| 1 | // This file is part of Eigen, a lightweight C++ template library
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| 2 | // for linear algebra.
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| 3 | //
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| 4 | // Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
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| 5 | //
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| 6 | // This Source Code Form is subject to the terms of the Mozilla
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| 7 | // Public License v. 2.0. If a copy of the MPL was not distributed
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| 8 | // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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| 9 |
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| 10 | #ifndef EIGEN_STEM_FUNCTION
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| 11 | #define EIGEN_STEM_FUNCTION
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| 12 |
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| 13 | namespace Eigen {
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| 14 |
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| 15 | /** \ingroup MatrixFunctions_Module
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| 16 | * \brief Stem functions corresponding to standard mathematical functions.
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| 17 | */
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| 18 | template <typename Scalar>
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| 19 | class StdStemFunctions
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| 20 | {
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| 21 | public:
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| 22 |
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| 23 | /** \brief The exponential function (and its derivatives). */
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| 24 | static Scalar exp(Scalar x, int)
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| 25 | {
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| 26 | return std::exp(x);
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| 27 | }
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| 28 |
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| 29 | /** \brief Cosine (and its derivatives). */
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| 30 | static Scalar cos(Scalar x, int n)
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| 31 | {
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| 32 | Scalar res;
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| 33 | switch (n % 4) {
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| 34 | case 0:
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| 35 | res = std::cos(x);
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| 36 | break;
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| 37 | case 1:
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| 38 | res = -std::sin(x);
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| 39 | break;
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| 40 | case 2:
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| 41 | res = -std::cos(x);
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| 42 | break;
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| 43 | case 3:
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| 44 | res = std::sin(x);
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| 45 | break;
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| 46 | }
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| 47 | return res;
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| 48 | }
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| 49 |
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| 50 | /** \brief Sine (and its derivatives). */
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| 51 | static Scalar sin(Scalar x, int n)
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| 52 | {
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| 53 | Scalar res;
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| 54 | switch (n % 4) {
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| 55 | case 0:
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| 56 | res = std::sin(x);
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| 57 | break;
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| 58 | case 1:
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| 59 | res = std::cos(x);
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| 60 | break;
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| 61 | case 2:
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| 62 | res = -std::sin(x);
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| 63 | break;
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| 64 | case 3:
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| 65 | res = -std::cos(x);
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| 66 | break;
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| 67 | }
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| 68 | return res;
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| 69 | }
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| 70 |
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| 71 | /** \brief Hyperbolic cosine (and its derivatives). */
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| 72 | static Scalar cosh(Scalar x, int n)
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| 73 | {
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| 74 | Scalar res;
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| 75 | switch (n % 2) {
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| 76 | case 0:
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| 77 | res = std::cosh(x);
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| 78 | break;
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| 79 | case 1:
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| 80 | res = std::sinh(x);
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| 81 | break;
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| 82 | }
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| 83 | return res;
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| 84 | }
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| 85 |
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| 86 | /** \brief Hyperbolic sine (and its derivatives). */
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| 87 | static Scalar sinh(Scalar x, int n)
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| 88 | {
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| 89 | Scalar res;
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| 90 | switch (n % 2) {
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| 91 | case 0:
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| 92 | res = std::sinh(x);
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| 93 | break;
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| 94 | case 1:
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| 95 | res = std::cosh(x);
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| 96 | break;
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| 97 | }
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| 98 | return res;
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| 99 | }
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| 100 |
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| 101 | }; // end of class StdStemFunctions
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| 102 |
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| 103 | } // end namespace Eigen
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| 104 |
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| 105 | #endif // EIGEN_STEM_FUNCTION
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