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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 #include <string>
39 
40 namespace ROOT {
41 namespace Math {
42 
43 //____________________________________________________________________________
44 /**
45  Class describing the Vavilov pdf.
46 
47  The probability density function of the Vavilov distribution
48  is given by:
49  \f[ p(\lambda; \kappa, \beta^2) =
50  \frac{1}{2 \pi i}\int_{c-i\infty}^{c+i\infty} \phi(s) e^{\lambda s} ds\f]
51  where \f$\phi(s) = e^{C} e^{\psi(s)}\f$
52  with \f$ C = \kappa (1+\beta^2 \gamma )\f$
53  and \f[\psi(s) = s \ln \kappa + (s+\beta^2 \kappa)
54  \cdot \left ( \int \limits_{0}^{1}
55  \frac{1 - e^{\frac{-st}{\kappa}}}{t} \, dt- \gamma \right )
56  - \kappa \, e^{\frac{-s}{\kappa}}\f].
57  \f$ \gamma = 0.5772156649\dots\f$ is Euler's constant.
58 
59  The parameters are:
60  - 0: Norm: Normalization constant
61  - 1: x0: Location parameter
62  - 2: xi: Width parameter
63  - 3: kappa: Parameter \f$\kappa\f$ of the Vavilov distribution
64  - 4: beta2: Parameter \f$\beta^2\f$ of the Vavilov distribution
65 
66  Benno List, June 2010
67 
68  @ingroup StatFunc
69  */
70 
71 
72 class VavilovAccuratePdf: public IParametricFunctionOneDim {
73  public:
74 
75  /**
76  Default constructor
77  */
79 
80  /**
81  Constructor with parameter values
82  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
83  */
84  VavilovAccuratePdf (const double *p);
85 
86  /**
87  Destructor
88  */
89  virtual ~VavilovAccuratePdf ();
90 
91  /**
92  Access the parameter values
93  */
94  virtual const double * Parameters() const;
95 
96  /**
97  Set the parameter values
98 
99  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
100 
101  */
102  virtual void SetParameters(const double * p );
103 
104  /**
105  Return the number of Parameters
106  */
107  virtual unsigned int NPar() const;
108 
109  /**
110  Return the name of the i-th parameter (starting from zero)
111  */
112  virtual std::string ParameterName(unsigned int i) const;
113 
114  /**
115  Evaluate the function
116 
117  @param x The Landau parameter \f$x = \lambda_L\f$
118  */
119  virtual double DoEval(double x) const;
120 
121  /**
122  Evaluate the function, using parameters p
123 
124  @param x The Landau parameter \f$x = \lambda_L\f$
125  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
126  */
127  virtual double DoEvalPar(double x, const double * p) const;
128 
129  /**
130  Return a clone of the object
131  */
132  virtual IBaseFunctionOneDim * Clone() const;
133 
134  private:
135  double fP[5];
136 
137 };
138 
139 
140 } // namespace Math
141 } // namespace ROOT
142 
143 #endif /* ROOT_Math_VavilovAccuratePdf */
ROOT::Math::VavilovAccuratePdf::Parameters
virtual const double * Parameters() const
Access the parameter values.
Definition: VavilovAccuratePdf.cxx:102
ROOT::Math::VavilovAccuratePdf::fP
double fP[5]
Definition: VavilovAccuratePdf.h:192
ROOT::Math::VavilovAccuratePdf::VavilovAccuratePdf
VavilovAccuratePdf()
Default constructor.
Definition: VavilovAccuratePdf.cxx:78
x
Double_t x[n]
Definition: legend1.C:17
ROOT::Math::VavilovAccuratePdf::ParameterName
virtual std::string ParameterName(unsigned int i) const
Return the name of the i-th parameter (starting from zero)
Definition: VavilovAccuratePdf.cxx:116
ROOT::Math::VavilovAccuratePdf::~VavilovAccuratePdf
virtual ~VavilovAccuratePdf()
Destructor.
Definition: VavilovAccuratePdf.cxx:99
ROOT::Math::VavilovAccuratePdf::DoEvalPar
virtual double DoEvalPar(double x, const double *p) const
Evaluate the function, using parameters p.
Definition: VavilovAccuratePdf.cxx:132
ROOT::Math::VavilovAccuratePdf::DoEval
virtual double DoEval(double x) const
Evaluate the function.
Definition: VavilovAccuratePdf.cxx:127
IParamFunction.h
ROOT::Math::IBaseFunctionOneDim
Interface (abstract class) for generic functions objects of one-dimension Provides a method to evalua...
Definition: IFunction.h:135
ROOT::Math::VavilovAccuratePdf::NPar
virtual unsigned int NPar() const
Return the number of Parameters.
Definition: VavilovAccuratePdf.cxx:112
VavilovAccurate.h
ROOT::Math::VavilovAccuratePdf::Clone
virtual IBaseFunctionOneDim * Clone() const
Return a clone of the object.
Definition: VavilovAccuratePdf.cxx:139
ROOT::Math::VavilovAccuratePdf::SetParameters
virtual void SetParameters(const double *p)
Set the parameter values.
Definition: VavilovAccuratePdf.cxx:106
ROOT
VSD Structures.
Definition: StringConv.hxx:21
Math