blob: ed415db990da5008c12479f1acacdeace464f9c2 [file] [log] [blame]
Austin Schuh189376f2018-12-20 22:11:15 +11001// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2016 Gael Guennebaud <gael.guennebaud@inria.fr>
5//
6// This Source Code Form is subject to the terms of the Mozilla
7// Public License v. 2.0. If a copy of the MPL was not distributed
8// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
9
10
11#ifndef EIGEN_SPECIALFUNCTIONS_ARRAYAPI_H
12#define EIGEN_SPECIALFUNCTIONS_ARRAYAPI_H
13
14namespace Eigen {
15
16/** \cpp11 \returns an expression of the coefficient-wise igamma(\a a, \a x) to the given arrays.
17 *
18 * This function computes the coefficient-wise incomplete gamma function.
19 *
20 * \note This function supports only float and double scalar types in c++11 mode. To support other scalar types,
21 * or float/double in non c++11 mode, the user has to provide implementations of igammac(T,T) for any scalar
22 * type T to be supported.
23 *
24 * \sa Eigen::igammac(), Eigen::lgamma()
25 */
26template<typename Derived,typename ExponentDerived>
27inline const Eigen::CwiseBinaryOp<Eigen::internal::scalar_igamma_op<typename Derived::Scalar>, const Derived, const ExponentDerived>
28igamma(const Eigen::ArrayBase<Derived>& a, const Eigen::ArrayBase<ExponentDerived>& x)
29{
30 return Eigen::CwiseBinaryOp<Eigen::internal::scalar_igamma_op<typename Derived::Scalar>, const Derived, const ExponentDerived>(
31 a.derived(),
32 x.derived()
33 );
34}
35
36/** \cpp11 \returns an expression of the coefficient-wise igammac(\a a, \a x) to the given arrays.
37 *
38 * This function computes the coefficient-wise complementary incomplete gamma function.
39 *
40 * \note This function supports only float and double scalar types in c++11 mode. To support other scalar types,
41 * or float/double in non c++11 mode, the user has to provide implementations of igammac(T,T) for any scalar
42 * type T to be supported.
43 *
44 * \sa Eigen::igamma(), Eigen::lgamma()
45 */
46template<typename Derived,typename ExponentDerived>
47inline const Eigen::CwiseBinaryOp<Eigen::internal::scalar_igammac_op<typename Derived::Scalar>, const Derived, const ExponentDerived>
48igammac(const Eigen::ArrayBase<Derived>& a, const Eigen::ArrayBase<ExponentDerived>& x)
49{
50 return Eigen::CwiseBinaryOp<Eigen::internal::scalar_igammac_op<typename Derived::Scalar>, const Derived, const ExponentDerived>(
51 a.derived(),
52 x.derived()
53 );
54}
55
56/** \cpp11 \returns an expression of the coefficient-wise polygamma(\a n, \a x) to the given arrays.
57 *
58 * It returns the \a n -th derivative of the digamma(psi) evaluated at \c x.
59 *
60 * \note This function supports only float and double scalar types in c++11 mode. To support other scalar types,
61 * or float/double in non c++11 mode, the user has to provide implementations of polygamma(T,T) for any scalar
62 * type T to be supported.
63 *
64 * \sa Eigen::digamma()
65 */
66// * \warning Be careful with the order of the parameters: x.polygamma(n) is equivalent to polygamma(n,x)
67// * \sa ArrayBase::polygamma()
68template<typename DerivedN,typename DerivedX>
69inline const Eigen::CwiseBinaryOp<Eigen::internal::scalar_polygamma_op<typename DerivedX::Scalar>, const DerivedN, const DerivedX>
70polygamma(const Eigen::ArrayBase<DerivedN>& n, const Eigen::ArrayBase<DerivedX>& x)
71{
72 return Eigen::CwiseBinaryOp<Eigen::internal::scalar_polygamma_op<typename DerivedX::Scalar>, const DerivedN, const DerivedX>(
73 n.derived(),
74 x.derived()
75 );
76}
77
78/** \cpp11 \returns an expression of the coefficient-wise betainc(\a x, \a a, \a b) to the given arrays.
79 *
80 * This function computes the regularized incomplete beta function (integral).
81 *
82 * \note This function supports only float and double scalar types in c++11 mode. To support other scalar types,
83 * or float/double in non c++11 mode, the user has to provide implementations of betainc(T,T,T) for any scalar
84 * type T to be supported.
85 *
86 * \sa Eigen::betainc(), Eigen::lgamma()
87 */
88template<typename ArgADerived, typename ArgBDerived, typename ArgXDerived>
89inline const Eigen::CwiseTernaryOp<Eigen::internal::scalar_betainc_op<typename ArgXDerived::Scalar>, const ArgADerived, const ArgBDerived, const ArgXDerived>
90betainc(const Eigen::ArrayBase<ArgADerived>& a, const Eigen::ArrayBase<ArgBDerived>& b, const Eigen::ArrayBase<ArgXDerived>& x)
91{
92 return Eigen::CwiseTernaryOp<Eigen::internal::scalar_betainc_op<typename ArgXDerived::Scalar>, const ArgADerived, const ArgBDerived, const ArgXDerived>(
93 a.derived(),
94 b.derived(),
95 x.derived()
96 );
97}
98
99
100/** \returns an expression of the coefficient-wise zeta(\a x, \a q) to the given arrays.
101 *
102 * It returns the Riemann zeta function of two arguments \a x and \a q:
103 *
104 * \param x is the exposent, it must be > 1
105 * \param q is the shift, it must be > 0
106 *
107 * \note This function supports only float and double scalar types. To support other scalar types, the user has
108 * to provide implementations of zeta(T,T) for any scalar type T to be supported.
109 *
110 * \sa ArrayBase::zeta()
111 */
112template<typename DerivedX,typename DerivedQ>
113inline const Eigen::CwiseBinaryOp<Eigen::internal::scalar_zeta_op<typename DerivedX::Scalar>, const DerivedX, const DerivedQ>
114zeta(const Eigen::ArrayBase<DerivedX>& x, const Eigen::ArrayBase<DerivedQ>& q)
115{
116 return Eigen::CwiseBinaryOp<Eigen::internal::scalar_zeta_op<typename DerivedX::Scalar>, const DerivedX, const DerivedQ>(
117 x.derived(),
118 q.derived()
119 );
120}
121
122} // end namespace Eigen
123
124#endif // EIGEN_SPECIALFUNCTIONS_ARRAYAPI_H