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Reference Guide
List of all members | Public Types | Public Member Functions | Static Public Member Functions | Protected Types | Protected Member Functions | Protected Attributes | Private Attributes | List of all members
ROOT::v5::TFormula Class Reference

The FORMULA class (ROOT version 5)

Example of valid expressions:

In the last example above:

gaus(0) is a substitute for [0]*exp(-0.5*((x-[1])/[2])**2) and (0) means start numbering parameters at 0

gausn(0) is a substitute for [0]*exp(-0.5*((x-[1])/[2])**2)/(sqrt(2*pi)*[2])) and (0) means start numbering parameters at 0

expo(3) is a substitute for exp([3]+[4]*x)

pol3(5) is a substitute for par[5]+par[6]*x+par[7]*x**2+par[8]*x**3 (here Pol3 stands for Polynomial of degree 3)

TMath functions can be part of the expression, eg:

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(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. old.SetName("old"). then, old can be reused in a new expression. TFormula new("x*old") is equivalent to: TFormula new("x*sin(x*(x<0.5 || x>1))")

Up to 4 dimensions are supported (indicated by x, y, z, t) An expression may have 0 parameters or a list of parameters indicated by the sequence [par_number]

A graph showing the logic to compile and analyze a formula is shown in TFormula::Compile and TFormula::Analyze. Once a formula has been compiled, it can be evaluated for a given set of parameters. see graph in TFormula::EvalPar.

This class is the base class for the function classes TF1,TF2 and TF3. It is also used by the ntuple selection mechanism TNtupleFormula.

In version 7 of TFormula, the usage of fOper has been changed to improve the performance of TFormula::EvalPar. Conceptually, fOper was changed from a simple array of Int_t to an array of composite values. For example a 'ylandau(5)' operation used to be encoded as 4105; it is now encoded as (klandau >> kTFOperShit) + 5 Any class inheriting from TFormula and using directly fOper (which is now a private data member), needs to be updated to take this in consideration. The member functions recommended to set and access fOper are: SetAction, GetAction, GetActionParam For more performant access to the information, see the implementation TFormula::EvalPar

CHANGING DEFAULT SETTINGS

When creating complex formula , it may be necessary to increase some default parameters. see static function TFormula::SetMaxima

WHY TFormula CANNOT ACCEPT A CLASS MEMBER FUNCTION ?

This is a frequently asked question. C++ is a strongly typed language. There is no way for TFormula (without recompiling this class) to know about all possible user defined data types. This also apply to the case of a static class function. Because TMath is a special and frequent case, TFormula is aware of all TMath functions.

Definition at line 71 of file TFormula.h.

Public Types

enum  { kNotGlobal = BIT(10), kNormalized = BIT(14), kLinear = BIT(16) }
 
- 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 ()
 Formula default constructor. More...
 
 TFormula (const char *name, const char *formula)
 Normal Formula constructor. More...
 
 TFormula (const TFormula &formula)
 Default constructor. More...
 
virtual ~TFormula ()
 Formula default destructor. More...
 
virtual void Analyze (const char *schain, Int_t &err, Int_t offset=0)
 Analyze a sub-expression in one formula. More...
 
virtual Bool_t AnalyzeFunction (TString &chaine, Int_t &err, Int_t offset=0)
 Check if the chain as function call. More...
 
virtual void Clear (Option_t *option="")
 Resets the objects. More...
 
virtual Int_t Compile (const char *expression="")
 Compile expression already stored in fTitle. More...
 
virtual void Copy (TObject &formula) const
 Copy this formula. More...
 
virtual char * DefinedString (Int_t code)
 Return address of string corresponding to special code. More...
 
virtual Double_t DefinedValue (Int_t code)
 Return value corresponding to special code. More...
 
virtual Int_t DefinedVariable (TString &variable, Int_t &action)
 Check if expression is in the list of defined variables. More...
 
virtual Double_t Eval (Double_t x, Double_t y=0, Double_t z=0, Double_t t=0) const
 Evaluate this formula. More...
 
virtual Double_t EvalPar (const Double_t *x, const Double_t *params=0)
 
virtual Double_t EvalParOld (const Double_t *x, const Double_t *params=0)
 Evaluate this formula. More...
 
virtual TString GetExpFormula (Option_t *option="") const
 Reconstruct the formula expression from the internal TFormula member variables. More...
 
virtual const TObjectGetLinearPart (Int_t i)
 Return linear part. More...
 
virtual Int_t GetNdim () const
 
virtual Int_t GetNpar () const
 
virtual Int_t GetNumber () const
 
Double_t GetParameter (Int_t ipar) const
 Return value of parameter number ipar. More...
 
Double_t GetParameter (const char *name) const
 Return value of parameter named parName. More...
 
virtual Double_tGetParameters () const
 
virtual void GetParameters (Double_t *params)
 
virtual const char * GetParName (Int_t ipar) const
 Return name of one parameter. More...
 
virtual Int_t GetParNumber (const char *name) const
 Return parameter number by name. More...
 
virtual Bool_t IsLinear () const
 
virtual Bool_t IsNormalized () const
 
TFormulaoperator= (const TFormula &rhs)
 Operator =. More...
 
void Optimize ()
 MI include. More...
 
virtual void Print (Option_t *option="") const
 Dump this formula with its attributes. More...
 
virtual void ProcessLinear (TString &replaceformula)
 If the formula is for linear fitting, change the title to normal and fill the LinearParts array. More...
 
virtual void SetNumber (Int_t number)
 
virtual void SetParameter (const char *name, Double_t parvalue)
 Initialize parameter number ipar. More...
 
virtual void SetParameter (Int_t ipar, Double_t parvalue)
 Initialize parameter number ipar. More...
 
virtual void SetParameters (const Double_t *params)
 Initialize array of all parameters. More...
 
virtual 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)
 Initialize up to 11 parameters All arguments except THE FIRST TWO are optional In case of a function with only one parameter, call this function with p1=0. More...
 
virtual void SetParName (Int_t ipar, const char *name)
 Set name of parameter number ipar. More...
 
virtual 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")
 Set up to 11 parameter names. More...
 
void Streamer (TBuffer &b, const TClass *onfile_class)
 Stream a class object. More...
 
void Streamer (TBuffer &b, Int_t version, UInt_t start, UInt_t count, const TClass *onfile_class=0)
 specialized streamer function being able to read old TF1 versions as TF1Old in memory More...
 
virtual void Update ()
 
- 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 SetName (const char *name)
 Set the name of the TNamed. 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...
 
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...
 
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 pad. 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...
 

Static Public Member Functions

static void GetMaxima (Int_t &maxop, Int_t &maxpar, Int_t &maxconst)
 static function to get the maximum value of 3 parameters -maxop : maximum number of operations -maxpar : maximum number of parameters -maxconst : maximum number of constants More...
 
static void SetMaxima (Int_t maxop=1000, Int_t maxpar=1000, Int_t maxconst=1000)
 static function to set the maximum value of 3 parameters More...
 
- 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 Types

enum  {
  kEnd = 0, kAdd = 1, kSubstract = 2, kMultiply = 3,
  kDivide = 4, kModulo = 5, kcos = 10, ksin = 11,
  ktan = 12, kacos = 13, kasin = 14, katan = 15,
  katan2 = 16, kfmod = 17, kpow = 20, ksq = 21,
  ksqrt = 22, kstrstr = 23, kmin = 24, kmax = 25,
  klog = 30, kexp = 31, klog10 = 32, kpi = 40,
  kabs = 41, ksign = 42, kint = 43, kSignInv = 44,
  krndm = 50, kAnd = 60, kOr = 61, kEqual = 62,
  kNotEqual = 63, kLess = 64, kGreater = 65, kLessThan = 66,
  kGreaterThan = 67, kNot = 68, kcosh = 70, ksinh = 71,
  ktanh = 72, kacosh = 73, kasinh = 74, katanh = 75,
  kStringEqual = 76, kStringNotEqual = 77, kBitAnd = 78, kBitOr = 79,
  kLeftShift = 80, kRightShift = 81, kJumpIf = 82, kJump = 83,
  kexpo = 100, kxexpo = 100, kyexpo = 101, kzexpo = 102,
  kxyexpo = 105, kgaus = 110, kxgaus = 110, kygaus = 111,
  kzgaus = 112, kxygaus = 115, klandau = 120, kxlandau = 120,
  kylandau = 121, kzlandau = 122, kxylandau = 125, kpol = 130,
  kxpol = 130, kypol = 131, kzpol = 132, kParameter = 140,
  kConstant = 141, kBoolOptimize = 142, kStringConst = 143, kVariable = 144,
  kFunctionCall = 145, kData = 146, kUnary = 147, kBinary = 148,
  kThree = 149, kDefinedVariable = 150, kDefinedString = 151, kPlusD = 152,
  kPlusDD = 153, kMultD = 154, kMultDD = 155, kBoolOptimizeOr = 156,
  kBoolOptimizeAnd = 157, kBoolSet = 158, kFDM = 159, kFD0 = 160,
  kFD1 = 161, kFD2 = 162, kFD3 = 163
}
 
typedef Double_t(TObject::* TFuncG) (const Double_t *, const Double_t *) const
 

Protected Member Functions

virtual Bool_t CheckOperands (Int_t operation, Int_t &err)
 Check whether the operand at 'oper-1' is compatible with the operation at 'oper'. More...
 
virtual Bool_t CheckOperands (Int_t leftoperand, Int_t rightoperartion, Int_t &err)
 Check whether the operands at 'leftoper' and 'oper-1' are compatible with the operation at 'oper'. More...
 
void ClearFormula (Option_t *option="")
 Resets the objects. More...
 
virtual void Convert (UInt_t fromVersion)
 
Double_t EvalParFast (const Double_t *x, const Double_t *params)
 Evaluate this formula. More...
 
Double_t EvalPrimitive (const Double_t *x, const Double_t *params)
 Evaluate primitive formula. More...
 
Double_t EvalPrimitive0 (const Double_t *x, const Double_t *params)
 Evaluate primitive formula. More...
 
Double_t EvalPrimitive1 (const Double_t *x, const Double_t *params)
 Evaluate primitive formula. More...
 
Double_t EvalPrimitive2 (const Double_t *x, const Double_t *params)
 Evaluate primitive formula. More...
 
Double_t EvalPrimitive3 (const Double_t *x, const Double_t *params)
 Evaluate primitive formula. More...
 
Double_t EvalPrimitive4 (const Double_t *x, const Double_t *params)
 Evaluate primitive formula. More...
 
Short_t GetAction (Int_t code) const
 
Short_t GetActionOptimized (Int_t code) const
 
Int_t GetActionParam (Int_t code) const
 
Int_t GetActionParamOptimized (Int_t code) const
 
Int_tGetOper () const
 
Int_tGetOperOptimized () const
 
virtual Bool_t IsString (Int_t oper) const
 Return true if the expression at the index 'oper' has to be treated as a string. More...
 
void MakePrimitive (const char *expr, Int_t pos)
 MakePrimitive find TFormulaPrimitive replacement for some operands. More...
 
Int_t PreCompile ()
 pointer to optimal function More...
 
void SetAction (Int_t code, Int_t value, Int_t param=0)
 
void SetActionOptimized (Int_t code, Int_t value, Int_t param=0)
 
virtual Bool_t StringToNumber (Int_t code)
 Try to 'demote' a string into an array bytes. 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 ()
 

Protected Attributes

TBits fAlreadyFound
 
Double_tfConst
 
TStringfExpr
 
TStringfExprOptimized
 Number of operators after optimization. More...
 
TObjArray fFunctions
 
TObjArray fLinearParts
 
TStringfNames
 
Int_t fNconst
 
Int_t fNdim
 
Int_t fNoper
 
Int_t fNOperOptimized
 cache for information More...
 
Int_t fNpar
 
Int_t fNstring
 
Int_t fNumber
 
Int_t fNval
 
TOperOffsetfOperOffset
 [fNOperOptimized] List of operators. (See documentation for changes made at version 7) More...
 
Int_tfOperOptimized
 [fNOperOptimized] List of expressions More...
 
TFuncG fOptimal
 [fNPar] predefined function More...
 
Double_tfParams
 
TFormulaPrimitive ** fPredefined
 [fNOperOptimized] Offsets of operrands More...
 
- Protected Attributes inherited from TNamed
TString fName
 
TString fTitle
 

Private Attributes

Int_tfOper
 

#include "inc/v5/TFormula.h"

Inheritance diagram for ROOT::v5::TFormula:
[legend]

Member Typedef Documentation

typedef Double_t(TObject::* ROOT::v5::TFormula::TFuncG) (const Double_t *, const Double_t *) const
protected

Definition at line 75 of file TFormula.h.

Member Enumeration Documentation

anonymous enum
Enumerator
kNotGlobal 
kNormalized 
kLinear 

Definition at line 217 of file TFormula.h.

anonymous enum
protected
Enumerator
kEnd 
kAdd 
kSubstract 
kMultiply 
kDivide 
kModulo 
kcos 
ksin 
ktan 
kacos 
kasin 
katan 
katan2 
kfmod 
kpow 
ksq 
ksqrt 
kstrstr 
kmin 
kmax 
klog 
kexp 
klog10 
kpi 
kabs 
ksign 
kint 
kSignInv 
krndm 
kAnd 
kOr 
kEqual 
kNotEqual 
kLess 
kGreater 
kLessThan 
kGreaterThan 
kNot 
kcosh 
ksinh 
ktanh 
kacosh 
kasinh 
katanh 
kStringEqual 
kStringNotEqual 
kBitAnd 
kBitOr 
kLeftShift 
kRightShift 
kJumpIf 
kJump 
kexpo 
kxexpo 
kyexpo 
kzexpo 
kxyexpo 
kgaus 
kxgaus 
kygaus 
kzgaus 
kxygaus 
klandau 
kxlandau 
kylandau 
kzlandau 
kxylandau 
kpol 
kxpol 
kypol 
kzpol 
kParameter 
kConstant 
kBoolOptimize 
kStringConst 
kVariable 
kFunctionCall 
kData 
kUnary 
kBinary 
kThree 
kDefinedVariable 
kDefinedString 
kPlusD 
kPlusDD 
kMultD 
kMultDD 
kBoolOptimizeOr 
kBoolOptimizeAnd 
kBoolSet 
kFDM 
kFD0 
kFD1 
kFD2 
kFD3 

Definition at line 141 of file TFormula.h.

Constructor & Destructor Documentation

TFormula::TFormula ( )

Formula default constructor.

Definition at line 134 of file TFormula_v5.cxx.

TFormula::TFormula ( const char *  name,
const char *  formula 
)

Normal Formula constructor.

Definition at line 161 of file TFormula_v5.cxx.

TFormula::TFormula ( const TFormula formula)

Default constructor.

Definition at line 274 of file TFormula_v5.cxx.

TFormula::~TFormula ( )
virtual

Formula default destructor.

Definition at line 311 of file TFormula_v5.cxx.

Member Function Documentation

void TFormula::Analyze ( const char *  schain,
Int_t err,
Int_t  offset = 0 
)
virtual

Analyze a sub-expression in one formula.

Expressions in one formula are recursively analyzed. Result of analysis is stored in the object tables.

Table of function codes and errors

* functions :
+ 1 pow 20
- 2 sq 21
* 3 sqrt 22
/ 4 strstr 23
% 5 min 24
max 25
log 30
cos 10 exp 31
sin 11 log10 32
tan 12
acos 13 abs 41
asin 14 sign 42
atan 15 int 43
atan2 16
fmod 17 rndm 50
cosh 70 acosh 73
sinh 71 asinh 74
tanh 72 atanh 75
expo 100 gaus 110 gausn (see note below)
expo(0) 100 0 gaus(0) 110 0 gausn(0)
expo(1) 100 1 gaus(1) 110 1 gausn(1)
xexpo 100 x xgaus 110 x xgausn
yexpo 101 x ygaus 111 x ygausn
zexpo 102 x zgaus 112 x zgausn
xyexpo 105 x xygaus 115 x xygausn
yexpo(5) 102 5 ygaus(5) 111 5 ygausn(5)
xyexpo(2) 105 2 xygaus(2) 115 2 xygausn(2)
landau 120 x landaun (see note below)
landau(0) 120 0 landaun(0)
landau(1) 120 1 landaun(1)
xlandau 120 x xlandaun
ylandau 121 x ylandaun
zlandau 122 x zlandaun
xylandau 125 x xylandaun
ylandau(5) 121 5 ylandaun(5)
xylandau(2) 125 2 xylandaun(2)
pol0 130 x pol1 130 1xx
pol0(0) 130 0 pol1(0) 130 100
pol0(1) 130 1 pol1(1) 130 101
xpol0 130 x xpol1 130 101
ypol0 131 x ypol1 131 101
zpol0 132 x zpol1 132 1xx
ypol0(5) 131 5 ypol1(5) 131 105
pi 40
&& 60 < 64
|| 61 > 65
== 62 <= 66
!= 63 => 67
! 68
==(string) 76 & 78
!=(string) 77 | 79
<<(shift) 80 >>(shift) 81
? : 82
* constants (kConstants) :
c0 141 1 c1 141 2 etc..
* strings (kStringConst):
sX 143 x
* variables (kFormulaVar) :
x 144 0 y 144 1 z 144 2 t 144 3
* parameters :
[1] 140 1
[2] 140 2
etc.

Special cases for normalized gaussian or landau distributions

the expression "gaus" is a substitute for

[0]*exp(-0.5*((x-[1])/[2])**2)

to obtain a standard normalized gaussian, use "gausn" instead of "gaus" the expression "gausn" is a substitute for

[0]*exp(-0.5*((x-[1])/[2])**2)/(sqrt(2*pi)*[2]))

WARNING: gaus and gausn are mutually exclusive in the same expression.

In the same way the expression "landau" is a substitute for

[0]*TMath::Landau(x,[1],[2],kFALSE)

to obtain a standard normalized landau, use "landaun" instead of "landau" the expression "landaun" is a substitute for

[0]*TMath::Landau(x,[1],[2],kTRUE)

WARNING: landau and landaun are mutually exclusive in the same expression.

Boolean optimization (kBoolOptmize) :

Those pseudo operation are used to implement lazy evaluation of && and ||. When the left hand of the expression if false (respectively true), the evaluation of the right is entirely skipped (since it would not change the value of the expression).

&& 142 11 (one operation on right) 142 21 (2 operations on right) || 142 12 (one operation on right) 142 22 (2 operations on right)

  • functions calls (kFunctionCall) :

    f0 145 0 f1 145 1 etc..

Errors :

1   : Division By Zero
2   : Invalid Floating Point Operation
4   : Empty String
5   : invalid syntax
6   : Too many operators
7   : Too many parameters
10  : z specified but not x and y
11  : z and y specified but not x
12  : y specified but not x
13  : z and x specified but not y
20  : non integer value for parameter number
21  : atan2 requires two arguments
22  : pow requires two arguments
23  : degree of polynomial not specified
24  : Degree of polynomial must be positive
25  : Degree of polynomial must be less than 20
26  : Unknown name
27  : Too many constants in expression
28  : strstr requires two arguments
29  : interpreted or compiled function have to return a numerical type
30  : Bad numerical expression
31  : Part of the variable exist but some of it is not accessible or useable
40  : '(' is expected
41  : ')' is expected
42  : '[' is expected
43  : ']' is expected
TFormula_analyze.png

Special functions

By default, the formula is assigned fNumber=0. However, the following formula built with simple functions are assigned fNumber:

 "gaus"      100  (or gausn)
 "xygaus"    110
 "expo"      200
 "polN"      300+N
 "landau"    400
 "xylandau"  410

Note that expressions like gaus(0), expo(1) will force fNumber=0

Warning when deriving a class from TFormula

If you overload this member function, you also HAVE TO never call the constructor:

TFormula::TFormula(const char *name,const char *expression)

and write your own constructor

MyClass::MyClass(const char *name,const char *expression) : TFormula()

which has to call the TFormula default constructor and whose implementation should be similar to the implementation of the normal TFormula constructor

This is necessary because the normal TFormula constructor call indirectly the virtual member functions Analyze, DefaultString, DefaultValue and DefaultVariable.

Definition at line 710 of file TFormula_v5.cxx.

Bool_t TFormula::AnalyzeFunction ( TString chaine,
Int_t err,
Int_t  offset = 0 
)
virtual

Check if the chain as function call.

If you overload this member function, you also HAVE TO never call the constructor:

TFormula::TFormula(const char *name,const char *expression)

and write your own constructor

MyClass::MyClass(const char *name,const char *expression) : TFormula()

which has to call the TFormula default constructor and whose implementation should be similar to the implementation of the normal TFormula constructor

This is necessary because the normal TFormula constructor call indirectly the virtual member functions Analyze, DefaultString, DefaultValue and DefaultVariable.

Definition at line 344 of file TFormula_v5.cxx.

Bool_t TFormula::CheckOperands ( Int_t  oper,
Int_t err 
)
protectedvirtual

Check whether the operand at 'oper-1' is compatible with the operation at 'oper'.

Definition at line 2165 of file TFormula_v5.cxx.

Bool_t TFormula::CheckOperands ( Int_t  leftoper,
Int_t  oper,
Int_t err 
)
protectedvirtual

Check whether the operands at 'leftoper' and 'oper-1' are compatible with the operation at 'oper'.

Definition at line 2179 of file TFormula_v5.cxx.

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

Resets the objects.

Resets the object to its state before compilation.

Reimplemented from TNamed.

Definition at line 2210 of file TFormula_v5.cxx.

void TFormula::ClearFormula ( Option_t option = "")
protected

Resets the objects.

Resets the object to its state before compilation.

Definition at line 2220 of file TFormula_v5.cxx.

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

Compile expression already stored in fTitle.

Loop on all subexpressions of formula stored in fTitle

If you overload this member function, you also HAVE TO never call the constructor:

TFormula::TFormula(const char *name,const char *expression)

and write your own constructor

MyClass::MyClass(const char *name,const char *expression) : TFormula()

which has to call the TFormula default constructor and whose implementation should be similar to the implementation of the normal TFormula constructor

This is necessary because the normal TFormula constructor call indirectly the virtual member functions Analyze, DefaultString, DefaultValue and DefaultVariable.

TFormula_compile.png

Definition at line 2289 of file TFormula_v5.cxx.

void TFormula::Convert ( UInt_t  fromVersion)
protectedvirtual

Reimplemented in TTreeFormula.

Definition at line 3561 of file TFormula_v5.cxx.

void TFormula::Copy ( TObject formula) const
virtual

Copy this formula.

Reimplemented from TNamed.

Definition at line 2458 of file TFormula_v5.cxx.

char * TFormula::DefinedString ( Int_t  code)
virtual

Return address of string corresponding to special code.

This member function is inactive in the TFormula class. It may be redefined in derived classes.

If you overload this member function, you also HAVE TO never call the constructor:

TFormula::TFormula(const char *name,const char *expression)

and write your own constructor

MyClass::MyClass(const char *name,const char *expression) : TFormula()

which has to call the TFormula default constructor and whose implementation should be similar to the implementation of the normal TFormula constructor

This is necessary because the normal TFormula constructor call indirectly the virtual member functions Analyze, DefaultString, DefaultValue and DefaultVariable.

Definition at line 2552 of file TFormula_v5.cxx.

Double_t TFormula::DefinedValue ( Int_t  code)
virtual

Return value corresponding to special code.

This member function is inactive in the TFormula class. It may be redefined in derived classes.

If you overload this member function, you also HAVE TO never call the constructor:

TFormula::TFormula(const char *name,const char *expression)

and write your own constructor

MyClass::MyClass(const char *name,const char *expression) : TFormula()

which has to call the TFormula default constructor and whose implementation should be similar to the implementation of the normal TFormula constructor

This is necessary because the normal TFormula constructor call indirectly the virtual member functions Analyze, DefaultString, DefaultValue and DefaultVariable.

Reimplemented in RooFormula.

Definition at line 2583 of file TFormula_v5.cxx.

Int_t TFormula::DefinedVariable ( TString chaine,
Int_t action 
)
virtual

Check if expression is in the list of defined variables.

This member function can be overloaded in derived classes

If you overload this member function, you also HAVE TO never call the constructor:

TFormula::TFormula(const char *name,const char *expression)

and write your own constructor

MyClass::MyClass(const char *name,const char *expression) : TFormula()

which has to call the TFormula default constructor and whose implementation should be similar to the implementation of the normal TFormula constructor

This is necessary because the normal TFormula constructor call indirectly the virtual member functions Analyze, DefaultString, DefaultValue and DefaultVariable.

The expected returns values are

  • -2 : the name has been recognized but won't be usable
  • -1 : the name has not been recognized
  • >=0 : the name has been recognized, return the action parameter.

Reimplemented in TTreeFormula, and RooFormula.

Definition at line 2618 of file TFormula_v5.cxx.

Double_t TFormula::Eval ( Double_t  x,
Double_t  y = 0,
Double_t  z = 0,
Double_t  t = 0 
) const
virtual

Evaluate this formula.

The current value of variables x,y,z,t is passed through x, y, z and t. The parameters used will be the ones in the array params if params is given otherwise parameters will be taken from the stored data members fParams

Definition at line 2665 of file TFormula_v5.cxx.

virtual Double_t ROOT::v5::TFormula::EvalPar ( const Double_t x,
const Double_t params = 0 
)
inlinevirtual

Definition at line 241 of file TFormula.h.

Double_t TFormula::EvalParFast ( const Double_t x,
const Double_t uparams 
)
protected

Evaluate this formula.

The current value of variables x,y,z,t is passed through the pointer x. The parameters used will be the ones in the array params if params is given otherwise parameters will be taken from the stored data members fParams

TFormula_eval.png

Definition at line 4186 of file TFormula_v5.cxx.

Double_t TFormula::EvalParOld ( const Double_t x,
const Double_t uparams = 0 
)
virtual

Evaluate this formula.

The current value of variables x,y,z,t is passed through the pointer x. The parameters used will be the ones in the array params if params is given otherwise parameters will be taken from the stored data members fParams

TFormula_eval.png

Definition at line 2684 of file TFormula_v5.cxx.

Double_t TFormula::EvalPrimitive ( const Double_t x,
const Double_t params 
)
protected

Evaluate primitive formula.

Definition at line 4111 of file TFormula_v5.cxx.

Double_t TFormula::EvalPrimitive0 ( const Double_t x,
const Double_t params 
)
protected

Evaluate primitive formula.

Definition at line 4132 of file TFormula_v5.cxx.

Double_t TFormula::EvalPrimitive1 ( const Double_t x,
const Double_t params 
)
protected

Evaluate primitive formula.

Definition at line 4141 of file TFormula_v5.cxx.

Double_t TFormula::EvalPrimitive2 ( const Double_t x,
const Double_t params 
)
protected

Evaluate primitive formula.

Definition at line 4150 of file TFormula_v5.cxx.

Double_t TFormula::EvalPrimitive3 ( const Double_t x,
const Double_t params 
)
protected

Evaluate primitive formula.

Definition at line 4160 of file TFormula_v5.cxx.

Double_t TFormula::EvalPrimitive4 ( const Double_t x,
const Double_t params 
)
protected

Evaluate primitive formula.

Definition at line 4170 of file TFormula_v5.cxx.

Short_t ROOT::v5::TFormula::GetAction ( Int_t  code) const
inlineprotected

Definition at line 110 of file TFormula.h.

Short_t ROOT::v5::TFormula::GetActionOptimized ( Int_t  code) const
inlineprotected

Definition at line 118 of file TFormula.h.

Int_t ROOT::v5::TFormula::GetActionParam ( Int_t  code) const
inlineprotected

Definition at line 111 of file TFormula.h.

Int_t ROOT::v5::TFormula::GetActionParamOptimized ( Int_t  code) const
inlineprotected

Definition at line 119 of file TFormula.h.

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

Reconstruct the formula expression from the internal TFormula member variables.

This function uses the internal member variables of TFormula to construct the mathematical expression associated with the TFormula instance. This function can be used to get an expanded version of the expression originally assigned to the TFormula instance, i.e. that the string returned by GetExpFormula() doesn't depend on other TFormula object names.

if option contains "p" the returned string will contain the formula expression with symbolic parameters, eg [0] replaced by the actual value of the parameter. Example: if expression in formula is: "[0]*(x>-[1])+[2]*exp(-[3]*x)" and parameters are 3.25,-4.01,4.44,-0.04, GetExpFormula("p") will return: "(3.25*(x>+4.01))+(4.44*exp(+0.04*x))"

Definition at line 3019 of file TFormula_v5.cxx.

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

Return linear part.

Definition at line 3209 of file TFormula_v5.cxx.

void TFormula::GetMaxima ( Int_t maxop,
Int_t maxpar,
Int_t maxconst 
)
static

static function to get the maximum value of 3 parameters -maxop : maximum number of operations -maxpar : maximum number of parameters -maxconst : maximum number of constants

Definition at line 4537 of file TFormula_v5.cxx.

virtual Int_t ROOT::v5::TFormula::GetNdim ( ) const
inlinevirtual

Definition at line 243 of file TFormula.h.

virtual Int_t ROOT::v5::TFormula::GetNpar ( void  ) const
inlinevirtual

Definition at line 244 of file TFormula.h.

virtual Int_t ROOT::v5::TFormula::GetNumber ( ) const
inlinevirtual

Definition at line 245 of file TFormula.h.

Int_t* ROOT::v5::TFormula::GetOper ( ) const
inlineprotected

Definition at line 109 of file TFormula.h.

Int_t* ROOT::v5::TFormula::GetOperOptimized ( ) const
inlineprotected

Definition at line 117 of file TFormula.h.

Double_t TFormula::GetParameter ( Int_t  ipar) const

Return value of parameter number ipar.

Definition at line 3219 of file TFormula_v5.cxx.

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

Return value of parameter named parName.

Definition at line 3228 of file TFormula_v5.cxx.

virtual Double_t* ROOT::v5::TFormula::GetParameters ( ) const
inlinevirtual

Definition at line 249 of file TFormula.h.

virtual void ROOT::v5::TFormula::GetParameters ( Double_t params)
inlinevirtual

Definition at line 250 of file TFormula.h.

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

Return name of one parameter.

Definition at line 3242 of file TFormula_v5.cxx.

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

Return parameter number by name.

Definition at line 3252 of file TFormula_v5.cxx.

virtual Bool_t ROOT::v5::TFormula::IsLinear ( ) const
inlinevirtual

Definition at line 253 of file TFormula.h.

virtual Bool_t ROOT::v5::TFormula::IsNormalized ( ) const
inlinevirtual

Definition at line 254 of file TFormula.h.

Bool_t TFormula::IsString ( Int_t  oper) const
protectedvirtual

Return true if the expression at the index 'oper' has to be treated as a string.

Reimplemented in TTreeFormula.

Definition at line 3266 of file TFormula_v5.cxx.

void TFormula::MakePrimitive ( const char *  expr,
Int_t  pos 
)
protected

MakePrimitive find TFormulaPrimitive replacement for some operands.

Definition at line 3743 of file TFormula_v5.cxx.

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

Operator =.

Definition at line 300 of file TFormula_v5.cxx.

void TFormula::Optimize ( )

MI include.

Optimize formula

Definition at line 3815 of file TFormula_v5.cxx.

Int_t TFormula::PreCompile ( )
protected

pointer to optimal function

Pre compile function.

Definition at line 4478 of file TFormula_v5.cxx.

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

Dump this formula with its attributes.

Reimplemented from TNamed.

Reimplemented in RooFormula.

Definition at line 3274 of file TFormula_v5.cxx.

void TFormula::ProcessLinear ( TString replaceformula)
virtual

If the formula is for linear fitting, change the title to normal and fill the LinearParts array.

Definition at line 3303 of file TFormula_v5.cxx.

void ROOT::v5::TFormula::SetAction ( Int_t  code,
Int_t  value,
Int_t  param = 0 
)
inlineprotected

Definition at line 113 of file TFormula.h.

void ROOT::v5::TFormula::SetActionOptimized ( Int_t  code,
Int_t  value,
Int_t  param = 0 
)
inlineprotected

Definition at line 121 of file TFormula.h.

void TFormula::SetMaxima ( Int_t  maxop = 1000,
Int_t  maxpar = 1000,
Int_t  maxconst = 1000 
)
static

static function to set the maximum value of 3 parameters

  • maxop : maximum number of operations
  • maxpar : maximum number of parameters
  • maxconst : maximum number of constants

None of these parameters cannot be less than 10 (default is 1000) call this function to increase one or all maxima when processing very complex formula, eg TFormula::SetMaxima(100000,1000,1000000); If you process many functions with a small number of operations/parameters you may gain some memory and performance by decreasing these values.

Definition at line 4524 of file TFormula_v5.cxx.

virtual void ROOT::v5::TFormula::SetNumber ( Int_t  number)
inlinevirtual

Definition at line 257 of file TFormula.h.

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

Initialize parameter number ipar.

Definition at line 3372 of file TFormula_v5.cxx.

void TFormula::SetParameter ( Int_t  ipar,
Double_t  parvalue 
)
virtual

Initialize parameter number ipar.

Definition at line 3383 of file TFormula_v5.cxx.

void TFormula::SetParameters ( const Double_t params)
virtual

Initialize array of all parameters.

See also the next function with the same name.

Definition at line 3394 of file TFormula_v5.cxx.

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 
)
virtual

Initialize up to 11 parameters All arguments except THE FIRST TWO are optional In case of a function with only one parameter, call this function with p1=0.

Minimum two arguments are required to differentiate this function from the SetParameters(cont Double_t *params)

Definition at line 3409 of file TFormula_v5.cxx.

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

Set name of parameter number ipar.

Definition at line 3429 of file TFormula_v5.cxx.

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" 
)
virtual

Set up to 11 parameter names.

Definition at line 3438 of file TFormula_v5.cxx.

void TFormula::Streamer ( TBuffer b,
const TClass onfile_class 
)

Stream a class object.

Definition at line 3457 of file TFormula_v5.cxx.

void TFormula::Streamer ( TBuffer b,
Int_t  version,
UInt_t  start,
UInt_t  count,
const TClass onfile_class = 0 
)

specialized streamer function being able to read old TF1 versions as TF1Old in memory

Definition at line 3495 of file TFormula_v5.cxx.

Bool_t TFormula::StringToNumber ( Int_t  code)
protectedvirtual

Try to 'demote' a string into an array bytes.

If this is not possible, return false.

Reimplemented in TTreeFormula.

Definition at line 2199 of file TFormula_v5.cxx.

virtual void ROOT::v5::TFormula::Update ( )
inlinevirtual

Definition at line 269 of file TFormula.h.

Member Data Documentation

TBits ROOT::v5::TFormula::fAlreadyFound
protected

Definition at line 94 of file TFormula.h.

Double_t* ROOT::v5::TFormula::fConst
protected

Definition at line 88 of file TFormula.h.

TString* ROOT::v5::TFormula::fExpr
protected

Definition at line 84 of file TFormula.h.

TString* ROOT::v5::TFormula::fExprOptimized
protected

Number of operators after optimization.

Definition at line 98 of file TFormula.h.

TObjArray ROOT::v5::TFormula::fFunctions
protected

Definition at line 91 of file TFormula.h.

TObjArray ROOT::v5::TFormula::fLinearParts
protected

Definition at line 92 of file TFormula.h.

TString* ROOT::v5::TFormula::fNames
protected

Definition at line 90 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNconst
protected

Definition at line 80 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNdim
protected

Definition at line 77 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNoper
protected

Definition at line 79 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNOperOptimized
protected

cache for information

Definition at line 97 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNpar
protected

Definition at line 78 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNstring
protected

Definition at line 83 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNumber
protected

Definition at line 81 of file TFormula.h.

Int_t ROOT::v5::TFormula::fNval
protected

Definition at line 82 of file TFormula.h.

Int_t* ROOT::v5::TFormula::fOper
private

Definition at line 86 of file TFormula.h.

TOperOffset* ROOT::v5::TFormula::fOperOffset
protected

[fNOperOptimized] List of operators. (See documentation for changes made at version 7)

Definition at line 100 of file TFormula.h.

Int_t* ROOT::v5::TFormula::fOperOptimized
protected

[fNOperOptimized] List of expressions

Definition at line 99 of file TFormula.h.

TFuncG ROOT::v5::TFormula::fOptimal
protected

[fNPar] predefined function

Definition at line 102 of file TFormula.h.

Double_t* ROOT::v5::TFormula::fParams
protected

Definition at line 89 of file TFormula.h.

TFormulaPrimitive** ROOT::v5::TFormula::fPredefined
protected

[fNOperOptimized] Offsets of operrands

Definition at line 101 of file TFormula.h.


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