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). */ exp(Scalar x,int)24 static Scalar exp(Scalar x, int) 25 { 26 return std::exp(x); 27 } 28 29 /** \brief Cosine (and its derivatives). */ cos(Scalar x,int n)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). */ sin(Scalar x,int n)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). */ cosh(Scalar x,int n)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). */ sinh(Scalar x,int n)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 106