RooFormula internally uses ROOT's TFormula to compute user-defined expressions of RooAbsArgs.

The string expression can be any valid TFormula expression referring to the listed servers either by name or by their ordinal list position. These three are forms equivalent:

RooFormula("formula", "x*y",       RooArgList(x,y))  or
RooFormula("formula", "@0*@1",     RooArgList(x,y))
RooFormula("formula", "x[0]*x[1]", RooArgList(x,y))

Note that x[i] is an expression reserved for TFormula. If a variable with the name x is given, the RooFormula interprets x as a variable name, but x[i] as an index in the list of variables.

Category expressions

State information of RooAbsCategories can be accessed using the '::' operator, i.e.*, tagCat::Kaon will resolve to the numerical value of the Kaon state of the RooAbsCategory object named tagCat.

A formula to switch between lepton categories could look like this:

RooFormula("formulaWithCat",
  "x * (leptonMulti == leptonMulti::one) + y * (leptonMulti == leptonMulti::two)",
  RooArgList(x, y, leptonMulti));

Debugging a formula that won't compile

When the formula is preprocessed, RooFit can print information in the debug stream. These can be retrieved by activating the RooFit::MsgLevel RooFit::DEBUG and the RooFit::MsgTopic RooFit::InputArguments. Check the tutorial rf506_msgservice.C for details.

Definition at line 34 of file RooFormula.h.

Public Member Functions
	RooFormula ()
	Default constructor coverity[UNINIT_CTOR].

	RooFormula (const char name, const char formula, const RooArgList &varList, bool checkVariables=true)
	Construct a new formula.

	RooFormula (const RooFormula &other, const char *name=0)
	Copy constructor.

RooArgSet	actualDependents () const
	Return list of arguments which are used in the formula.

Bool_t	changeDependents (const RooAbsCollection &newDeps, Bool_t mustReplaceAll, Bool_t nameChange)
	Change used variables to those with the same name in given list.

virtual TObject *	Clone (const char *newName=nullptr) const
	Make a clone of an object using the Streamer facility.

void	dump () const
	DEBUG: Dump state information.

Double_t	eval (const RooArgSet *nset=0) const
	Evalute all parameters/observables, and then evaluate formula.

RooSpan< double >	evaluateSpan (const RooAbsReal dataOwner, RooBatchCompute::RunContext &inputData, const RooArgSet nset=nullptr) const

std::string	formulaString () const

RooAbsArg *	getParameter (const char *name) const
	Return pointer to the parameter with given name.

RooAbsArg *	getParameter (Int_t index) const
	Return pointer to parameter at given index.

Bool_t	ok () const

virtual void	Print (Option_t *options=0) const
	Print TNamed name and title.

virtual void	printArgs (std::ostream &os) const
	Print arguments of formula, i.e. dependents that are actually used.

virtual void	printClassName (std::ostream &os) const
	Print class name of formula.

void	printMultiline (std::ostream &os, Int_t contents, Bool_t verbose=kFALSE, TString indent="") const
	Printing interface.

virtual void	printName (std::ostream &os) const
	Print name of formula.

virtual void	printTitle (std::ostream &os) const
	Print title of formula.

virtual void	printValue (std::ostream &os) const
	Print value of formula.

Bool_t	reCompile (const char *newFormula)
	Recompile formula with new expression.

Public Member Functions inherited from TNamed
	TNamed ()

	TNamed (const char name, const char title)

	TNamed (const TNamed &named)
	TNamed copy ctor.

	TNamed (const TString &name, const TString &title)

virtual	~TNamed ()
	TNamed destructor.

virtual void	Clear (Option_t *option="")
	Set name and title to empty strings ("").

virtual Int_t	Compare (const TObject *obj) const
	Compare two TNamed objects.

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

virtual void	FillBuffer (char *&buffer)
	Encode TNamed into output buffer.

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

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

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

virtual Bool_t	IsSortable () const

virtual void	ls (Option_t *option="") const
	List TNamed name and title.

TNamed &	operator= (const TNamed &rhs)
	TNamed assignment operator.

virtual void	SetName (const char *name)
	Set the name of the TNamed.

virtual void	SetNameTitle (const char name, const char title)
	Set all the TNamed parameters (name and title).

virtual void	SetTitle (const char *title="")
	Set the title of the TNamed.

virtual Int_t	Sizeof () const
	Return size of the TNamed part of the TObject.

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.

virtual void	AppendPad (Option_t *option="")
	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	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 TObject *	DrawClone (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 TObject *	FindObject (const char *name) const
	Must be redefined in derived classes.

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

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

virtual const char *	GetIconName () const
	Returns mime type 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_t *	GetOption () const

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.

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

R__ALWAYS_INLINE Bool_t	IsZombie () const

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 [].

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)

TObject &	operator= (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 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.

Public Member Functions inherited from RooPrintable
	RooPrintable ()

virtual	~RooPrintable ()

virtual Int_t	defaultPrintContents (Option_t *opt) const
	Default choice of contents to be printed (name and value)

virtual StyleOption	defaultPrintStyle (Option_t *opt) const

virtual void	printAddress (std::ostream &os) const
	Print class name of object.

virtual void	printExtras (std::ostream &os) const
	Interface to print extras of object.

virtual void	printStream (std::ostream &os, Int_t contents, StyleOption style, TString indent="") const
	Print description of object on ostream, printing contents set by contents integer, which is interpreted as an OR of 'enum ContentsOptions' values and in the style given by 'enum StyleOption'.

virtual void	printTree (std::ostream &os, TString indent="") const
	Interface for tree structure printing of object.

Private Member Functions
void	installFormulaOrThrow (const std::string &formulaa)
	Check that the formula compiles, and also fulfills the assumptions.

RooFormula &	operator= (const RooFormula &other)

std::string	processFormula (std::string origFormula) const
	Process given formula by replacing all ordinal and name references by `x[i]`, where `i` matches the position of the argument in `_origList`.

std::string	reconstructFormula (std::string internalRepr) const
	From the internal representation, construct a formula by replacing all index place holders with the names of the variables that are being used to evaluate it.

RooArgList	usedVariables () const
	Analyse internal formula to find out which variables are actually in use.

Private Attributes
std::vector< bool >	_isCategory
	Original list of dependents.

RooArgList	_origList

std::unique_ptr< TFormula >	_tFormula
	Whether an element of the _origList is a category.

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) }

Public Types inherited from RooPrintable
enum	ContentsOption { kName =1 , kClassName =2 , kValue =4 , kArgs =8 , kExtras =16 , kAddress =32 , kTitle =64 , kCollectionHeader =128 }

enum	StyleOption { kInline =1 , kSingleLine =2 , kStandard =3 , kVerbose =4 , kTreeStructure =5 }

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.

Static Public Member Functions inherited from RooPrintable
static std::ostream &	defaultPrintStream (std::ostream *os=0)
	Return a reference to the current default stream to use in Print().

static void	nameFieldLength (Int_t newLen)
	Set length of field reserved from printing name of RooAbsArgs in multi-line collection printing to given amount.

Protected Types inherited from TObject
enum	{ kOnlyPrepStep = BIT(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).

void	MakeZombie ()

Protected Attributes inherited from TNamed
TString	fName

TString	fTitle

Static Protected Attributes inherited from RooPrintable
static Int_t	_nameLength

#include <RooFormula.h>

Inheritance diagram for RooFormula:

[legend]

Constructor & Destructor Documentation

◆ RooFormula() [1/3]

RooFormula::RooFormula ( )

Default constructor coverity[UNINIT_CTOR].

Definition at line 98 of file RooFormula.cxx.

◆ RooFormula() [2/3]

RooFormula::RooFormula	(	const char *	name,
		const char *	formula,
		const RooArgList &	varList,
		bool	checkVariables = `true`
	)

Construct a new formula.

Parameters

[in]	name	Name of the formula.
[in]	formula	Formula to be evaluated. Parameters/observables are identified by name or ordinal position in `varList`.
[in]	varList	List of variables to be passed to the formula.
[in]	checkVariables	Check that the variables being passed in the `varList` are used in the formula expression.

Definition at line 111 of file RooFormula.cxx.

◆ RooFormula() [3/3]

RooFormula::RooFormula	(	const RooFormula &	other,
		const char *	name = `0`
	)

Copy constructor.

Definition at line 132 of file RooFormula.cxx.

Member Function Documentation

◆ actualDependents()

RooArgSet RooFormula::actualDependents ( ) const

inline

Return list of arguments which are used in the formula.

Definition at line 44 of file RooFormula.h.

◆ changeDependents()

Bool_t RooFormula::changeDependents	(	const RooAbsCollection &	newDeps,
		Bool_t	mustReplaceAll,
		Bool_t	nameChange
	)

Change used variables to those with the same name in given list.

Parameters

[in]	newDeps	New dependents to replace the old ones.
[in]	mustReplaceAll	Will yield an error if one dependent does not have a replacement.
[in]	nameChange	Passed down to RooAbsArg::findNewServer(const RooAbsCollection&, Bool_t) const.

Definition at line 306 of file RooFormula.cxx.

◆ Clone()

virtual TObject * RooFormula::Clone ( const char * newname = nullptr ) const

inlinevirtual

Make a clone of an object using the Streamer facility.

If newname is specified, this will be the name of the new object.

Reimplemented from TNamed.

Definition at line 40 of file RooFormula.h.

◆ dump()

void RooFormula::dump ( ) const

DEBUG: Dump state information.

Definition at line 295 of file RooFormula.cxx.

◆ eval()

Double_t RooFormula::eval ( const RooArgSet * nset = 0 ) const

Evalute all parameters/observables, and then evaluate formula.

Evaluate the internal TFormula.

First, all variables serving this instance are evaluated given the normalisation set, and then the formula is evaluated.

Parameters

[in] nset Normalisation set passed to evaluation of arguments serving values.

Returns: The result of the evaluation.

Definition at line 342 of file RooFormula.cxx.

◆ evaluateSpan()

RooSpan< double > RooFormula::evaluateSpan	(	const RooAbsReal *	dataOwner,
		RooBatchCompute::RunContext &	inputData,
		const RooArgSet *	nset = `nullptr`
	)		const

Definition at line 368 of file RooFormula.cxx.

◆ formulaString()

std::string RooFormula::formulaString ( ) const

inline

Definition at line 81 of file RooFormula.h.

◆ getParameter() [1/2]

RooAbsArg * RooFormula::getParameter ( const char * name ) const

inline

Return pointer to the parameter with given name.

Returns: Parameter if in use, nullptr if not in use.

Definition at line 49 of file RooFormula.h.

◆ getParameter() [2/2]

RooAbsArg * RooFormula::getParameter ( Int_t index ) const

inline

Return pointer to parameter at given index.

This returns irrespective of whether the parameter is in use.

Definition at line 55 of file RooFormula.h.

◆ installFormulaOrThrow()

void RooFormula::installFormulaOrThrow ( const std::string & formulaa )

private

Check that the formula compiles, and also fulfills the assumptions.

Definition at line 477 of file RooFormula.cxx.

◆ ok()

Bool_t RooFormula::ok ( ) const

inline

Definition at line 59 of file RooFormula.h.

◆ operator=()

RooFormula & RooFormula::operator= ( const RooFormula & other )

private

◆ Print()

virtual void RooFormula::Print ( Option_t * option = 0 ) const

inlinevirtual

Print TNamed name and title.

Reimplemented from TNamed.

Definition at line 76 of file RooFormula.h.

◆ printArgs()

void RooFormula::printArgs ( std::ostream & os ) const

virtual

Print arguments of formula, i.e. dependents that are actually used.

Reimplemented from RooPrintable.

Definition at line 464 of file RooFormula.cxx.

◆ printClassName()

void RooFormula::printClassName ( std::ostream & os ) const

virtual

Print class name of formula.

Reimplemented from RooPrintable.

Definition at line 455 of file RooFormula.cxx.

◆ printMultiline()

void RooFormula::printMultiline	(	std::ostream &	os,
		Int_t	contents,
		Bool_t	verbose = `kFALSE`,
		TString	indent = `""`
	)		const

virtual

Printing interface.

Reimplemented from RooPrintable.

Definition at line 414 of file RooFormula.cxx.

◆ printName()

void RooFormula::printName ( std::ostream & os ) const

virtual

Print name of formula.

Reimplemented from RooPrintable.

Definition at line 437 of file RooFormula.cxx.

◆ printTitle()

void RooFormula::printTitle ( std::ostream & os ) const

virtual

Print title of formula.

Reimplemented from RooPrintable.

Definition at line 446 of file RooFormula.cxx.

◆ printValue()

void RooFormula::printValue ( std::ostream & os ) const

virtual

Print value of formula.

Reimplemented from RooPrintable.

Definition at line 428 of file RooFormula.cxx.

◆ processFormula()

std::string RooFormula::processFormula ( std::string formula ) const

private

Process given formula by replacing all ordinal and name references by x[i], where i matches the position of the argument in _origList.

Further, references to category states such as leptonMulti:one are replaced by the category index.

Definition at line 155 of file RooFormula.cxx.

◆ reCompile()

Bool_t RooFormula::reCompile ( const char * newFormula )

Recompile formula with new expression.

In case of error, the old formula is retained.

Definition at line 281 of file RooFormula.cxx.

◆ reconstructFormula()

std::string RooFormula::reconstructFormula ( std::string internalRepr ) const

private

From the internal representation, construct a formula by replacing all index place holders with the names of the variables that are being used to evaluate it.

Definition at line 259 of file RooFormula.cxx.

◆ usedVariables()

RooArgList RooFormula::usedVariables ( ) const

private

Analyse internal formula to find out which variables are actually in use.

Definition at line 229 of file RooFormula.cxx.

Member Data Documentation

◆ _isCategory

std::vector<bool> RooFormula::_isCategory

private

Original list of dependents.

Definition at line 93 of file RooFormula.h.

◆ _origList

RooArgList RooFormula::_origList

private

Definition at line 92 of file RooFormula.h.

◆ _tFormula

std::unique_ptr<TFormula> RooFormula::_tFormula

private

Whether an element of the _origList is a category.

Definition at line 94 of file RooFormula.h.

Libraries for RooFormula:

[legend]

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

roofit/roofitcore/inc/RooFormula.h
roofit/roofitcore/src/RooFormula.cxx

Category expressions

Debugging a formula that won't compile

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ RooFormula() [1/3]

◆ RooFormula() [2/3]

◆ RooFormula() [3/3]

Member Function Documentation

◆ actualDependents()

◆ changeDependents()

◆ Clone()

◆ dump()

◆ eval()

◆ evaluateSpan()

◆ formulaString()

◆ getParameter() [1/2]

◆ getParameter() [2/2]

◆ installFormulaOrThrow()

◆ ok()

◆ operator=()

◆ Print()

◆ printArgs()

◆ printClassName()

◆ printMultiline()

◆ printName()

◆ printTitle()

◆ printValue()

◆ processFormula()

◆ reCompile()

◆ reconstructFormula()

◆ usedVariables()

Member Data Documentation

◆ _isCategory

◆ _origList

◆ _tFormula