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RooFormula Class Reference

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))
RooArgList is a container object that can hold multiple RooAbsArg objects.
Definition RooArgList.h:22
Internally uses ROOT's TFormula to compute user-defined expressions of RooAbsArgs.
Definition RooFormula.h:27
Double_t y[n]
Definition legend1.C:17
Double_t x[n]
Definition legend1.C:17

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 27 of file RooFormula.h.

Public Member Functions

 RooFormula (const char *name, const char *formula, const RooArgList &varList, bool checkVariables=true)
 Construct a new formula.
 
 RooFormula (const RooFormula &other, const char *name=nullptr)
 Copy constructor.
 
RooArgSet actualDependents () const
 Return list of arguments which are used in the formula.
 
bool changeDependents (const RooAbsCollection &newDeps, bool mustReplaceAll, bool nameChange)
 Change used variables to those with the same name in given list.
 
TObjectClone (const char *newName=nullptr) const override
 Make a clone of an object using the Streamer facility.
 
void doEval (RooFit::EvalContext &) const
 
void dump () const
 DEBUG: Dump state information.
 
double eval (const RooArgSet *nset=nullptr) const
 Evaluate all parameters/observables, and then evaluate formula.
 
std::string formulaString () const
 
RooAbsArggetParameter (const char *name) const
 Return pointer to the parameter with given name.
 
RooAbsArggetParameter (Int_t index) const
 Return pointer to parameter at given index.
 
TFormulagetTFormula () const
 
bool ok () const
 
RooFormulaoperator= (const RooFormula &other)=delete
 
RooFormulaoperator= (RooFormula &&other)=delete
 
void Print (Option_t *options=nullptr) const override
 This method must be overridden when a class wants to print itself.
 
void printArgs (std::ostream &os) const override
 Print arguments of formula, i.e. dependents that are actually used.
 
void printClassName (std::ostream &os) const override
 Print class name of formula.
 
void printMultiline (std::ostream &os, Int_t contents, bool verbose=false, TString indent="") const override
 Printing interface.
 
void printName (std::ostream &os) const override
 Print name of formula.
 
void printTitle (std::ostream &os) const override
 Print title of formula.
 
void printValue (std::ostream &os) const override
 Print value of formula.
 
- 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.
 
void Clear (Option_t *option="") override
 Set name and title to empty strings ("").
 
TObjectClone (const char *newname="") const override
 Make a clone of an object using the Streamer facility.
 
Int_t Compare (const TObject *obj) const override
 Compare two TNamed objects.
 
void Copy (TObject &named) const override
 Copy this to obj.
 
virtual void FillBuffer (char *&buffer)
 Encode TNamed into output buffer.
 
const char * GetName () const override
 Returns name of object.
 
const char * GetTitle () const override
 Returns title of object.
 
ULong_t Hash () const override
 Return hash value for this object.
 
TClassIsA () const override
 
Bool_t IsSortable () const override
 
void ls (Option_t *option="") const override
 List TNamed name and title.
 
TNamedoperator= (const TNamed &rhs)
 TNamed assignment operator.
 
void Print (Option_t *option="") const override
 Print TNamed name and title.
 
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.
 
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.
 
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 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 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 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)
 
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
 
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 (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, void *vp)
 Only called by placement new when throwing an exception.
 
void operator delete[] (void *ptr)
 Operator delete [].
 
void operator delete[] (void *ptr, void *vp)
 Only called by placement new[] when throwing an exception.
 
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 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.
 
- 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 TClassIsA () 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.
 
virtual void Streamer (TBuffer &)
 
void StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)
 

Private Member Functions

void installFormulaOrThrow (const std::string &formulaa)
 Check that the formula compiles, and also fulfills the assumptions.
 
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
 ! Whether an element of the _origList is a category.
 
RooArgList _origList
 ! Original list of dependents
 
std::unique_ptr< TFormula_tFormula
 ! The formula used to compute values
 

Additional Inherited Members

- Public Types inherited from TObject
enum  {
  kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 ,
  kBitMask = 0x00ffffff
}
 
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 ))
}
 
- 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 TNamed
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.
 
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 TClassClass ()
 
static const char * Class_Name ()
 
static constexpr Version_t Class_Version ()
 
static const char * DeclFileName ()
 
static std::ostream & defaultPrintStream (std::ostream *os=nullptr)
 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 = (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).
 
void MakeZombie ()
 
- Protected Attributes inherited from TNamed
TString fName
 
TString fTitle
 
- Static Protected Attributes inherited from RooPrintable
static Int_t _nameLength
 

#include </home/sftnight/build/workspace/root-makedoc-master/rootspi/rdoc/src/master/roofit/roofitcore/src/RooFormula.h>

Inheritance diagram for RooFormula:
[legend]

Constructor & Destructor Documentation

◆ RooFormula() [1/2]

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

Construct a new formula.

Parameters
[in]nameName of the formula.
[in]formulaFormula to be evaluated. Parameters/observables are identified by name or ordinal position in varList.
[in]varListList of variables to be passed to the formula.
[in]checkVariablesUnused parameter.

Definition at line 194 of file RooFormula.cxx.

◆ RooFormula() [2/2]

RooFormula::RooFormula ( const RooFormula other,
const char *  name = nullptr 
)

Copy constructor.

Definition at line 205 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 39 of file RooFormula.h.

◆ changeDependents()

bool RooFormula::changeDependents ( const RooAbsCollection newDeps,
bool  mustReplaceAll,
bool  nameChange 
)

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

Parameters
[in]newDepsNew dependents to replace the old ones.
[in]mustReplaceAllWill yield an error if one dependent does not have a replacement.
[in]nameChangePassed down to RooAbsArg::findNewServer(const RooAbsCollection&, bool) const.

Definition at line 344 of file RooFormula.cxx.

◆ Clone()

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

Make a clone of an object using the Streamer facility.

If the object derives from TNamed, this function is called by TNamed::Clone. TNamed::Clone uses the optional argument to set a new name to the newly created object.

If the object class has a DirectoryAutoAdd function, it will be called at the end of the function with the parameter gDirectory. This usually means that the object will be appended to the current ROOT directory.

Reimplemented from TObject.

Definition at line 32 of file RooFormula.h.

◆ doEval()

void RooFormula::doEval ( RooFit::EvalContext ctx) const

Definition at line 407 of file RooFormula.cxx.

◆ dump()

void RooFormula::dump ( ) const

DEBUG: Dump state information.

Definition at line 333 of file RooFormula.cxx.

◆ eval()

double RooFormula::eval ( const RooArgSet nset = nullptr) const

Evaluate 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]nsetNormalisation set passed to evaluation of arguments serving values.
Returns
The result of the evaluation.

Definition at line 382 of file RooFormula.cxx.

◆ formulaString()

std::string RooFormula::formulaString ( ) const
inline

Definition at line 71 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 44 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 48 of file RooFormula.h.

◆ getTFormula()

TFormula * RooFormula::getTFormula ( ) const
inline

Definition at line 72 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 493 of file RooFormula.cxx.

◆ ok()

bool RooFormula::ok ( ) const
inline

Definition at line 50 of file RooFormula.h.

◆ operator=() [1/2]

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

◆ operator=() [2/2]

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

◆ Print()

void RooFormula::Print ( Option_t option = nullptr) const
inlineoverridevirtual

This method must be overridden when a class wants to print itself.

Reimplemented from TObject.

Definition at line 65 of file RooFormula.h.

◆ printArgs()

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

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

Reimplemented from RooPrintable.

Definition at line 480 of file RooFormula.cxx.

◆ printClassName()

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

Print class name of formula.

Reimplemented from RooPrintable.

Definition at line 471 of file RooFormula.cxx.

◆ printMultiline()

void RooFormula::printMultiline ( std::ostream &  os,
Int_t  contents,
bool  verbose = false,
TString  indent = "" 
) const
overridevirtual

Printing interface.

Reimplemented from RooPrintable.

Definition at line 430 of file RooFormula.cxx.

◆ printName()

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

Print name of formula.

Reimplemented from RooPrintable.

Definition at line 453 of file RooFormula.cxx.

◆ printTitle()

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

Print title of formula.

Reimplemented from RooPrintable.

Definition at line 462 of file RooFormula.cxx.

◆ printValue()

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

Print value of formula.

Reimplemented from RooPrintable.

Definition at line 444 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 226 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 318 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 288 of file RooFormula.cxx.

Member Data Documentation

◆ _isCategory

std::vector<bool> RooFormula::_isCategory
private

! Whether an element of the _origList is a category.

Definition at line 81 of file RooFormula.h.

◆ _origList

RooArgList RooFormula::_origList
private

! Original list of dependents

Definition at line 80 of file RooFormula.h.

◆ _tFormula

std::unique_ptr<TFormula> RooFormula::_tFormula
private

! The formula used to compute values

Definition at line 82 of file RooFormula.h.

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