TLinearFitter

class TLinearFitter : public TVirtualFitter

    private:

      void AddToDesign(Double_t* x, Double_t y, Double_t e)
      void Graph2DLinearFitter()
      void GraphLinearFitter()
      void HistLinearFitter()
      void MultiGraphLinearFitter()

    public:

                        TLinearFitter()
                        TLinearFitter(Int_t ndim, const char* formula, Option_t* opt = "D")
                        TLinearFitter(Int_t ndim)
                        TLinearFitter(TFormula* function, Option_t* opt = "D")
                virtual ~TLinearFitter()
           virtual void AddPoint(Double_t* x, Double_t y, Double_t e = 1)
           virtual void AssignData(Int_t npoints, Int_t xncols, Double_t* x, Double_t* y, Double_t* e = 0)
           virtual void Chisquare()
       virtual Double_t Chisquare(Int_t, Double_t*) const
         static TClass* Class()
           virtual void Clear(Option_t* option)
           virtual void ClearPoints()
           virtual void Eval()
          virtual Int_t ExecuteCommand(const char* command, Double_t*, Int_t)
           virtual void FixParameter(Int_t ipar)
           virtual void FixParameter(Int_t ipar, Double_t parvalue)
       virtual Double_t GetChisquare()
      virtual Double_t* GetCovarianceMatrix() const
           virtual void GetCovarianceMatrix(TMatrixD& matr)
       virtual Double_t GetCovarianceMatrixElement(Int_t i, Int_t j) const
           virtual void GetErrors(TVectorD& vpar)
          virtual Int_t GetErrors(Int_t, Double_t&, Double_t&, Double_t&, Double_t&) const
          virtual Int_t GetNumberFreeParameters() const
          virtual Int_t GetNumberTotalParameters() const
       virtual Double_t GetParameter(Int_t ipar) const
          virtual Int_t GetParameter(Int_t, char*, Double_t&, Double_t&, Double_t&, Double_t&) const
           virtual void GetParameters(TVectorD& vpar)
       virtual Double_t GetParError(Int_t ipar) const
       virtual Double_t GetParSignificance(Int_t ipar) const
       virtual Double_t GetParTValue(Int_t ipar) const
          virtual Int_t GetStats(Double_t&, Double_t&, Double_t&, Int_t&, Int_t&) const
       virtual Double_t GetSumLog(Int_t)
        virtual TClass* IsA() const
         virtual Bool_t IsFixed(Int_t ipar) const
           virtual void PrintResults(Int_t level, Double_t amin = 0) const
           virtual void ReleaseParameter(Int_t ipar)
           virtual void SetDim(Int_t n)
           virtual void SetFitMethod(const char*)
           virtual void SetFormula(const char* formula)
           virtual void SetFormula(TFormula* function)
          virtual Int_t SetParameter(Int_t, const char*, Double_t, Double_t, Double_t, Double_t)
           virtual void ShowMembers(TMemberInspector& insp, char* parent)
           virtual void StoreData(Bool_t store)
           virtual void Streamer(TBuffer& b)
                   void StreamerNVirtual(TBuffer& b)
         virtual Bool_t UpdateMatrix()

Data Members

    private:

         TVectorD fParams         vector of parameters
      TMatrixDSym fParCovar       matrix of parameters' covariances
         TVectorD fTValues        T-Values of parameters
         TVectorD fParSign        significance levels of parameters
      TMatrixDSym fDesign         matrix AtA
      TMatrixDSym fDesignTemp     ! temporary matrix, used for num.stability
      TMatrixDSym fDesignTemp2    !
      TMatrixDSym fDesignTemp3    !
         TVectorD fAtb            vector Atb
         TVectorD fAtbTemp        ! temporary vector, used for num.stability
         TVectorD fAtbTemp2       !
         TVectorD fAtbTemp3       !
          Bool_t* fFixedParams    array of fixed/released params
        TObjArray fFunctions      array of basis functions
         TVectorD fY              the values being fit
         Double_t fY2             sum of square of y, used for chisquare
         Double_t fY2Temp         ! temporary variable used for num.stability
         TMatrixD fX              values of x
         TVectorD fE              the errors if they are known
        TFormula* fInputFunction  the function being fit
            Int_t fNpoints        number of points
            Int_t fNfunctions     number of basis functions
            Int_t fFormulaSize    length of the formula
            Int_t fNdim           number of dimensions in the formula
            Int_t fNfixed         number of fixed parameters
            Int_t fSpecial        =100+n if fitting a polynomial of deg.n
            char* fFormula        the formula
           Bool_t fIsSet          Has the formula been set?
           Bool_t fStoreData      Is the data stored?
           Bool_t fCorrect        correcting for the case y>>e
         Double_t fChisquare      Chisquare of the fit

Class Description

default c-tor, input data is stored
If you don't want to store the input data,
run the function StoreData(kFALSE) after constructor

The parameter stands for number of dimensions in the fitting formula
The input data is stored. If you don't want to store the input data,
run the function StoreData(kFALSE) after constructor

First parameter stands for number of dimensions in the fitting formula
Second parameter is the fitting formula: see class description for formula syntax
Options:
The option is to store or not to store the data
If you don't want to store the data, choose "" for the option, or run
StoreData(kFalse) member function after the constructor

This constructor uses a linear function. How to create it?
TFormula now accepts formulas of the following kind:
TFormula("f", "x++y++z++x*x"). Other than the look, it's in no
way different from the regular formula, it can be evaluated,
drawn, etc.
The option is to store or not to store the data
If you don't want to store the data, choose "" for the option, or run
StoreData(kFalse) member function after the constructor

 Linear fitter cleanup.

Adds 1 point to the fitter.
First parameter stands for the coordinates of the point, where the function is measured
Second parameter - the value being fitted
Third parameter - weight(measurement error) of this point (=1 by default)

This function is to use when you already have all the data in arrays
and don't want to copy them into the fitter. In this function, the Use() method
of TVectorD and TMatrixD is used, so no bytes are physically moved around.
First parameter - number of points to fit
Second parameter - number of variables in the model
Third parameter - the variables of the model, stored in the following way:
(x0(0), x1(0), x2(0), x3(0), x0(1), x1(1), x2(1), x3(1),...

Add a point to the AtA matrix and to the Atb vector.

Clears everything. Used in TH1::Fit().

To be used when different sets of points are fitted with the same formula.

Calculates the chisquare.

 Evaluate the function.

Fixes paramter #ipar at its current value.

Fixes parameter #ipar at value parvalue.

Releases parameter #ipar.

 Get the Chisquare.

set the number of dimensions

Additive parts should be separated by "++".
Examples (ai are parameters to fit):
1.fitting function: a0*x0 + a1*x1 + a2*x2
  input formula "x0++x1++x2"
2.TMath functions can be used:
  fitting function: a0*TMath::Gaus(x0, 0, 1) + a1*x1
  input formula:    "TMath::Gaus(x0, 0, 1)++x1"
fills the array of functions

Set the fitting function.

To use in TGraph::Fit and TH1::Fit().

 Level = 3 (to be consistent with minuit)  prints parameters and parameter
 errors.

Used in TGraph::Fit().

 Minimization function for H1s using a Chisquare method.

Inline Functions

               void GetCovarianceMatrix(TMatrixD& matr)
           Double_t GetCovarianceMatrixElement(Int_t i, Int_t j) const
              Int_t GetNumberTotalParameters() const
              Int_t GetNumberFreeParameters() const
           Double_t GetParameter(Int_t ipar) const
           Double_t GetParTValue(Int_t ipar) const
           Double_t GetParSignificance(Int_t ipar) const
             Bool_t IsFixed(Int_t ipar) const
               void StoreData(Bool_t store)
           Double_t Chisquare(Int_t, Double_t*) const
              Int_t GetErrors(Int_t, Double_t&, Double_t&, Double_t&, Double_t&) const
              Int_t GetParameter(Int_t, char*, Double_t&, Double_t&, Double_t&, Double_t&) const
              Int_t GetStats(Double_t&, Double_t&, Double_t&, Int_t&, Int_t&) const
           Double_t GetSumLog(Int_t)
               void SetFitMethod(const char*)
              Int_t SetParameter(Int_t, const char*, Double_t, Double_t, Double_t, Double_t)
            TClass* Class()
            TClass* IsA() const
               void ShowMembers(TMemberInspector& insp, char* parent)
               void Streamer(TBuffer& b)
               void StreamerNVirtual(TBuffer& b)