ROOT   6.10/09 Reference Guide
VavilovAccuratePdf.h
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1 // @(#)root/mathmore:$Id$
2 // Authors: B. List 29.4.2010
3
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24
25 // Header file for class VavilovAccuratePdf
26 //
27 // Created by: blist at Thu Apr 29 11:19:00 2010
28 //
29 // Last update: Thu Apr 29 11:19:00 2010
30 //
31 #ifndef ROOT_Math_VavilovAccuratePdf
32 #define ROOT_Math_VavilovAccuratePdf
33
34
35 #include "Math/IParamFunction.h"
36 #include "Math/VavilovAccurate.h"
37
38 namespace ROOT {
39 namespace Math {
40
41 //____________________________________________________________________________
42 /**
43  Class describing the Vavilov pdf.
44
45  The probability density function of the Vavilov distribution
46  is given by:
47  \f[ p(\lambda; \kappa, \beta^2) =
48  \frac{1}{2 \pi i}\int_{c-i\infty}^{c+i\infty} \phi(s) e^{\lambda s} ds\f]
49  where \f$\phi(s) = e^{C} e^{\psi(s)}\f$
50  with \f$C = \kappa (1+\beta^2 \gamma )\f$
51  and \f[\psi(s) = s \ln \kappa + (s+\beta^2 \kappa)
52  \cdot \left ( \int \limits_{0}^{1}
53  \frac{1 - e^{\frac{-st}{\kappa}}}{t} \, dt- \gamma \right )
54  - \kappa \, e^{\frac{-s}{\kappa}}\f].
55  \f$\gamma = 0.5772156649\dots\f$ is Euler's constant.
56
57  The parameters are:
58  - 0: Norm: Normalization constant
59  - 1: x0: Location parameter
60  - 2: xi: Width parameter
61  - 3: kappa: Parameter \f$\kappa\f$ of the Vavilov distribution
62  - 4: beta2: Parameter \f$\beta^2\f$ of the Vavilov distribution
63
64  Benno List, June 2010
65
66  @ingroup StatFunc
67  */
68
69
71  public:
72
73  /**
74  Default constructor
75  */
77
78  /**
79  Constructor with parameter values
80  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
81  */
82  VavilovAccuratePdf (const double *p);
83
84  /**
85  Destructor
86  */
87  virtual ~VavilovAccuratePdf ();
88
89  /**
90  Access the parameter values
91  */
92  virtual const double * Parameters() const;
93
94  /**
95  Set the parameter values
96
97  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
98
99  */
100  virtual void SetParameters(const double * p );
101
102  /**
103  Return the number of Parameters
104  */
105  virtual unsigned int NPar() const;
106
107  /**
108  Return the name of the i-th parameter (starting from zero)
109  */
110  virtual std::string ParameterName(unsigned int i) const;
111
112  /**
113  Evaluate the function
114
115  @param x The Landau parameter \f$x = \lambda_L\f$
116  */
117  virtual double DoEval(double x) const;
118
119  /**
120  Evaluate the function, using parameters p
121
122  @param x The Landau parameter \f$x = \lambda_L\f$
123  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
124  */
125  virtual double DoEvalPar(double x, const double * p) const;
126
127  /**
128  Return a clone of the object
129  */
130  virtual IBaseFunctionOneDim * Clone() const;
131
132  private:
133  double fP[5];
134
135 };
136
137
138 } // namespace Math
139 } // namespace ROOT
140
141 #endif /* ROOT_Math_VavilovAccuratePdf */
Interface (abstract class) for generic functions objects of one-dimension Provides a method to evalua...
Definition: IFunction.h:134
virtual std::string ParameterName(unsigned int i) const
Return the name of the i-th parameter (starting from zero)
virtual double DoEvalPar(double x, const double *p) const
Evaluate the function, using parameters p.
Namespace for new ROOT classes and functions.
Definition: StringConv.hxx:21
virtual ~VavilovAccuratePdf()
Destructor.
virtual double DoEval(double x) const
Evaluate the function.
virtual unsigned int NPar() const
Return the number of Parameters.
Double_t x[n]
Definition: legend1.C:17
virtual void SetParameters(const double *p)
Set the parameter values.
virtual IBaseFunctionOneDim * Clone() const
Return a clone of the object.
Class describing the Vavilov pdf.
virtual const double * Parameters() const
Access the parameter values.
Specialized IParamFunction interface (abstract class) for one-dimensional parametric functions It is ...
VavilovAccuratePdf()
Default constructor.
Namespace for new Math classes and functions.