class TFormulaPrimitive: public TNamed

 The Formula Primitive class

    Helper class for TFormula to speed up TFormula evaluation
    TFormula can use all functions registered in the list of TFormulaPrimitives
    User can add new function to the list of primitives
    if FormulaPrimitive with given name is already defined new primitive is ignored
    Example:
      TFormulaPrimitive::AddFormula(new TFormulaPrimitive("Pow2","Pow2",TFastFun::Pow2));
      TF1 f1("f1","Pow2(x)");



    TFormulaPrimitive is used to get direct acces to the function pointers
    GenFunc     -  pointers  to the static function
    TFunc       -  pointers  to the data member functions

    The following sufixes are currently used, to describe function arguments:

    G     - generic layout - pointer to double (arguments), pointer to double (parameters)
    10    - double
    110   - double, double
    1110  - double, double, double