ROOT   Reference Guide
TF1Convolution Class Reference

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 Fourier Transform (as FFTW), it is a circular transform, so the functions should be approximately 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 should 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 20 of file TF1Convolution.h.

## Public Member Functions

TF1Convolution ()
constructor without arguments. More...

TF1Convolution (const TF1Convolution &conv)
Copy constructor (necessary to hold unique_ptr as member variable). More...

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. More...

~TF1Convolution () override

void Copy (TObject &obj) const override
Copy this to obj. More...

Int_t GetNpar () const

const char * GetParName (Int_t ipar) const

void GetRange (Double_t &a, Double_t &b) const
Get the range used for the convolution. More...

Double_t GetXmax () const

Double_t GetXmin () const

TClassIsA () const override

Double_t operator() (const Double_t *x, const Double_t *p) override
Used in TF1 when doing the fit, will be evaluated at each point. More...

TF1Convolutionoperator= (const TF1Convolution &rhs)
Operator =. More...

void SetExtraRange (Double_t percentage)
Set the fraction of extra range used when doing an FFT convolution. More...

void SetNofPointsFFT (Int_t n)
Set the number of points used for the FFT convolution. More...

void SetNumConv (Bool_t flag=true)

void SetParameters (const Double_t *params) override
Set the vector of parameters p for the convolution function g(x,p) = f1 * f2. More...

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.)
Set the parameter values for the convolution function. More...

void SetRange (Double_t a, Double_t b) override
Set the actual range used for the convolution. More...

void Streamer (TBuffer &) override
Stream an object of class TObject. More...

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

void Update () override
Update the two component functions of the convolution. More...

Public Member Functions inherited from TF1AbsComposition
~TF1AbsComposition () override

void Copy (TObject &obj) const override=0
Copy this to obj. More...

TClassIsA () const override

virtual double operator() (const Double_t *x, const Double_t *p)=0

virtual void SetParameters (const Double_t *params)=0

virtual void SetRange (Double_t a, Double_t b)=0

void Streamer (TBuffer &) override
Stream an object of class TObject. More...

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

virtual void Update ()=0

Public Member Functions inherited from TObject
TObject ()
TObject constructor. More...

TObject (const TObject &object)
TObject copy ctor. More...

virtual ~TObject ()
TObject destructor. More...

void AbstractMethod (const char *method) const
Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...

Append graphics object to current pad. More...

virtual void Browse (TBrowser *b)
Browse object. May be overridden for another default action. More...

ULong_t CheckedHash ()
Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object. More...

virtual const char * ClassName () const
Returns name of class to which the object belongs. More...

virtual void Clear (Option_t *="")

virtual TObjectClone (const char *newname="") const
Make a clone of an object using the Streamer facility. More...

virtual Int_t Compare (const TObject *obj) const
Compare abstract method. More...

virtual void Copy (TObject &object) const
Copy this to obj. More...

virtual void Delete (Option_t *option="")
Delete this object. More...

virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
Computes distance from point (px,py) to the object. More...

virtual void Draw (Option_t *option="")
Default Draw method for all objects. More...

virtual void DrawClass () const
Draw class inheritance tree of the class to which this object belongs. More...

virtual TObjectDrawClone (Option_t *option="") const
Draw a clone of this object in the current selected pad with: gROOT->SetSelectedPad(c1). More...

virtual void Dump () const
Dump contents of object on stdout. More...

virtual void Error (const char *method, const char *msgfmt,...) const
Issue error message. More...

virtual void Execute (const char *method, const char *params, Int_t *error=nullptr)
Execute method on this object with the given parameter string, e.g. More...

virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=nullptr)
Execute method on this object with parameters stored in the TObjArray. More...

virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
Execute action corresponding to an event at (px,py). More...

virtual void Fatal (const char *method, const char *msgfmt,...) const
Issue fatal error message. More...

virtual TObjectFindObject (const char *name) const
Must be redefined in derived classes. More...

virtual TObjectFindObject (const TObject *obj) const
Must be redefined in derived classes. More...

virtual Option_tGetDrawOption () const
Get option used by the graphics system to draw this object. More...

virtual const char * GetIconName () const
Returns mime type name of object. More...

virtual const char * GetName () const
Returns name of object. More...

virtual char * GetObjectInfo (Int_t px, Int_t py) const
Returns string containing info about the object at position (px,py). More...

virtual Option_tGetOption () const

virtual const char * GetTitle () const
Returns title of object. More...

virtual UInt_t GetUniqueID () const
Return the unique object id. More...

virtual Bool_t HandleTimer (TTimer *timer)
Execute action in response of a timer timing out. More...

virtual ULong_t Hash () const
Return hash value for this object. More...

Bool_t HasInconsistentHash () const
Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e. More...

virtual void Info (const char *method, const char *msgfmt,...) const
Issue info message. More...

virtual Bool_t InheritsFrom (const char *classname) const
Returns kTRUE if object inherits from class "classname". More...

virtual Bool_t InheritsFrom (const TClass *cl) const
Returns kTRUE if object inherits from TClass cl. More...

virtual void Inspect () const
Dump contents of this object in a graphics canvas. More...

void InvertBit (UInt_t f)

virtual TClassIsA () const

Bool_t IsDestructed () const
IsDestructed. More...

virtual Bool_t IsEqual (const TObject *obj) const
Default equal comparison (objects are equal if they have the same address in memory). More...

virtual Bool_t IsFolder () const
Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...

R__ALWAYS_INLINE Bool_t IsOnHeap () const

virtual Bool_t IsSortable () const

R__ALWAYS_INLINE Bool_t IsZombie () const

virtual void ls (Option_t *option="") const
The ls function lists the contents of a class on stdout. More...

void MayNotUse (const char *method) const
Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More...

virtual Bool_t Notify ()
This method must be overridden to handle object notification. More...

void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
Use this method to declare a method obsolete. More...

void operator delete (void *ptr)
Operator delete. More...

void operator delete[] (void *ptr)
Operator delete []. More...

void * operator new (size_t sz)

void * operator new (size_t sz, void *vp)

void * operator new[] (size_t sz)

void * operator new[] (size_t sz, void *vp)

TObjectoperator= (const TObject &rhs)
TObject assignment operator. More...

virtual void Paint (Option_t *option="")
This method must be overridden if a class wants to paint itself. More...

virtual void Pop ()
Pop on object drawn in a pad to the top of the display list. More...

virtual void Print (Option_t *option="") const
This method must be overridden when a class wants to print itself. More...

virtual Int_t Read (const char *name)
Read contents of object with specified name from the current directory. More...

virtual void RecursiveRemove (TObject *obj)
Recursively remove this object from a list. More...

void ResetBit (UInt_t f)

virtual void SaveAs (const char *filename="", Option_t *option="") const
Save this object in the file specified by filename. More...

virtual void SavePrimitive (std::ostream &out, Option_t *option="")
Save a primitive as a C++ statement(s) on output stream "out". More...

void SetBit (UInt_t f)

void SetBit (UInt_t f, Bool_t set)
Set or unset the user status bits as specified in f. More...

virtual void SetDrawOption (Option_t *option="")
Set drawing option for object. More...

virtual void SetUniqueID (UInt_t uid)
Set the unique object id. More...

virtual void Streamer (TBuffer &)
Stream an object of class TObject. More...

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

virtual void SysError (const char *method, const char *msgfmt,...) const
Issue system error message. More...

R__ALWAYS_INLINE Bool_t TestBit (UInt_t f) const

Int_t TestBits (UInt_t f) const

virtual void UseCurrentStyle ()
Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More...

virtual void Warning (const char *method, const char *msgfmt,...) const
Issue warning message. More...

virtual Int_t Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0)
Write this object to the current directory. More...

virtual Int_t Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0) const
Write this object to the current directory. More...

## Static Public Member Functions

static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

static Double_t SetDefaultExtraRange (Double_t percentage)
Set the default extra range fraction used when doing a FFT convolution. More...

Static Public Member Functions inherited from TF1AbsComposition
static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

Static Public Member Functions inherited from TObject
static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

static Longptr_t GetDtorOnly ()
Return destructor only flag. More...

static Bool_t GetObjectStat ()
Get status of object stat flag. More...

static void SetDtorOnly (void *obj)
Set destructor only flag. More...

static void SetObjectStat (Bool_t stat)
Turn on/off tracking of objects in the TObjectTable. More...

## Private Member Functions

Double_t EvalFFTConv (Double_t t)
Perform FFT convolution. More...

Double_t EvalNumConv (Double_t t)
Perform numerical convolution. More...

void InitializeDataMembers (TF1 *function1, TF1 *function2, Bool_t useFFT)
Internal function to initialize data members. More...

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

## Private Attributes

Int_t fCstIndex
Index of the constant parameter f the first function. More...

Bool_t fFlagFFT
Choose FFT or numerical convolution. More...

Bool_t fFlagGraph = false
! Tells if the graph is already done or not More...

std::unique_ptr< TF1fFunction1
First function to be convolved. More...

std::unique_ptr< TF1fFunction2
Second function to be convolved. More...

std::unique_ptr< TGraphfGraphConv
! Graph of the convolution More...

Int_t fNofParams1

Int_t fNofParams2

Int_t fNofPoints
Number of point for FFT array. More...

std::vector< Double_tfParams1

std::vector< Double_tfParams2

std::vector< TStringfParNames
Parameters' names. More...

Double_t fXmax
Maximal bound of the range of the convolution. More...

Double_t fXmin
Minimal bound of the range of the convolution. More...

## Static Private Attributes

static Double_t fgExtraRangeFraction = 0.1
! Additional default fraction of the range used for FFT convolution More...

Public Types inherited from TObject
enum  {
kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 ,
}

enum  { kSingleKey = (1ULL << ( 0 )) , kOverwrite = (1ULL << ( 1 )) , kWriteDelete = (1ULL << ( 2 )) }

enum  EDeprecatedStatusBits { kObjInCanvas = (1ULL << ( 3 )) }

enum  EStatusBits {
kCanDelete = (1ULL << ( 0 )) , kMustCleanup = (1ULL << ( 3 )) , kIsReferenced = (1ULL << ( 4 )) , kHasUUID = (1ULL << ( 5 )) ,
kCannotPick = (1ULL << ( 6 )) , kNoContextMenu = (1ULL << ( 8 )) , kInvalidObject = (1ULL << ( 13 ))
}

Protected Types inherited from TObject
enum  { kOnlyPrepStep = (1ULL << ( 3 )) }

Protected Member Functions inherited from TObject
virtual void DoError (int level, const char *location, const char *fmt, va_list va) const
Interface to ErrorHandler (protected). More...

void MakeZombie ()

#include <TF1Convolution.h>

Inheritance diagram for TF1Convolution:
[legend]

## ◆ TF1Convolution() [1/6]

 TF1Convolution::TF1Convolution ( )

constructor without arguments.

Definition at line 135 of file TF1Convolution.cxx.

## ◆ TF1Convolution() [2/6]

 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 143 of file TF1Convolution.cxx.

## ◆ TF1Convolution() [3/6]

 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 151 of file TF1Convolution.cxx.

## ◆ TF1Convolution() [4/6]

 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 167 of file TF1Convolution.cxx.

## ◆ TF1Convolution() [5/6]

 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 known to ROOT, tries to interpret them as TFormula.

Definition at line 207 of file TF1Convolution.cxx.

## ◆ TF1Convolution() [6/6]

 TF1Convolution::TF1Convolution ( const TF1Convolution & conv )

Copy constructor (necessary to hold unique_ptr as member variable).

Definition at line 239 of file TF1Convolution.cxx.

## ◆ ~TF1Convolution()

 TF1Convolution::~TF1Convolution ( )
inlineoverride

Definition at line 56 of file TF1Convolution.h.

## ◆ Class()

 static TClass * TF1Convolution::Class ( )
static
Returns
TClass describing this class

## ◆ Class_Name()

 static const char * TF1Convolution::Class_Name ( )
static
Returns
Name of this class

## ◆ Class_Version()

 static constexpr Version_t TF1Convolution::Class_Version ( )
inlinestaticconstexpr
Returns
Version of this class

Definition at line 80 of file TF1Convolution.h.

## ◆ Copy()

 void TF1Convolution::Copy ( TObject & object ) const
overridevirtual

Copy this to obj.

Implements TF1AbsComposition.

Definition at line 502 of file TF1Convolution.cxx.

## ◆ DeclFileName()

 static const char * TF1Convolution::DeclFileName ( )
inlinestatic
Returns
Name of the file containing the class declaration

Definition at line 80 of file TF1Convolution.h.

## ◆ EvalFFTConv()

 Double_t TF1Convolution::EvalFFTConv ( Double_t t )
private

Perform FFT convolution.

Definition at line 328 of file TF1Convolution.cxx.

## ◆ EvalNumConv()

 Double_t TF1Convolution::EvalNumConv ( Double_t t )
private

Perform numerical convolution.

Definition at line 343 of file TF1Convolution.cxx.

## ◆ GetNpar()

 Int_t TF1Convolution::GetNpar ( ) const
inline

Definition at line 68 of file TF1Convolution.h.

## ◆ GetParName()

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

Definition at line 71 of file TF1Convolution.h.

## ◆ GetRange()

 void TF1Convolution::GetRange ( Double_t & a, Double_t & b ) const

Get the range used for the convolution.

Definition at line 485 of file TF1Convolution.cxx.

## ◆ GetXmax()

 Double_t TF1Convolution::GetXmax ( ) const
inline

Definition at line 70 of file TF1Convolution.h.

## ◆ GetXmin()

 Double_t TF1Convolution::GetXmin ( ) const
inline

Definition at line 69 of file TF1Convolution.h.

## ◆ InitializeDataMembers()

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

Internal function to initialize data members.

Definition at line 71 of file TF1Convolution.cxx.

## ◆ IsA()

 TClass * TF1Convolution::IsA ( ) const
inlineoverridevirtual
Returns
TClass describing current object

Reimplemented from TF1AbsComposition.

Definition at line 80 of file TF1Convolution.h.

## ◆ MakeFFTConv()

 void TF1Convolution::MakeFFTConv ( )
private

Perform the FFT of the two functions.

Definition at line 257 of file TF1Convolution.cxx.

## ◆ operator()()

 Double_t TF1Convolution::operator() ( const Double_t * x, const Double_t * p )
overridevirtual

Used in TF1 when doing the fit, will be evaluated at each point.

Implements TF1AbsComposition.

Definition at line 365 of file TF1Convolution.cxx.

## ◆ operator=()

 TF1Convolution & TF1Convolution::operator= ( const TF1Convolution & rhs )

Operator =.

Definition at line 247 of file TF1Convolution.cxx.

## ◆ SetDefaultExtraRange()

 Double_t TF1Convolution::SetDefaultExtraRange ( Double_t fraction )
static

Set the default extra range fraction used when doing a FFT convolution.

By default the value is 0.1 (10%). The function return the previous default defined value.

Definition at line 475 of file TF1Convolution.cxx.

## ◆ SetExtraRange()

 void TF1Convolution::SetExtraRange ( Double_t percentage )

Set the fraction of extra range used when doing an FFT convolution.

The extra range is often needed to avoid mirroring effect of the resulting convolution function at the borders. By default an extra range of 0.1 is used.

Definition at line 436 of file TF1Convolution.cxx.

## ◆ SetNofPointsFFT()

 void TF1Convolution::SetNofPointsFFT ( Int_t n )

Set the number of points used for the FFT convolution.

Definition at line 380 of file TF1Convolution.cxx.

## ◆ SetNumConv()

 void TF1Convolution::SetNumConv ( Bool_t flag = true )
inline

Definition at line 64 of file TF1Convolution.h.

## ◆ SetParameters() [1/2]

 void TF1Convolution::SetParameters ( const Double_t * params )
overridevirtual

Set the vector of parameters p for the convolution function g(x,p) = f1 * f2.

Implements TF1AbsComposition.

Definition at line 391 of file TF1Convolution.cxx.

## ◆ SetParameters() [2/2]

 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. )

Set the parameter values for the convolution function.

Definition at line 423 of file TF1Convolution.cxx.

## ◆ SetRange()

 void TF1Convolution::SetRange ( Double_t a, Double_t b )
overridevirtual

Set the actual range used for the convolution.

In case a or b are -inf or +inf and FFT convolution is used, then the range of the first function will be used and extended by the default extra range fraction.

Implements TF1AbsComposition.

Definition at line 450 of file TF1Convolution.cxx.

## ◆ Streamer()

 void TF1Convolution::Streamer ( TBuffer & R__b )
overridevirtual

Stream an object of class TObject.

Reimplemented from TF1AbsComposition.

## ◆ StreamerNVirtual()

 void TF1Convolution::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )
inline

Definition at line 80 of file TF1Convolution.h.

## ◆ Update()

 void TF1Convolution::Update ( )
overridevirtual

Update the two component functions of the convolution.

Implements TF1AbsComposition.

Definition at line 494 of file TF1Convolution.cxx.

## ◆ fCstIndex

 Int_t TF1Convolution::fCstIndex
private

Index of the constant parameter f the first function.

Definition at line 34 of file TF1Convolution.h.

## ◆ fFlagFFT

 Bool_t TF1Convolution::fFlagFFT
private

Choose FFT or numerical convolution.

Definition at line 36 of file TF1Convolution.h.

## ◆ fFlagGraph

 Bool_t TF1Convolution::fFlagGraph = false
private

! Tells if the graph is already done or not

Definition at line 37 of file TF1Convolution.h.

## ◆ fFunction1

 std::unique_ptr TF1Convolution::fFunction1
private

First function to be convolved.

Definition at line 21 of file TF1Convolution.h.

## ◆ fFunction2

 std::unique_ptr TF1Convolution::fFunction2
private

Second function to be convolved.

Definition at line 22 of file TF1Convolution.h.

## ◆ fgExtraRangeFraction

 Double_t TF1Convolution::fgExtraRangeFraction = 0.1
staticprivate

! Additional default fraction of the range used for FFT convolution

Definition at line 38 of file TF1Convolution.h.

## ◆ fGraphConv

 std::unique_ptr TF1Convolution::fGraphConv
private

! Graph of the convolution

Definition at line 23 of file TF1Convolution.h.

## ◆ fNofParams1

 Int_t TF1Convolution::fNofParams1
private

Definition at line 32 of file TF1Convolution.h.

## ◆ fNofParams2

 Int_t TF1Convolution::fNofParams2
private

Definition at line 33 of file TF1Convolution.h.

## ◆ fNofPoints

 Int_t TF1Convolution::fNofPoints
private

Number of point for FFT array.

Definition at line 35 of file TF1Convolution.h.

## ◆ fParams1

 std::vector< Double_t > TF1Convolution::fParams1
private

Definition at line 25 of file TF1Convolution.h.

## ◆ fParams2

 std::vector< Double_t > TF1Convolution::fParams2
private

Definition at line 26 of file TF1Convolution.h.

## ◆ fParNames

 std::vector< TString > TF1Convolution::fParNames
private

Parameters' names.

Definition at line 28 of file TF1Convolution.h.

## ◆ fXmax

 Double_t TF1Convolution::fXmax
private

Maximal bound of the range of the convolution.

Definition at line 31 of file TF1Convolution.h.

## ◆ fXmin

 Double_t TF1Convolution::fXmin
private

Minimal bound of the range of the convolution.

Definition at line 30 of file TF1Convolution.h.

Libraries for TF1Convolution:
[legend]

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