1 //                                               -*- C++ -*-
2 /**
3  *  @brief Krawtchouk polynomial factory
4  *
5  *  Copyright 2005-2021 Airbus-EDF-IMACS-ONERA-Phimeca
6  *
7  *  This library is free software: you can redistribute it and/or modify
8  *  it under the terms of the GNU Lesser General Public License as published by
9  *  the Free Software Foundation, either version 3 of the License, or
10  *  (at your option) any later version.
11  *
12  *  This library is distributed in the hope that it will be useful,
13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *  GNU Lesser General Public License for more details.
16  *
17  *  You should have received a copy of the GNU Lesser General Public License
18  *  along with this library.  If not, see <http://www.gnu.org/licenses/>.
19  *
20  */
21 #ifndef OPENTURNS_KRAWTCHOUKFACTORY_HXX
22 #define OPENTURNS_KRAWTCHOUKFACTORY_HXX
23 
24 #include "openturns/OrthogonalUniVariatePolynomialFactory.hxx"
25 
26 BEGIN_NAMESPACE_OPENTURNS
27 
28 
29 
30 /**
31  * @class KrawtchoukFactory
32  *
33  * Krawtchouk polynomial factory
34  */
35 
36 class OT_API KrawtchoukFactory
37   : public OrthogonalUniVariatePolynomialFactory
38 {
39   CLASSNAME
40 public:
41 
42 
43   /** Default constructor: (1, 0.5) order Krawtchouk polynomial associated with the default Binomial() = Binomial(1, 0.5) distribution which is equal to the Bernoulli(0.5) distribution */
44   KrawtchoukFactory();
45 
46   /** Parameter constructor: (n, p) is the order of the Krawtchouk polynomial, associated with the Binomial(n, p) distribution */
47   KrawtchoukFactory(const UnsignedInteger n,
48                     const Scalar p);
49 
50   /** Virtual constructor */
51   KrawtchoukFactory * clone() const override;
52 
53   /** Calculate the coefficients of recurrence a0n, a1n, a2n such that
54       Pn+1(x) = (a0n * x + a1n) * Pn(x) + a2n * Pn-1(x) */
55   Coefficients getRecurrenceCoefficients(const UnsignedInteger n) const override;
56 
57   /** N accessor */
58   UnsignedInteger getN() const;
59 
60   /** P accessor */
61   Scalar getP() const;
62 
63   /** String converter */
64   String __repr__() const override;
65 
66   /** Method save() stores the object through the StorageManager */
67   void save(Advocate & adv) const override;
68 
69   /** Method load() reloads the object from the StorageManager */
70   void load(Advocate & adv) override;
71 
72 private:
73   /* First parameter of the Krawtchouk polynomial */
74   UnsignedInteger n_;
75   /* Second parameter of the Krawtchouk polynomial */
76   Scalar p_;
77 
78 } ; /* class KrawtchoukFactory */
79 
80 
81 END_NAMESPACE_OPENTURNS
82 
83 #endif /* OPENTURNS_KRAWTCHOUKFACTORY_HXX */
84