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TFFTComplex 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 complex input/output discrete Fourier transforms (DFT) in one or more dimensions. For the detailed information on the computed transforms please refer to the FFTW manual, chapter "What FFTW really computes".

How to use it:

1. Create an instance of TFFTComplex - 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
3. Set the data (via SetPoints(), SetPoint() or SetPointComplex() functions)
4. Run the Transform() function
5. Get the output (via GetPoints(), GetPoint() or GetPointComplex() functions)
6. Repeat steps 3)-5) as needed

For a transform of the same size, but with different flags or sign, 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 TFFTComplex.h.

## Public Member Functions

TFFTComplex ()
default

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

TFFTComplex (Int_t ndim, Int_t *n, Bool_t inPlace=kFALSE)
For multidim.

virtual ~TFFTComplex ()
Destroys the data arrays and the plan.

virtual Int_tGetN () const

virtual Int_t GetNdim () const

virtual void GetPointComplex (const Int_t *ipoint, Double_t &re, Double_t &im, Bool_t fromInput=kFALSE) const
For multidimensional transforms. Returns real and imaginary parts of the point #ipoint.

virtual void GetPointComplex (Int_t ipoint, Double_t &re, Double_t &im, Bool_t fromInput=kFALSE) const
returns real and imaginary parts of the point #ipoint

virtual Double_t GetPointReal (const Int_t *, Bool_t) const

virtual Double_t GetPointReal (Int_t, Bool_t) const

virtual void GetPoints (Double_t *data, Bool_t fromInput=kFALSE) const
Copies the output(or input) into the argument array.

virtual void GetPointsComplex (Double_t *data, Bool_t fromInput=kFALSE) const
Copies the output(input) into the argument array.

virtual void GetPointsComplex (Double_t *re, Double_t *im, Bool_t fromInput=kFALSE) const
Copies real and imaginary parts of the output (input) into the argument arrays.

virtual Double_tGetPointsReal (Bool_t) const

virtual Int_t GetSign () const

virtual Int_t GetSize () const

virtual Option_tGetTransformFlag () const

virtual Option_tGetType () const

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

virtual Bool_t IsInplace () const

virtual void SetPoint (const Int_t *ipoint, Double_t re, Double_t im=0)
For multidim. transforms. Sets real and imaginary parts of point # ipoint.

virtual void SetPoint (Int_t ipoint, Double_t re, Double_t im=0)
sets real and imaginary parts of point # ipoint

virtual void SetPointComplex (Int_t ipoint, TComplex &c)

virtual void SetPoints (const Double_t *data)
set all points.

virtual void SetPointsComplex (const Double_t *re, const Double_t *im)
set all points. the values are copied

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

Public Member Functions inherited from TVirtualFFT
TVirtualFFT ()

virtual ~TVirtualFFT ()
destructor

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 for instance with: gROOT->SetSelectedPad(gPad).

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=0)
Execute method on this object with the given parameter string, e.g.

virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
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)

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.

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 [].

voidoperator new (size_t sz)

voidoperator new (size_t sz, void *vp)

voidoperator new[] (size_t sz)

voidoperator 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.

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=0, Int_t option=0, Int_t bufsize=0)
Write this object to the current directory.

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

## Protected Member Functions

UInt_t MapFlag (Option_t *flag)
allowed options:

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

voidfIn

Int_tfN

Int_t fNdim

voidfOut

voidfPlan

Int_t fSign

Int_t fTotalSize

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

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

enum  EDeprecatedStatusBits { kObjInCanvas = BIT(3) }

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

Static Public Member Functions inherited from TVirtualFFT
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 Long_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 Types inherited from TObject
enum  { kOnlyPrepStep = BIT(3) }

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

static TVirtualFFTfgFFT = 0

#include <TFFTComplex.h>

Inheritance diagram for TFFTComplex:
[legend]

## ◆ TFFTComplex() [1/3]

 TFFTComplex::TFFTComplex ( )

default

Definition at line 52 of file TFFTComplex.cxx.

## ◆ TFFTComplex() [2/3]

 TFFTComplex::TFFTComplex ( 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 67 of file TFFTComplex.cxx.

## ◆ TFFTComplex() [3/3]

 TFFTComplex::TFFTComplex ( Int_t ndim, Int_t * n, Bool_t inPlace = kFALSE )

For multidim.

transforms Allocates memory for the input array, and, if inPlace = kFALSE, for the output array

Definition at line 86 of file TFFTComplex.cxx.

## ◆ ~TFFTComplex()

 TFFTComplex::~TFFTComplex ( )
virtual

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 109 of file TFFTComplex.cxx.

## ◆ GetN()

 virtual Int_t * TFFTComplex::GetN ( ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 41 of file TFFTComplex.h.

## ◆ GetNdim()

 virtual Int_t TFFTComplex::GetNdim ( ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 42 of file TFFTComplex.h.

## ◆ GetPointComplex() [1/2]

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

For multidimensional transforms. Returns real and imaginary parts of the point #ipoint.

Implements TVirtualFFT.

Definition at line 203 of file TFFTComplex.cxx.

## ◆ GetPointComplex() [2/2]

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

returns real and imaginary parts of the point #ipoint

Implements TVirtualFFT.

Definition at line 189 of file TFFTComplex.cxx.

## ◆ GetPointReal() [1/2]

 virtual Double_t TFFTComplex::GetPointReal ( const Int_t * , Bool_t ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 51 of file TFFTComplex.h.

## ◆ GetPointReal() [2/2]

 virtual Double_t TFFTComplex::GetPointReal ( Int_t , Bool_t ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 50 of file TFFTComplex.h.

## ◆ GetPoints()

 void TFFTComplex::GetPoints ( Double_t * data, Bool_t fromInput = kFALSE ) const
virtual

Copies the output(or input) into the argument array.

Implements TVirtualFFT.

Definition at line 171 of file TFFTComplex.cxx.

## ◆ GetPointsComplex() [1/2]

 void TFFTComplex::GetPointsComplex ( Double_t * data, Bool_t fromInput = kFALSE ) const
virtual

Copies the output(input) into the argument array.

Implements TVirtualFFT.

Definition at line 239 of file TFFTComplex.cxx.

## ◆ GetPointsComplex() [2/2]

 void TFFTComplex::GetPointsComplex ( Double_t * re, Double_t * im, Bool_t fromInput = kFALSE ) const
virtual

Copies real and imaginary parts of the output (input) into the argument arrays.

Implements TVirtualFFT.

Definition at line 221 of file TFFTComplex.cxx.

## ◆ GetPointsReal()

 virtual Double_t * TFFTComplex::GetPointsReal ( Bool_t ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 54 of file TFFTComplex.h.

## ◆ GetSign()

 virtual Int_t TFFTComplex::GetSign ( ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 45 of file TFFTComplex.h.

## ◆ GetSize()

 virtual Int_t TFFTComplex::GetSize ( ) const
inlinevirtual

Definition at line 43 of file TFFTComplex.h.

## ◆ GetTransformFlag()

 virtual Option_t * TFFTComplex::GetTransformFlag ( ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 46 of file TFFTComplex.h.

## ◆ GetType()

 virtual Option_t * TFFTComplex::GetType ( ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 44 of file TFFTComplex.h.

## ◆ Init()

 void TFFTComplex::Init ( Option_t * flags, Int_t sign, const Int_t * )
virtual

Creates the fftw-plan.

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

2nd parameter: +1

Argument kind is dummy and doesn't 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 140 of file TFFTComplex.cxx.

## ◆ IsInplace()

 virtual Bool_t TFFTComplex::IsInplace ( ) const
inlinevirtual

Implements TVirtualFFT.

Definition at line 47 of file TFFTComplex.h.

## ◆ MapFlag()

 UInt_t TFFTComplex::MapFlag ( Option_t * flag )
protected

allowed options:

• "ES" - FFTW_ESTIMATE
• "M" - FFTW_MEASURE
• "P" - FFTW_PATIENT
• "EX" - FFTW_EXHAUSTIVE

Definition at line 318 of file TFFTComplex.cxx.

## ◆ SetPoint() [1/2]

 void TFFTComplex::SetPoint ( const Int_t * ipoint, Double_t re, Double_t im = 0 )
virtual

For multidim. transforms. Sets real and imaginary parts of point # ipoint.

Implements TVirtualFFT.

Definition at line 266 of file TFFTComplex.cxx.

## ◆ SetPoint() [2/2]

 void TFFTComplex::SetPoint ( Int_t ipoint, Double_t re, Double_t im = 0 )
virtual

sets real and imaginary parts of point # ipoint

Implements TVirtualFFT.

Definition at line 257 of file TFFTComplex.cxx.

## ◆ SetPointComplex()

 void TFFTComplex::SetPointComplex ( Int_t ipoint, TComplex & c )
virtual

Implements TVirtualFFT.

Definition at line 278 of file TFFTComplex.cxx.

## ◆ SetPoints()

 void TFFTComplex::SetPoints ( const Double_t * data )
virtual

set all points.

the values are copied. points should be ordered as follows: [re_0, im_0, re_1, im_1, ..., re_n, im_n)

Implements TVirtualFFT.

Definition at line 288 of file TFFTComplex.cxx.

## ◆ SetPointsComplex()

 void TFFTComplex::SetPointsComplex ( const Double_t * re, const Double_t * im )
virtual

set all points. the values are copied

Implements TVirtualFFT.

Definition at line 299 of file TFFTComplex.cxx.

## ◆ Transform()

 void TFFTComplex::Transform ( )
virtual

Computes the transform, specified in Init() function.

Implements TVirtualFFT.

Definition at line 158 of file TFFTComplex.cxx.

## ◆ fFlags

 TString TFFTComplex::fFlags
protected

Definition at line 29 of file TFFTComplex.h.

## ◆ fIn

 void* TFFTComplex::fIn
protected

Definition at line 22 of file TFFTComplex.h.

## ◆ fN

 Int_t* TFFTComplex::fN
protected

Definition at line 27 of file TFFTComplex.h.

## ◆ fNdim

 Int_t TFFTComplex::fNdim
protected

Definition at line 25 of file TFFTComplex.h.

## ◆ fOut

 void* TFFTComplex::fOut
protected

Definition at line 23 of file TFFTComplex.h.

## ◆ fPlan

 void* TFFTComplex::fPlan
protected

Definition at line 24 of file TFFTComplex.h.

## ◆ fSign

 Int_t TFFTComplex::fSign
protected

Definition at line 28 of file TFFTComplex.h.

## ◆ fTotalSize

 Int_t TFFTComplex::fTotalSize
protected

Definition at line 26 of file TFFTComplex.h.

Libraries for TFFTComplex:

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