| Brian Silverman | 72890c2 | 2015-09-19 14:37:37 -0400 | [diff] [blame^] | 1 | // This file is part of Eigen, a lightweight C++ template library |
| 2 | // for linear algebra. |
| 3 | // |
| 4 | // Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk> |
| 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 | #ifndef EIGEN_STEM_FUNCTION |
| 11 | #define EIGEN_STEM_FUNCTION |
| 12 | |
| 13 | namespace Eigen { |
| 14 | |
| 15 | /** \ingroup MatrixFunctions_Module |
| 16 | * \brief Stem functions corresponding to standard mathematical functions. |
| 17 | */ |
| 18 | template <typename Scalar> |
| 19 | class StdStemFunctions |
| 20 | { |
| 21 | public: |
| 22 | |
| 23 | /** \brief The exponential function (and its derivatives). */ |
| 24 | static Scalar exp(Scalar x, int) |
| 25 | { |
| 26 | return std::exp(x); |
| 27 | } |
| 28 | |
| 29 | /** \brief Cosine (and its derivatives). */ |
| 30 | static Scalar cos(Scalar x, int n) |
| 31 | { |
| 32 | Scalar res; |
| 33 | switch (n % 4) { |
| 34 | case 0: |
| 35 | res = std::cos(x); |
| 36 | break; |
| 37 | case 1: |
| 38 | res = -std::sin(x); |
| 39 | break; |
| 40 | case 2: |
| 41 | res = -std::cos(x); |
| 42 | break; |
| 43 | case 3: |
| 44 | res = std::sin(x); |
| 45 | break; |
| 46 | } |
| 47 | return res; |
| 48 | } |
| 49 | |
| 50 | /** \brief Sine (and its derivatives). */ |
| 51 | static Scalar sin(Scalar x, int n) |
| 52 | { |
| 53 | Scalar res; |
| 54 | switch (n % 4) { |
| 55 | case 0: |
| 56 | res = std::sin(x); |
| 57 | break; |
| 58 | case 1: |
| 59 | res = std::cos(x); |
| 60 | break; |
| 61 | case 2: |
| 62 | res = -std::sin(x); |
| 63 | break; |
| 64 | case 3: |
| 65 | res = -std::cos(x); |
| 66 | break; |
| 67 | } |
| 68 | return res; |
| 69 | } |
| 70 | |
| 71 | /** \brief Hyperbolic cosine (and its derivatives). */ |
| 72 | static Scalar cosh(Scalar x, int n) |
| 73 | { |
| 74 | Scalar res; |
| 75 | switch (n % 2) { |
| 76 | case 0: |
| 77 | res = std::cosh(x); |
| 78 | break; |
| 79 | case 1: |
| 80 | res = std::sinh(x); |
| 81 | break; |
| 82 | } |
| 83 | return res; |
| 84 | } |
| 85 | |
| 86 | /** \brief Hyperbolic sine (and its derivatives). */ |
| 87 | static Scalar sinh(Scalar x, int n) |
| 88 | { |
| 89 | Scalar res; |
| 90 | switch (n % 2) { |
| 91 | case 0: |
| 92 | res = std::sinh(x); |
| 93 | break; |
| 94 | case 1: |
| 95 | res = std::cosh(x); |
| 96 | break; |
| 97 | } |
| 98 | return res; |
| 99 | } |
| 100 | |
| 101 | }; // end of class StdStemFunctions |
| 102 | |
| 103 | } // end namespace Eigen |
| 104 | |
| 105 | #endif // EIGEN_STEM_FUNCTION |