Logo ROOT  
Reference Guide
VavilovAccuratePdf.h
Go to the documentation of this file.
1// @(#)root/mathmore:$Id$
2// Authors: B. List 29.4.2010
3
4 /**********************************************************************
5 * *
6 * Copyright (c) 2004 ROOT Foundation, CERN/PH-SFT *
7 * *
8 * This library is free software; you can redistribute it and/or *
9 * modify it under the terms of the GNU General Public License *
10 * as published by the Free Software Foundation; either version 2 *
11 * of the License, or (at your option) any later version. *
12 * *
13 * This library is distributed in the hope that it will be useful, *
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
16 * General Public License for more details. *
17 * *
18 * You should have received a copy of the GNU General Public License *
19 * along with this library (see file COPYING); if not, write *
20 * to the Free Software Foundation, Inc., 59 Temple Place, Suite *
21 * 330, Boston, MA 02111-1307 USA, or contact the author. *
22 * *
23 **********************************************************************/
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"
37
38#include <string>
39
40namespace ROOT {
41namespace 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
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 */
Interface (abstract class) for generic functions objects of one-dimension Provides a method to evalua...
Definition: IFunction.h:135
Specialized IParamFunction interface (abstract class) for one-dimensional parametric functions It is ...
Class describing the Vavilov pdf.
virtual ~VavilovAccuratePdf()
Destructor.
virtual double DoEvalPar(double x, const double *p) const
Evaluate the function, using parameters p.
virtual std::string ParameterName(unsigned int i) const
Return the name of the i-th parameter (starting from zero)
virtual void SetParameters(const double *p)
Set the parameter values.
virtual IBaseFunctionOneDim * Clone() const
Return a clone of the object.
VavilovAccuratePdf()
Default constructor.
virtual const double * Parameters() const
Access the parameter values.
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
Namespace for new Math classes and functions.
tbb::task_arena is an alias of tbb::interface7::task_arena, which doesn't allow to forward declare tb...