Convolution.h.

Referenced by TFitEditor::GetFitFunction(), and InitializeDataMembers().

Double_t TF1Convolution::GetXmax ( ) const

inline

Definition at line 69 of file TF1Convolution.h.

Referenced by SetRange().

Double_t TF1Convolution::GetXmin ( ) const

inline

Definition at line 68 of file TF1Convolution.h.

Referenced by SetRange().

void TF1Convolution::InitializeDataMembers	(	TF1 *	function1,
		TF1 *	function2,
		Bool_t	useFFT
	)

private

use copy instead of Clone

Definition at line 72 of file TF1Convolution.cxx.

Referenced by TF1Convolution().

void TF1Convolution::MakeFFTConv ( )

private

perform the FFT of the two functions

Definition at line 207 of file TF1Convolution.cxx.

Referenced by EvalFFTConv().

Double_t TF1Convolution::operator()	(	Double_t *	t,
		Double_t *	p
	)

Definition at line 304 of file TF1Convolution.cxx.

void TF1Convolution::SetExtraRange ( Double_t percentage )

Definition at line 377 of file TF1Convolution.cxx.

Referenced by SetRange().

void TF1Convolution::SetNofPointsFFT ( Int_t n )

Definition at line 315 of file TF1Convolution.cxx.

Referenced by fitConvolution().

void TF1Convolution::SetNumConv ( Bool_t flag = true )

inline

Definition at line 65 of file TF1Convolution.h.

void TF1Convolution::SetParameters ( Double_t * p )

Definition at line 325 of file TF1Convolution.cxx.

Referenced by operator()(), and SetParameters().

void TF1Convolution::SetParameters	(	Double_t	p0,
		Double_t	p1,
		Double_t	p2 = `0.`,
		Double_t	p3 = `0.`,
		Double_t	p4 = `0.`,
		Double_t	p5 = `0.`,
		Double_t	p6 = `0.`,
		Double_t	p7 = `0.`
	)