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Reference Guide
THnChain Class Reference

A class to chain together multiple histograms.

This class allows to chain together any THnBase-derived (THn or THnSparse) histograms from multiple files. Operations on the axes and projections are supported. The intent is to allow convenient merging merging of projections of high-dimensional histograms.

// `file1.root` and `file2.root` contain a `THnSparse` named `hsparse`.
THnChain hs("hsparse");
hs.AddFile("file1.root");
hs.AddFile("file2.root");
// Project out axis 0, integrate over other axes.
TH1* h0 = hs.Projection(0);
// Project out axis 0, integrate over other axes in their active ranges.
hs.GetAxis(1)->SetRangeUser(0, 0.1); // select a subrange
TH1* h0 = hs.Projection(0);
The TH1 histogram class.
Definition: TH1.h:56
A class to chain together multiple histograms.
Definition: THnChain.h:50

Definition at line 49 of file THnChain.h.

Public Member Functions

 THnChain (const char *name)
 Default constructor. More...
 
void AddFile (const char *fileName)
 Add a new file to this chain. More...
 
TAxisGetAxis (Int_t i) const
 Get an axis from the histogram. More...
 
TH3Projection (Int_t xDim, Int_t yDim, Int_t zDim, Option_t *option="") const
 See THnBase::Projection for the intended behavior. More...
 
TH1Projection (Int_t xDim, Option_t *option="") const
 See THnBase::Projection for the intended behavior. More...
 
TH2Projection (Int_t yDim, Int_t xDim, Option_t *option="") const
 See THnBase::Projection for the intended behavior. More...
 
THnBaseProjectionND (Int_t ndim, const Int_t *dim, Option_t *option="") const
 See THnBase::Projection for the intended behavior. More...
 
- 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...
 
virtual void AppendPad (Option_t *option="")
 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 for instance with: gROOT->SetSelectedPad(gPad). 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=0)
 Execute method on this object with the given parameter string, e.g. More...
 
virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
 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 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...
 
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. 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 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=0, Int_t option=0, Int_t bufsize=0)
 Write this object to the current directory. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write this object to the current directory. More...
 

Private Member Functions

TObjectProjectionAny (Int_t ndim, const Int_t *dim, Option_t *option="") const
 Projects all histograms in the chain. More...
 
THnBaseReadHistogram (const char *fileName) const
 Retrieve a histogram from a file. More...
 
void SetupAxes (THnBase &hs) const
 Copy the properties of all axes to a histogram. More...
 

Static Private Member Functions

static bool CheckConsistency (const THnBase &h, const std::vector< TAxis * > &axes)
 Ensure a histogram has axes similar to the ones we expect. More...
 

Private Attributes

std::vector< TAxis * > fAxes
 the list of histogram axes More...
 
std::vector< std::string > fFiles
 a list of files to extract the histogram from More...
 
std::string fName
 name of the histogram More...
 

Additional Inherited Members

- Public Types inherited from TObject
enum  {
  kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 ,
  kBitMask = 0x00ffffff
}
 
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 TObject
static Long_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...
 
- 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 <THnChain.h>

Inheritance diagram for THnChain:
[legend]

Constructor & Destructor Documentation

◆ THnChain()

THnChain::THnChain ( const char *  name)
inlineexplicit

Default constructor.

Parameters
namename of the histogram to work on

Definition at line 55 of file THnChain.h.

Member Function Documentation

◆ AddFile()

void THnChain::AddFile ( const char *  fileName)

Add a new file to this chain.

Parameters
fileNamepath of the file to add

Definition at line 24 of file THnChain.cxx.

◆ CheckConsistency()

bool THnChain::CheckConsistency ( const THnBase h,
const std::vector< TAxis * > &  axes 
)
staticprivate

Ensure a histogram has axes similar to the ones we expect.

Parameters
hhistogram to verify
axesexpected set of axes

Definition at line 145 of file THnChain.cxx.

◆ GetAxis()

TAxis * THnChain::GetAxis ( Int_t  i) const

Get an axis from the histogram.

Parameters
iindex of the axis to retrieve

This function requires that a file containing the histogram was already added with AddFile.

Properties set on the axis returned by GetAxis are propagated to all histograms in the chain, so it can e.g. be used to set ranges for projections.

Definition at line 46 of file THnChain.cxx.

◆ Projection() [1/3]

TH3 * THnChain::Projection ( Int_t  xDim,
Int_t  yDim,
Int_t  zDim,
Option_t option = "" 
) const

See THnBase::Projection for the intended behavior.

Definition at line 209 of file THnChain.cxx.

◆ Projection() [2/3]

TH1 * THnChain::Projection ( Int_t  xDim,
Option_t option = "" 
) const

See THnBase::Projection for the intended behavior.

Definition at line 195 of file THnChain.cxx.

◆ Projection() [3/3]

TH2 * THnChain::Projection ( Int_t  yDim,
Int_t  xDim,
Option_t option = "" 
) const

See THnBase::Projection for the intended behavior.

Definition at line 202 of file THnChain.cxx.

◆ ProjectionAny()

TObject * THnChain::ProjectionAny ( Int_t  ndim,
const Int_t dim,
Option_t option = "" 
) const
private

Projects all histograms in the chain.

See THnBase::Projection for parameters and their semantics.

Definition at line 55 of file THnChain.cxx.

◆ ProjectionND()

THnBase * THnChain::ProjectionND ( Int_t  ndim,
const Int_t dim,
Option_t option = "" 
) const

See THnBase::Projection for the intended behavior.

Definition at line 216 of file THnChain.cxx.

◆ ReadHistogram()

THnBase * THnChain::ReadHistogram ( const char *  fileName) const
private

Retrieve a histogram from a file.

Parameters
fileNamepath of the file to read.

Definition at line 118 of file THnChain.cxx.

◆ SetupAxes()

void THnChain::SetupAxes ( THnBase hs) const
private

Copy the properties of all axes to a histogram.

Parameters
hshistogram whose axes should be updated

Definition at line 135 of file THnChain.cxx.

Member Data Documentation

◆ fAxes

std::vector<TAxis*> THnChain::fAxes
private

the list of histogram axes

Definition at line 90 of file THnChain.h.

◆ fFiles

std::vector<std::string> THnChain::fFiles
private

a list of files to extract the histogram from

Definition at line 89 of file THnChain.h.

◆ fName

std::string THnChain::fName
private

name of the histogram

Definition at line 87 of file THnChain.h.

Libraries for THnChain:
[legend]

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