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TFFTRealComplex Class Reference

One of the interface classes to the FFTW package, can be used directly or via the TVirtualFFT class.

Only the basic interface of FFTW is implemented.

Computes a real input/complex output discrete Fourier transform in 1 or more dimensions. However, only out-of-place transforms are now supported for transforms in more than 1 dimension. For detailed information about the computed transforms, please refer to the FFTW manual

How to use it:

1. Create an instance of TFFTRealComplex - this will allocate input and output arrays (unless an in-place transform is specified)
2. Run the Init() function with the desired flags and settings (see function comments for possible kind parameters)
3. Set the data (via SetPoints()or SetPoint() functions)
4. Run the Transform() function
5. Get the output (via GetPoints() or GetPoint() functions)
6. Repeat steps 3)-5) as needed For a transform of the same size, but with different flags, rerun the Init() function and continue with steps 3)-5)

NOTE:

1. running Init() function will overwrite the input array! Don't set any data before running the Init() function
2. FFTW computes unnormalized transform, so doing a transform followed by its inverse will lead to the original array scaled by the transform size

Definition at line 20 of file TFFTRealComplex.h.

## Public Member Functions

TFFTRealComplex ()
default

TFFTRealComplex (Int_t n, Bool_t inPlace)
For 1d transforms Allocates memory for the input array, and, if inPlace = kFALSE, for the output array.

TFFTRealComplex (Int_t ndim, Int_t *n, Bool_t inPlace)
For ndim-dimensional transforms Second argument contains sizes of the transform in each dimension.

~TFFTRealComplex () override
Destroys the data arrays and the plan.

Int_tGetN () const override

Int_t GetNdim () const override

void GetPointComplex (const Int_t *ipoint, Double_t &re, Double_t &im, Bool_t fromInput=kFALSE) const override
For multidimensional transforms.

void GetPointComplex (Int_t ipoint, Double_t &re, Double_t &im, Bool_t fromInput=kFALSE) const override
Returns the point #ipoint.

Double_t GetPointReal (const Int_t *ipoint, Bool_t fromInput=kFALSE) const override
Returns the real part of the point #ipoint from the output or the point #ipoint from the input.

Double_t GetPointReal (Int_t ipoint, Bool_t fromInput=kFALSE) const override
Returns the real part of the point #ipoint from the output or the point #ipoint from the input.

void GetPoints (Double_t *data, Bool_t fromInput=kFALSE) const override
Fills the array data with the computed transform.

void GetPointsComplex (Double_t *data, Bool_t fromInput=kFALSE) const override
Fills the argument arrays with the real and imaginary parts of the computed transform.

void GetPointsComplex (Double_t *re, Double_t *im, Bool_t fromInput=kFALSE) const override
Fills the argument arrays with the real and imaginary parts of the computed transform.

Double_tGetPointsReal (Bool_t fromInput=kFALSE) const override
Returns the input array// One of the interface classes to the FFTW package, can be used directly or via the TVirtualFFT class.

Int_t GetSign () const override

virtual Int_t GetSize () const

Option_tGetTransformFlag () const override

Option_tGetType () const override

void Init (Option_t *flags, Int_t, const Int_t *) override
Creates the fftw-plan.

TClassIsA () const override

Bool_t IsInplace () const override

void SetPoint (const Int_t *ipoint, Double_t re, Double_t im=0) override
For multidimensional transforms. Set the point #ipoint

void SetPoint (Int_t ipoint, Double_t re, Double_t im=0) override
Set the point #ipoint

void SetPointComplex (Int_t ipoint, TComplex &c) override
Sets the point #ipoint (only the real part of the argument is taken)

void SetPoints (const Double_t *data) override
Set all input points.

void SetPointsComplex (const Double_t *re, const Double_t *im) override
Set all points. Only the real array is used.

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

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

void Transform () override
Computes the transform, specified in Init() function.

Public Member Functions inherited from TVirtualFFT
TVirtualFFT ()

virtual ~TVirtualFFT ()
destructor

TClassIsA () const override

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

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

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

TObject (const TObject &object)
TObject copy ctor.

virtual ~TObject ()
TObject destructor.

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

Append graphics object to current pad.

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

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.

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

virtual void Clear (Option_t *="")

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

virtual Option_tGetOption () const

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

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

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

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

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.

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

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

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

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

void InvertBit (UInt_t f)

Bool_t IsDestructed () const
IsDestructed.

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

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

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.

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).

virtual Bool_t Notify ()
This method must be overridden to handle object notification (the base implementation is no-op).

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

void operator delete (void *ptr)
Operator delete.

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

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.

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

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

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

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

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

void ResetBit (UInt_t f)

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

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

void SetBit (UInt_t f)

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

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

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

void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

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

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.

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

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

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

## Static Public Member Functions

static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

Static Public Member Functions inherited from TVirtualFFT
static TClassClass ()

static const char * Class_Name ()

static constexpr Version_t Class_Version ()

static const char * DeclFileName ()

static TVirtualFFTFFT (Int_t ndim, Int_t *n, Option_t *option)
Returns a pointer to the FFT of requested size and type.

static TVirtualFFTGetCurrentTransform ()
static: return current fgFFT

static const char * GetDefaultFFT ()
static: return the name of the default fft

static void SetDefaultFFT (const char *name="")
static: set name of default fft

static void SetTransform (TVirtualFFT *fft)
static: set the current transfrom to parameter

static TVirtualFFTSineCosine (Int_t ndim, Int_t *n, Int_t *r2rkind, Option_t *option)
Returns a pointer to a sine or cosine transform of requested size and kind.

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.

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

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

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

## Protected Member Functions

UInt_t MapFlag (Option_t *flag)
allowed options: "ES" "M" "P" "EX"

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).

void MakeZombie ()

## Protected Attributes

TString fFlags

void * fIn

Int_tfN

Int_t fNdim

void * fOut

void * fPlan

Int_t fTotalSize

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 )) }

Static Protected Attributes inherited from TVirtualFFT
static TString fgDefault = ""

static TVirtualFFTfgFFT = nullptr

#include <TFFTRealComplex.h>

Inheritance diagram for TFFTRealComplex:
[legend]

## ◆ TFFTRealComplex() [1/3]

 TFFTRealComplex::TFFTRealComplex ( )

default

Definition at line 55 of file TFFTRealComplex.cxx.

## ◆ TFFTRealComplex() [2/3]

 TFFTRealComplex::TFFTRealComplex ( Int_t n, Bool_t inPlace )

For 1d transforms Allocates memory for the input array, and, if inPlace = kFALSE, for the output array.

Definition at line 69 of file TFFTRealComplex.cxx.

## ◆ TFFTRealComplex() [3/3]

 TFFTRealComplex::TFFTRealComplex ( Int_t ndim, Int_t * n, Bool_t inPlace )

For ndim-dimensional transforms Second argument contains sizes of the transform in each dimension.

Definition at line 90 of file TFFTRealComplex.cxx.

## ◆ ~TFFTRealComplex()

 TFFTRealComplex::~TFFTRealComplex ( )
override

Destroys the data arrays and the plan.

However, some plan information stays around until the root session is over, and is reused if other plans of the same size are created

Definition at line 119 of file TFFTRealComplex.cxx.

## ◆ Class()

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

## ◆ Class_Name()

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

## ◆ Class_Version()

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

Definition at line 64 of file TFFTRealComplex.h.

## ◆ DeclFileName()

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

Definition at line 64 of file TFFTRealComplex.h.

## ◆ GetN()

 Int_t * TFFTRealComplex::GetN ( ) const
inlineoverridevirtual

Implements TVirtualFFT.

Definition at line 41 of file TFFTRealComplex.h.

## ◆ GetNdim()

 Int_t TFFTRealComplex::GetNdim ( ) const
inlineoverridevirtual

Implements TVirtualFFT.

Definition at line 42 of file TFFTRealComplex.h.

## ◆ GetPointComplex() [1/2]

 void TFFTRealComplex::GetPointComplex ( const Int_t * ipoint, Double_t & re, Double_t & im, Bool_t fromInput = kFALSE ) const
overridevirtual

For multidimensional transforms.

Returns the point #ipoint. In case of transforms of more than 2 dimensions, only points from the first (roughly)half are returned, the rest being Hermitian symmetric

Implements TVirtualFFT.

Definition at line 290 of file TFFTRealComplex.cxx.

## ◆ GetPointComplex() [2/2]

 void TFFTRealComplex::GetPointComplex ( Int_t ipoint, Double_t & re, Double_t & im, Bool_t fromInput = kFALSE ) const
overridevirtual

Returns the point #ipoint.

For 1d, if ipoint > fN/2+1 (the point is in the Hermitian symmetric part), it is still returned. For >1d, only the first (roughly)half of points can be returned For 2d, see function GetPointComplex(Int_t *ipoint,...)

Implements TVirtualFFT.

Definition at line 245 of file TFFTRealComplex.cxx.

## ◆ GetPointReal() [1/2]

 Double_t TFFTRealComplex::GetPointReal ( const Int_t * ipoint, Bool_t fromInput = kFALSE ) const
overridevirtual

Returns the real part of the point #ipoint from the output or the point #ipoint from the input.

Implements TVirtualFFT.

Definition at line 224 of file TFFTRealComplex.cxx.

## ◆ GetPointReal() [2/2]

 Double_t TFFTRealComplex::GetPointReal ( Int_t ipoint, Bool_t fromInput = kFALSE ) const
overridevirtual

Returns the real part of the point #ipoint from the output or the point #ipoint from the input.

Implements TVirtualFFT.

Definition at line 210 of file TFFTRealComplex.cxx.

## ◆ GetPoints()

 void TFFTRealComplex::GetPoints ( Double_t * data, Bool_t fromInput = kFALSE ) const
overridevirtual

Fills the array data with the computed transform.

Only (roughly) a half of the transform is copied (exactly the output of FFTW), the rest being Hermitian symmetric with the first half

Implements TVirtualFFT.

Definition at line 186 of file TFFTRealComplex.cxx.

## ◆ GetPointsComplex() [1/2]

 void TFFTRealComplex::GetPointsComplex ( Double_t * data, Bool_t fromInput = kFALSE ) const
overridevirtual

Fills the argument arrays with the real and imaginary parts of the computed transform.

Only (roughly) a half of the transform is copied, the rest being Hermitian symmetric with the first half

Implements TVirtualFFT.

Definition at line 411 of file TFFTRealComplex.cxx.

## ◆ GetPointsComplex() [2/2]

 void TFFTRealComplex::GetPointsComplex ( Double_t * re, Double_t * im, Bool_t fromInput = kFALSE ) const
overridevirtual

Fills the argument arrays with the real and imaginary parts of the computed transform.

Only (roughly) a half of the transform is copied, the rest being Hermitian symmetric with the first half

Implements TVirtualFFT.

Definition at line 382 of file TFFTRealComplex.cxx.

## ◆ GetPointsReal()

 Double_t * TFFTRealComplex::GetPointsReal ( Bool_t fromInput = kFALSE ) const
overridevirtual

Returns the input array// One of the interface classes to the FFTW package, can be used directly or via the TVirtualFFT class.

Only the basic interface of FFTW is implemented.

Implements TVirtualFFT.

Definition at line 368 of file TFFTRealComplex.cxx.

## ◆ GetSign()

 Int_t TFFTRealComplex::GetSign ( ) const
inlineoverridevirtual

Implements TVirtualFFT.

Definition at line 44 of file TFFTRealComplex.h.

## ◆ GetSize()

 virtual Int_t TFFTRealComplex::GetSize ( ) const
inlinevirtual

Definition at line 40 of file TFFTRealComplex.h.

## ◆ GetTransformFlag()

 Option_t * TFFTRealComplex::GetTransformFlag ( ) const
inlineoverridevirtual

Implements TVirtualFFT.

Definition at line 45 of file TFFTRealComplex.h.

## ◆ GetType()

 Option_t * TFFTRealComplex::GetType ( ) const
inlineoverridevirtual

Implements TVirtualFFT.

Definition at line 43 of file TFFTRealComplex.h.

## ◆ Init()

 void TFFTRealComplex::Init ( Option_t * flags, Int_t , const Int_t * )
overridevirtual

Creates the fftw-plan.

NOTE: input and output arrays are overwritten during initialisation, so don't set any points, before running this function!!!!!

Arguments sign and kind are dummy and not need to be specified Possible flag_options:

• "ES" (from "estimate") - no time in preparing the transform, but probably sub-optimal performance
• "M" (from "measure") - some time spend in finding the optimal way to do the transform
• "P" (from "patient") - more time spend in finding the optimal way to do the transform
• "EX" (from "exhaustive") - the most optimal way is found

This option should be chosen depending on how many transforms of the same size and type are going to be done. Planning is only done once, for the first transform of this size and type.

Implements TVirtualFFT.

Definition at line 152 of file TFFTRealComplex.cxx.

## ◆ IsA()

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

Reimplemented from TObject.

Definition at line 64 of file TFFTRealComplex.h.

## ◆ IsInplace()

 Bool_t TFFTRealComplex::IsInplace ( ) const
inlineoverridevirtual

Implements TVirtualFFT.

Definition at line 46 of file TFFTRealComplex.h.

## ◆ MapFlag()

 UInt_t TFFTRealComplex::MapFlag ( Option_t * flag )
protected

allowed options: "ES" "M" "P" "EX"

Definition at line 489 of file TFFTRealComplex.cxx.

## ◆ SetPoint() [1/2]

 void TFFTRealComplex::SetPoint ( const Int_t * ipoint, Double_t re, Double_t im = 0 )
overridevirtual

For multidimensional transforms. Set the point #ipoint

Implements TVirtualFFT.

Definition at line 447 of file TFFTRealComplex.cxx.

## ◆ SetPoint() [2/2]

 void TFFTRealComplex::SetPoint ( Int_t ipoint, Double_t re, Double_t im = 0 )
overridevirtual

Set the point #ipoint

Implements TVirtualFFT.

Definition at line 439 of file TFFTRealComplex.cxx.

## ◆ SetPointComplex()

 void TFFTRealComplex::SetPointComplex ( Int_t ipoint, TComplex & c )
overridevirtual

Sets the point #ipoint (only the real part of the argument is taken)

Implements TVirtualFFT.

Definition at line 468 of file TFFTRealComplex.cxx.

## ◆ SetPoints()

 void TFFTRealComplex::SetPoints ( const Double_t * data )
overridevirtual

Set all input points.

Implements TVirtualFFT.

Definition at line 458 of file TFFTRealComplex.cxx.

## ◆ SetPointsComplex()

 void TFFTRealComplex::SetPointsComplex ( const Double_t * re, const Double_t * im )
overridevirtual

Set all points. Only the real array is used.

Implements TVirtualFFT.

Definition at line 476 of file TFFTRealComplex.cxx.

## ◆ Streamer()

 void TFFTRealComplex::Streamer ( TBuffer & R__b )
overridevirtual

Stream an object of class TObject.

Reimplemented from TObject.

## ◆ StreamerNVirtual()

 void TFFTRealComplex::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )
inline

Definition at line 64 of file TFFTRealComplex.h.

## ◆ Transform()

 void TFFTRealComplex::Transform ( )
overridevirtual

Computes the transform, specified in Init() function.

Implements TVirtualFFT.

Definition at line 169 of file TFFTRealComplex.cxx.

## ◆ fFlags

 TString TFFTRealComplex::fFlags
protected

Definition at line 28 of file TFFTRealComplex.h.

## ◆ fIn

 void* TFFTRealComplex::fIn
protected

Definition at line 22 of file TFFTRealComplex.h.

## ◆ fN

 Int_t* TFFTRealComplex::fN
protected

Definition at line 27 of file TFFTRealComplex.h.

## ◆ fNdim

 Int_t TFFTRealComplex::fNdim
protected

Definition at line 25 of file TFFTRealComplex.h.

## ◆ fOut

 void* TFFTRealComplex::fOut
protected

Definition at line 23 of file TFFTRealComplex.h.

## ◆ fPlan

 void* TFFTRealComplex::fPlan
protected

Definition at line 24 of file TFFTRealComplex.h.

## ◆ fTotalSize

 Int_t TFFTRealComplex::fTotalSize
protected

Definition at line 26 of file TFFTRealComplex.h.

Libraries for TFFTRealComplex:

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