#ifndef TGO4FITDEPENDENCY_H
#define TGO4FITDEPENDENCY_H

#include "TObject.h"
#include "TString.h"

class TFormula;

/**
 * Object, used to store dependency of one parameter from other, calculated via expression.
 * It used in dependencies calculations, in parameters initialization and in resuly calculation.
 * Value can be calculated via expression or be just a double constant.
 * The result parameter is sets via it's index in fitter parameters list.
 */
class TGo4FitDependency : public TObject {
   public:
      TGo4FitDependency();
      TGo4FitDependency(const char* iParameter, const char* iExpression);
      TGo4FitDependency(const char* iParameter, Double_t InitValue);
      virtual ~TGo4FitDependency();

      void SetParameter(const char* iParameter);
      void SetInitValue(Double_t InitValue);
      void SetExpression(const char* iExpression);

      const TString& GetParameter() { return fxParameter; }
      const TString& GetExpression() { return fxExpression; }
      Double_t GetInitValue() { return fdInitValue; }

      Bool_t IsResultDepend() { return fxParameter.Length()==0; }
      Bool_t IsInitValue() { return fxExpression.Length()==0; }

      void Initialize(Int_t iNumPar, const char* iFormula);
      Double_t ExecuteDependency(Double_t* Params);
      void Finalize();

      virtual void Print(Option_t* option) const;

   protected:
      TString fxParameter;
      TString fxExpression;
      Double_t fdInitValue;
      Int_t fiNumPar;                  //!
      TFormula *fxFormula;             //!

   ClassDef(TGo4FitDependency,1)
};
#endif // TGO4FITDEPENDENCY_H