 ROOT   6.10/09 Reference Guide

The Formula class.

This is a new version of the TFormula class based on Cling. This class is not 100% backward compatible with the old TFormula class, which is still available in ROOT as ROOT::v5::TFormula. Some of the TFormula member funtions available in version 5, such as Analyze and AnalyzeFunction are not available in the new TFormula. On the other hand formula expressions which were valid in version 5 are still valid in TFormula version 6

This class has been implemented during Google Summer of Code 2013 by Maciej Zimnoch.

### Example of valid expressions:

• sin(x)/x
• *sin(x) + *exp(-*x)
• x + y**2
• x^2 + y^2
• *pow(,4)
• 2*pi*sqrt(x/y)
• gaus(0)*expo(3) + ypol3(5)*x
• gausn(0)*expo(3) + ypol3(5)*x

In the last example above:

• gaus(0) is a substitute for *exp(-0.5*((x-)/)**2) and (0) means start numbering parameters at 0
• gausn(0) is a substitute for *exp(-0.5*((x-)/)**2)/(sqrt(2*pi)*)) and (0) means start numbering parameters at 0
• expo(3) is a substitute for exp(+*x
• pol3(5) is a substitute for par+par*x+par*x**2+par*x**3 (PolN stands for Polynomial of degree N)

TMath functions can be part of the expression, eg:

• TMath::Landau(x)*sin(x)
• TMath::Erf(x)

Formula may contain constans, eg:

• sqrt2
• e
• pi
• ln10
• infinity

and more.

Comparisons operators are also supported (&&, ||, ==, <=, >=, !)

Examples:

sin(x*(x<0.5 || x>1))

If the result of a comparison is TRUE, the result is 1, otherwise 0.

Already predefined names can be given. For example, if the formula

TFormula old("old",sin(x*(x<0.5 || x>1)))

one can assign a name to the formula. By default the name of the object = title = formula itself.

TFormula new("new","x*old")

is equivalent to:

TFormula new("new","x*sin(x*(x&lt;0.5 || x&gt;1))")

The class supports unlimited numer of variables and parameters. By default the names which can be used for the variables are x,y,z,t or x,x,x,x,....x[N] for N-dimensionals formula.

This class is not anymore the base class for the function classes TF1, but it has now adata member of TF1 which can be access via TF1::GetFormula.

Definition at line 83 of file TFormula.h.

## Public Types

enum  { kNotGlobal = BIT(10), kNormalized = BIT(14), kLinear = BIT(16), kLambda = BIT(17) } Public Types inherited from TObject
enum  { kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff }

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

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

## Public Member Functions

TFormula ()

TFormula (const char *name, const char *formula="", bool addToGlobList=true)

TFormula (const char *name, const char *formula, int ndim, int npar, bool addToGlobList=true)
Constructor from a full compileable C++ expression. More...

TFormula (const TFormula &formula)

virtual ~TFormula ()

void AddParameter (const TString &name, Double_t value=0)

void AddVariable (const TString &name, Double_t value=0)
Adds variable to known variables, and reprocess formula. More...

void AddVariables (const TString *vars, const Int_t size)

virtual void Clear (Option_t *option="")
Clear the formula setting expression to empty and reset the variables and parameters containers. More...

Int_t Compile (const char *expression="")
Compile the given expression with Cling backward compatibility method to be used in combination with the empty constructor if no expression is given , the current stored formula (retrieved with GetExpFormula()) or the title is used. More...

virtual void Copy (TObject &f1) const
Copy this to obj. More...

Double_t Eval (Double_t x) const
Sets first variable (e.g. x) and evaluate formula. More...

Double_t Eval (Double_t x, Double_t y) const
Sets first 2 variables (e.g. x and y) and evaluate formula. More...

Double_t Eval (Double_t x, Double_t y, Double_t z) const
Sets first 3 variables (e.g. x, y, z) and evaluate formula. More...

Double_t Eval (Double_t x, Double_t y, Double_t z, Double_t t) const
Sets first 4 variables (e.g. x, y, z, t) and evaluate formula. More...

Double_t EvalPar (const Double_t *x, const Double_t *params=0) const

TString GetExpFormula (Option_t *option="") const
Return the expression formula. More...

const TObjectGetLinearPart (Int_t i) const
Return linear part. More...

Int_t GetNdim () const

Int_t GetNpar () const

Int_t GetNumber () const

Double_t GetParameter (const char *name) const
Returns parameter value given by string. More...

Double_t GetParameter (Int_t param) const
Return parameter value given by integer. More...

Double_tGetParameters () const

void GetParameters (Double_t *params) const

const char * GetParName (Int_t ipar) const
Return parameter name given by integer. More...

Int_t GetParNumber (const char *name) const
Return parameter index given a name (return -1 for not existing parameters) non need to print an error. More...

Double_t GetVariable (const char *name) const
Returns variable value. More...

TString GetVarName (Int_t ivar) const
Returns variable name given its position in the array. More...

Int_t GetVarNumber (const char *name) const
Returns variable number (positon in array) given its name. More...

Bool_t IsLinear () const

Bool_t IsValid () const

TFormulaoperator= (const TFormula &rhs)
= operator. More...

void Print (Option_t *option="") const
Print the formula and its attributes. More...

void SetName (const char *name)
Set the name of the formula. More...

void SetParameter (const char *name, Double_t value)
Sets parameter value. More...

void SetParameter (Int_t param, Double_t value)
Set a parameter given a parameter index The parameter index is by default the aphabetic order given to the parameters apart if the users has defined explicitly the parameter names. More...

void SetParameters (const Double_t *params)
Set a vector of parameters value. More...

void SetParameters (Double_t p0, Double_t p1, Double_t p2=0, Double_t p3=0, Double_t p4=0, Double_t p5=0, Double_t p6=0, Double_t p7=0, Double_t p8=0, Double_t p9=0, Double_t p10=0)
Set a list of parameters. More...

void SetParName (Int_t ipar, const char *name)

void SetParNames (const char *name0="p0", const char *name1="p1", const char *name2="p2", const char *name3="p3", const char *name4="p4", const char *name5="p5", const char *name6="p6", const char *name7="p7", const char *name8="p8", const char *name9="p9", const char *name10="p10")

void SetVariable (const TString &name, Double_t value)
Sets variable value. More...

void SetVariables (const std::pair< TString, Double_t > *vars, const Int_t size)
Sets multiple variables. More... Public Member Functions inherited from TNamed
TNamed ()

TNamed (const char *name, const char *title)

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

TNamed (const TNamed &named)
TNamed copy ctor. More...

virtual ~TNamed ()

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 two TNamed objects. More...

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

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

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

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

virtual Bool_t IsSortable () const

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

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

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

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

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

Append graphics object to current pad. More...

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

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

Bool_t IsOnHeap () const

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). 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 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, Bool_t set)
Set or unset the user status bits as specified in f. More...

void SetBit (UInt_t f)

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...

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...

## Protected Member Functions

void DoAddParameter (const TString &name, Double_t value, bool processFormula)
Adds parameter to known parameters. More...

Double_t DoEval (const Double_t *x, const Double_t *p=nullptr) const
Evaluate formula. More...

void DoSetParameters (const Double_t *p, Int_t size)

void ExtractFunctors (TString &formula)
Extracts functors from formula, and put them in fFuncs. More...

Bool_t PrepareFormula (TString &formula)
prepare the formula to be executed normally is called with fFormula More...

void PreProcessFormula (TString &formula)
Preprocessing of formula Replace all ** by ^, and removes spaces. More...

void ProcessFormula (TString &formula)
Iterates through funtors in fFuncs and performs the appropriate action. More...

void ReplaceParamName (TString &formula, const TString &oldname, const TString &name)
Replace in Formula expression the parameter name. More...

void SetPredefinedParamNames ()
Set parameter names only in case of pre-defined functions. 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 ()

## Static Protected Member Functions

static Bool_t IsAParameterName (const TString &formula, int ipos)

static Bool_t IsBracket (const char c)

static Bool_t IsFunctionNameChar (const char c)

static Bool_t IsHexadecimal (const TString &formula, int ipos)

static Bool_t IsOperator (const char c)

static Bool_t IsScientificNotation (const TString &formula, int ipos)

## Protected Attributes

std::map< TString, Double_tfConsts

TString fFormula

std::list< TFormulaFunctionfFuncs

std::map< TString, TStringfFunctionsShortcuts

std::vector< TObject * > fLinearParts

Int_t fNdim

Int_t fNpar

Int_t fNumber

std::map< TString, Int_t, TFormulaParamOrderfParams
list of variable names More...

std::map< TString, TFormulaVariablefVars Protected Attributes inherited from TNamed
TString fName

TString fTitle

## Private Member Functions

void FillDefaults ()
Fill structures with default variables, constants and function shortcuts. More...

void HandleExponentiation (TString &formula)
Handling exponentiation Can handle multiple carets, eg. More...

void HandleLinear (TString &formula)
Handle linear functions defined with the operator ++. More...

void HandleParametrizedFunctions (TString &formula)
Handling parametrized functions Function can be normalized, and have different variable then x. More...

void HandlePolN (TString &formula)
Handling polN If before 'pol' exist any name, this name will be treated as variable used in polynomial eg. More...

Bool_t InitLambdaExpression (const char *formula)

void InputFormulaIntoCling ()
pointer to the lambda function More...

Bool_t PrepareEvalMethod ()
Sets TMethodCall to function inside Cling environment. More...

## Static Private Member Functions

static Bool_t IsDefaultVariableName (const TString &name)

## Private Attributes

transient to force re-initialization More...

Bool_t fClingInitialized
trasient to force initialization More...

TString fClingInput

TString fClingName
pointer to methocall More...

std::vector< Double_tfClingParameters
cached variables More...

std::vector< Double_tfClingVariables
input function passed to Cling More...

TInterpreter::CallFuncIFacePtr_t::Generic_t fFuncPtr
unique name passed to Cling to define the function ( double clingName(double*x, double*p) ) More...

voidfLambdaPtr
function pointer More...

TMethodCallfMethod 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...

#include "inc/TFormula.h"

Inheritance diagram for TFormula:
[legend]

## ◆ anonymous enum

 anonymous enum
Enumerator
kNotGlobal
kNormalized
kLinear
kLambda

Definition at line 142 of file TFormula.h.

## ◆ TFormula() [1/4]

 TFormula::TFormula ( )

Definition at line 265 of file TFormula.cxx.

## ◆ ~TFormula()

 TFormula::~TFormula ( )
virtual

Definition at line 292 of file TFormula.cxx.

## ◆ TFormula() [2/4]

 TFormula::TFormula ( const char * name, const char * formula = "", bool addToGlobList = true )

Definition at line 313 of file TFormula.cxx.

## ◆ TFormula() [3/4]

 TFormula::TFormula ( const char * name, const char * formula, int ndim, int npar, bool addToGlobList = true )

Constructor from a full compileable C++ expression.

Definition at line 356 of file TFormula.cxx.

## ◆ TFormula() [4/4]

 TFormula::TFormula ( const TFormula & formula )

Definition at line 402 of file TFormula.cxx.

## Member Function Documentation

 void TFormula::AddParameter ( const TString & name, Double_t value = 0 )
inline

Definition at line 156 of file TFormula.h.

 void TFormula::AddVariable ( const TString & name, Double_t value = 0 )

Adds variable to known variables, and reprocess formula.

Definition at line 2059 of file TFormula.cxx.

 void TFormula::AddVariables ( const TString * vars, const Int_t size )

First argument is an array of pairs<TString,Double>, where first argument is name of variable, second argument represents value. size - number of variables passed in first argument

Definition at line 2098 of file TFormula.cxx.

## ◆ Clear()

 void TFormula::Clear ( Option_t * option = "" )
virtual

Clear the formula setting expression to empty and reset the variables and parameters containers.

Reimplemented from TNamed.

Definition at line 621 of file TFormula.cxx.

## ◆ Compile()

 Int_t TFormula::Compile ( const char * expression = "" )

Compile the given expression with Cling backward compatibility method to be used in combination with the empty constructor if no expression is given , the current stored formula (retrieved with GetExpFormula()) or the title is used.

return 0 if the formula compilation is successfull

Definition at line 510 of file TFormula.cxx.

## ◆ Copy()

 void TFormula::Copy ( TObject & named ) const
virtual

Copy this to obj.

Reimplemented from TNamed.

Definition at line 544 of file TFormula.cxx.

 void TFormula::DoAddParameter ( const TString & name, Double_t value, bool processFormula )
protected

User should use SetParameter, because parameters are added during initialization part, and after that adding new will be pointless.

Definition at line 2250 of file TFormula.cxx.

## ◆ DoEval()

 Double_t TFormula::DoEval ( const Double_t * x, const Double_t * p = nullptr ) const
protected

Evaluate formula.

If formula is not ready to execute(missing parameters/variables), print these which are not known. If parameter has default value, and has not been setted, appropriate warning is shown.

Definition at line 2655 of file TFormula.cxx.

## ◆ DoSetParameters()

 void TFormula::DoSetParameters ( const Double_t * p, Int_t size )
protected

Definition at line 2467 of file TFormula.cxx.

## ◆ Eval() [1/4]

 Double_t TFormula::Eval ( Double_t x ) const

Sets first variable (e.g. x) and evaluate formula.

Definition at line 2642 of file TFormula.cxx.

## ◆ Eval() [2/4]

 Double_t TFormula::Eval ( Double_t x, Double_t y ) const

Sets first 2 variables (e.g. x and y) and evaluate formula.

Definition at line 2633 of file TFormula.cxx.

## ◆ Eval() [3/4]

 Double_t TFormula::Eval ( Double_t x, Double_t y, Double_t z ) const

Sets first 3 variables (e.g. x, y, z) and evaluate formula.

Definition at line 2624 of file TFormula.cxx.

## ◆ Eval() [4/4]

 Double_t TFormula::Eval ( Double_t x, Double_t y, Double_t z, Double_t t ) const

Sets first 4 variables (e.g. x, y, z, t) and evaluate formula.

Definition at line 2615 of file TFormula.cxx.

## ◆ EvalPar()

 Double_t TFormula::EvalPar ( const Double_t * x, const Double_t * params = 0 ) const

Definition at line 2607 of file TFormula.cxx.

## ◆ ExtractFunctors()

 void TFormula::ExtractFunctors ( TString & formula )
protected

Extracts functors from formula, and put them in fFuncs.

Simple grammar:

• <function> := name(arg1,arg2...)
• <variable> := name
• <parameter> := [number]
• <name> := String containing lower and upper letters, numbers, underscores
• <number> := Integer number Operators are omitted.

Definition at line 1410 of file TFormula.cxx.

## ◆ FillDefaults()

 void TFormula::FillDefaults ( )
private

Fill structures with default variables, constants and function shortcuts.

Definition at line 726 of file TFormula.cxx.

## ◆ GetExpFormula()

 TString TFormula::GetExpFormula ( Option_t * option = "" ) const

Return the expression formula.

• If option = "P" replace the parameter names with their values
• If option = "CLING" return the actual expression used to build the function passed to cling
• If option = "CLINGP" replace in the CLING expression the parameter with their values

Definition at line 2712 of file TFormula.cxx.

## ◆ GetLinearPart()

 const TObject * TFormula::GetLinearPart ( Int_t i ) const

Return linear part.

Definition at line 2043 of file TFormula.cxx.

## ◆ GetNdim()

 Int_t TFormula::GetNdim ( ) const
inline

Definition at line 169 of file TFormula.h.

## ◆ GetNpar()

 Int_t TFormula::GetNpar ( ) const
inline

Definition at line 170 of file TFormula.h.

## ◆ GetNumber()

 Int_t TFormula::GetNumber ( ) const
inline

Definition at line 171 of file TFormula.h.

## ◆ GetParameter() [1/2]

 Double_t TFormula::GetParameter ( const char * name ) const

Returns parameter value given by string.

Definition at line 2344 of file TFormula.cxx.

## ◆ GetParameter() [2/2]

 Double_t TFormula::GetParameter ( Int_t param ) const

Return parameter value given by integer.

Definition at line 2358 of file TFormula.cxx.

## ◆ GetParameters() [1/2]

 Double_t * TFormula::GetParameters ( ) const

Definition at line 2384 of file TFormula.cxx.

## ◆ GetParameters() [2/2]

 void TFormula::GetParameters ( Double_t * params ) const

Definition at line 2391 of file TFormula.cxx.

## ◆ GetParName()

 const char * TFormula::GetParName ( Int_t ipar ) const

Return parameter name given by integer.

Definition at line 2370 of file TFormula.cxx.

## ◆ GetParNumber()

 Int_t TFormula::GetParNumber ( const char * name ) const

Return parameter index given a name (return -1 for not existing parameters) non need to print an error.

Definition at line 2331 of file TFormula.cxx.

## ◆ GetVariable()

 Double_t TFormula::GetVariable ( const char * name ) const

Returns variable value.

Definition at line 2190 of file TFormula.cxx.

## ◆ GetVarName()

 TString TFormula::GetVarName ( Int_t ivar ) const

Returns variable name given its position in the array.

Definition at line 2218 of file TFormula.cxx.

## ◆ GetVarNumber()

 Int_t TFormula::GetVarNumber ( const char * name ) const

Returns variable number (positon in array) given its name.

Definition at line 2204 of file TFormula.cxx.

## ◆ HandleExponentiation()

 void TFormula::HandleExponentiation ( TString & formula )
private

Handling exponentiation Can handle multiple carets, eg.

2^3^4 will be treated like 2^(3^4)

Definition at line 1199 of file TFormula.cxx.

## ◆ HandleLinear()

 void TFormula::HandleLinear ( TString & formula )
private

Handle linear functions defined with the operator ++.

Definition at line 1296 of file TFormula.cxx.

## ◆ HandleParametrizedFunctions()

 void TFormula::HandleParametrizedFunctions ( TString & formula )
private

Handling parametrized functions Function can be normalized, and have different variable then x.

Variables should be placed in brackets after function name. No brackets are treated like [x]. Normalized function has char 'n' after name, eg. gausn[var](0) will be replaced with *exp(-0.5*((var-)/)^2)/(sqrt(2*pi)*)

• Key for function map is pair of name and dimension of function
• value of key is a pair function body and normalized function body
• {Vn} is a place where variable appear, n represents n-th variable from variable list. Count starts from 0.
• [num] stands for parameter number. If user pass to function argument 5, num will stand for (5 + num) parameter.

Definition at line 940 of file TFormula.cxx.

## ◆ HandlePolN()

 void TFormula::HandlePolN ( TString & formula )
private

Handling polN If before 'pol' exist any name, this name will be treated as variable used in polynomial eg.

varpol2(5) will be replaced with:  + *var + *var^2 Empty name is treated like variable x.

Definition at line 828 of file TFormula.cxx.

## ◆ InitLambdaExpression()

 Bool_t TFormula::InitLambdaExpression ( const char * formula )
private

Definition at line 469 of file TFormula.cxx.

## ◆ InputFormulaIntoCling()

 void TFormula::InputFormulaIntoCling ( )
private

pointer to the lambda function

Inputs formula, transfered to C++ code into Cling.

Definition at line 713 of file TFormula.cxx.

## ◆ IsAParameterName()

 Bool_t TFormula::IsAParameterName ( const TString & formula, int ipos )
staticprotected

Definition at line 211 of file TFormula.cxx.

## ◆ IsBracket()

 Bool_t TFormula::IsBracket ( const char c )
staticprotected

Definition at line 153 of file TFormula.cxx.

## ◆ IsDefaultVariableName()

 Bool_t TFormula::IsDefaultVariableName ( const TString & name )
staticprivate

Definition at line 170 of file TFormula.cxx.

## ◆ IsFunctionNameChar()

 Bool_t TFormula::IsFunctionNameChar ( const char c )
staticprotected

Definition at line 164 of file TFormula.cxx.

 Bool_t TFormula::IsHexadecimal ( const TString & formula, int ipos )
staticprotected

Definition at line 188 of file TFormula.cxx.

## ◆ IsLinear()

 Bool_t TFormula::IsLinear ( ) const
inline

Definition at line 182 of file TFormula.h.

## ◆ IsOperator()

 Bool_t TFormula::IsOperator ( const char c )
staticprotected

Definition at line 141 of file TFormula.cxx.

## ◆ IsScientificNotation()

 Bool_t TFormula::IsScientificNotation ( const TString & formula, int ipos )
staticprotected

Definition at line 176 of file TFormula.cxx.

## ◆ IsValid()

 Bool_t TFormula::IsValid ( ) const
inline

Definition at line 181 of file TFormula.h.

## ◆ operator=()

 TFormula & TFormula::operator= ( const TFormula & rhs )

= operator.

Definition at line 459 of file TFormula.cxx.

## ◆ PrepareEvalMethod()

 bool TFormula::PrepareEvalMethod ( )
private

Sets TMethodCall to function inside Cling environment.

TFormula uses it to execute function. After call, TFormula should be ready to evaluate formula.

Definition at line 658 of file TFormula.cxx.

## ◆ PrepareFormula()

 Bool_t TFormula::PrepareFormula ( TString & formula )
protected

prepare the formula to be executed normally is called with fFormula

Definition at line 1371 of file TFormula.cxx.

## ◆ PreProcessFormula()

 void TFormula::PreProcessFormula ( TString & formula )
protected

Preprocessing of formula Replace all ** by ^, and removes spaces.

Handle also parametrized functions like polN,gaus,expo,landau and exponentiation. Similar functionality should be added here.

Definition at line 1351 of file TFormula.cxx.

## ◆ Print()

 void TFormula::Print ( Option_t * option = "" ) const
virtual

Print the formula and its attributes.

Reimplemented from TNamed.

Definition at line 2785 of file TFormula.cxx.

## ◆ ProcessFormula()

 void TFormula::ProcessFormula ( TString & formula )
protected

Iterates through funtors in fFuncs and performs the appropriate action.

If functor has 0 arguments (has only name) can be:

• variable
• will be replaced with x[num], where x is an array containing value of this variable under num.
• pre-defined formula
• will be replaced with formulas body
• constant
• will be replaced with constant value
• parameter
• will be replaced with p[num], where p is an array containing value of this parameter under num. If has arguments it can be :
• function shortcut, eg. sin
• will be replaced with fullname of function, eg. sin -> TMath::Sin
• function from cling environment, eg. TMath::BreitWigner(x,y,z)
• first check if function exists, and has same number of arguments, then accept it and set as found. If all functors after iteration are matched with corresponding action, it inputs C++ code of formula into cling, and sets flag that formula is ready to evaluate.

Definition at line 1637 of file TFormula.cxx.

## ◆ ReplaceParamName()

 void TFormula::ReplaceParamName ( TString & formula, const TString & oldname, const TString & name )
protected

Replace in Formula expression the parameter name.

Definition at line 2579 of file TFormula.cxx.

## ◆ SetName()

 void TFormula::SetName ( const char * name )
virtual

Set the name of the formula.

We need to allow the list of function to properly handle the hashes.

Reimplemented from TNamed.

Definition at line 2142 of file TFormula.cxx.

## ◆ SetParameter() [1/2]

 void TFormula::SetParameter ( const char * name, Double_t value )

Sets parameter value.

Definition at line 2405 of file TFormula.cxx.

## ◆ SetParameter() [2/2]

 void TFormula::SetParameter ( Int_t param, Double_t value )

Set a parameter given a parameter index The parameter index is by default the aphabetic order given to the parameters apart if the users has defined explicitly the parameter names.

Definition at line 2521 of file TFormula.cxx.

## ◆ SetParameters() [1/2]

 void TFormula::SetParameters ( const Double_t * params )

Set a vector of parameters value.

Order in the vector is by default the aphabetic order given to the parameters apart if the users has defined explicitly the parameter names

Definition at line 2489 of file TFormula.cxx.

## ◆ SetParameters() [2/2]

 void TFormula::SetParameters ( Double_t p0, Double_t p1, Double_t p2 = 0, Double_t p3 = 0, Double_t p4 = 0, Double_t p5 = 0, Double_t p6 = 0, Double_t p7 = 0, Double_t p8 = 0, Double_t p9 = 0, Double_t p10 = 0 )

Set a list of parameters.

The order is by default the aphabetic order given to the parameters apart if the users has defined explicitly the parameter names

Definition at line 2499 of file TFormula.cxx.

## ◆ SetParName()

 void TFormula::SetParName ( Int_t ipar, const char * name )

Definition at line 2549 of file TFormula.cxx.

## ◆ SetParNames()

 void TFormula::SetParNames ( const char * name0 = "p0", const char * name1 = "p1", const char * name2 = "p2", const char * name3 = "p3", const char * name4 = "p4", const char * name5 = "p5", const char * name6 = "p6", const char * name7 = "p7", const char * name8 = "p8", const char * name9 = "p9", const char * name10 = "p10" )

Definition at line 2531 of file TFormula.cxx.

## ◆ SetPredefinedParamNames()

 void TFormula::SetPredefinedParamNames ( )
protected

Set parameter names only in case of pre-defined functions.

Definition at line 1971 of file TFormula.cxx.

## ◆ SetVariable()

 void TFormula::SetVariable ( const TString & name, Double_t value )

Sets variable value.

Definition at line 2234 of file TFormula.cxx.

## ◆ SetVariables()

 void TFormula::SetVariables ( const std::pair< TString, Double_t > * vars, const Int_t size )

Sets multiple variables.

First argument is an array of pairs<TString,Double>, where first argument is name of variable, second argument represents value. size - number of variables passed in first argument

Definition at line 2170 of file TFormula.cxx.

## Member Data Documentation

private

transient to force re-initialization

Definition at line 94 of file TFormula.h.

## ◆ fClingInitialized

 Bool_t TFormula::fClingInitialized
private

trasient to force initialization

Definition at line 93 of file TFormula.h.

## ◆ fClingInput

 TString TFormula::fClingInput
private

Definition at line 89 of file TFormula.h.

## ◆ fClingName

 TString TFormula::fClingName
private

pointer to methocall

Definition at line 96 of file TFormula.h.

## ◆ fClingParameters

 std::vector TFormula::fClingParameters
private

cached variables

Definition at line 91 of file TFormula.h.

## ◆ fClingVariables

 std::vector TFormula::fClingVariables
private

input function passed to Cling

Definition at line 90 of file TFormula.h.

## ◆ fConsts

 std::map TFormula::fConsts
protected

Definition at line 115 of file TFormula.h.

## ◆ fFormula

 TString TFormula::fFormula
protected

Definition at line 117 of file TFormula.h.

## ◆ fFuncPtr

 TInterpreter::CallFuncIFacePtr_t::Generic_t TFormula::fFuncPtr
private

unique name passed to Cling to define the function ( double clingName(double*x, double*p) )

Definition at line 98 of file TFormula.h.

## ◆ fFuncs

 std::list TFormula::fFuncs
protected

Definition at line 112 of file TFormula.h.

## ◆ fFunctionsShortcuts

 std::map TFormula::fFunctionsShortcuts
protected

Definition at line 116 of file TFormula.h.

## ◆ fLambdaPtr

 void* TFormula::fLambdaPtr
private

function pointer

Definition at line 99 of file TFormula.h.

## ◆ fLinearParts

 std::vector TFormula::fLinearParts
protected

Definition at line 121 of file TFormula.h.

## ◆ fMethod

 TMethodCall* TFormula::fMethod
private

Definition at line 95 of file TFormula.h.

## ◆ fNdim

 Int_t TFormula::fNdim
protected

Definition at line 118 of file TFormula.h.

## ◆ fNpar

 Int_t TFormula::fNpar
protected

Definition at line 119 of file TFormula.h.

## ◆ fNumber

 Int_t TFormula::fNumber
protected

Definition at line 120 of file TFormula.h.

## ◆ fParams

 std::map TFormula::fParams
protected

list of variable names

Definition at line 114 of file TFormula.h.