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VavilovAccurateCdf.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 VavilovAccurateCdf
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_VavilovAccurateCdf
32 #define ROOT_Math_VavilovAccurateCdf
33 
34 #include "Math/IParamFunction.h"
35 #include "Math/VavilovAccurate.h"
36 
37 #include <string>
38 
39 namespace ROOT {
40 namespace Math {
41 
42 //____________________________________________________________________________
43 /**
44  Class describing the Vavilov cdf.
45 
46  The probability density function of the Vavilov distribution
47  is given by:
48  \f[ p(\lambda; \kappa, \beta^2) =
49  \frac{1}{2 \pi i}\int_{c-i\infty}^{c+i\infty} \phi(s) e^{\lambda s} ds\f]
50  where \f$\phi(s) = e^{C} e^{\psi(s)}\f$
51  with \f$ C = \kappa (1+\beta^2 \gamma )\f$
52  and \f[\psi(s) = s \ln \kappa + (s+\beta^2 \kappa)
53  \cdot \left ( \int \limits_{0}^{1}
54  \frac{1 - e^{\frac{-st}{\kappa}}}{t} \, dt - \gamma \right )
55  - \kappa \, e^{\frac{-s}{\kappa}}\f].
56  \f$ \gamma = 0.5772156649\dots\f$ is Euler's constant.
57 
58  The parameters are:
59  - 0: Norm: Normalization constant
60  - 1: x0: Location parameter
61  - 2: xi: Width parameter
62  - 3: kappa: Parameter \f$\kappa\f$ of the Vavilov distribution
63  - 4: beta2: Parameter \f$\beta^2\f$ of the Vavilov distribution
64 
65  Benno List, June 2010
66 
67 
68  @ingroup StatFunc
69  */
70 
71 
72 class VavilovAccurateCdf: 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  VavilovAccurateCdf(const double *p);
85 
86  /**
87  Destructor
88  */
89  virtual ~VavilovAccurateCdf ();
90 
91  /**
92  Access the parameter values
93  */
94  virtual const double * Parameters() const;
95 
96  /**
97  Set the parameter values
98  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
99 
100  */
101  virtual void SetParameters(const double * p );
102 
103  /**
104  Return the number of Parameters
105  */
106  virtual unsigned int NPar() const;
107 
108  /**
109  Return the name of the i-th parameter (starting from zero)
110  Overwrite if want to avoid the default name ("Par_0, Par_1, ...")
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  */
120  virtual double DoEval(double x) const;
121 
122  /**
123  Evaluate the function, using parameters p
124 
125  @param x The Landau parameter \f$x = \lambda_L\f$
126  @param p vector of doubles containing the parameter values (Norm, x0, xi, kappa, beta2).
127  */
128  virtual double DoEvalPar(double x, const double * p) const;
129 
130  /**
131  Return a clone of the object
132  */
133  virtual IBaseFunctionOneDim * Clone() const;
134 
135  private:
136  double fP[5];
137 
138 };
139 
140 
141 } // namespace Math
142 } // namespace ROOT
143 
144 #endif /* ROOT_Math_VavilovAccurateCdf */
ROOT::Math::VavilovAccurateCdf::ParameterName
virtual std::string ParameterName(unsigned int i) const
Return the name of the i-th parameter (starting from zero) Overwrite if want to avoid the default nam...
Definition: VavilovAccurateCdf.cxx:116
ROOT::Math::VavilovAccurateCdf::Clone
virtual IBaseFunctionOneDim * Clone() const
Return a clone of the object.
Definition: VavilovAccurateCdf.cxx:139
x
Double_t x[n]
Definition: legend1.C:17
ROOT::Math::VavilovAccurateCdf::VavilovAccurateCdf
VavilovAccurateCdf()
Default constructor.
Definition: VavilovAccurateCdf.cxx:78
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::VavilovAccurateCdf::SetParameters
virtual void SetParameters(const double *p)
Set the parameter values.
Definition: VavilovAccurateCdf.cxx:106
ROOT::Math::VavilovAccurateCdf::fP
double fP[5]
Definition: VavilovAccurateCdf.h:193
ROOT::Math::VavilovAccurateCdf::~VavilovAccurateCdf
virtual ~VavilovAccurateCdf()
Destructor.
Definition: VavilovAccurateCdf.cxx:99
ROOT::Math::VavilovAccurateCdf::DoEval
virtual double DoEval(double x) const
Evaluate the function.
Definition: VavilovAccurateCdf.cxx:127
VavilovAccurate.h
ROOT::Math::VavilovAccurateCdf::DoEvalPar
virtual double DoEvalPar(double x, const double *p) const
Evaluate the function, using parameters p.
Definition: VavilovAccurateCdf.cxx:132
ROOT::Math::VavilovAccurateCdf::NPar
virtual unsigned int NPar() const
Return the number of Parameters.
Definition: VavilovAccurateCdf.cxx:112
ROOT
VSD Structures.
Definition: StringConv.hxx:21
Math
ROOT::Math::VavilovAccurateCdf::Parameters
virtual const double * Parameters() const
Access the parameter values.
Definition: VavilovAccurateCdf.cxx:102