Tanh.h 4.38 KB
 ext-rogers_c committed Jun 05, 2017 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 /* * Copyright (c) 2017, Chris Rogers * All rights reserved. * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * 3. Neither the name of STFC nor the names of its contributors may be used to * endorse or promote products derived from this software without specific * prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #ifndef ENDFIELDMODEL_TANH_H_  29 #define ENDFIELDMODEL_TANH_H_  ext-rogers_c committed Jun 05, 2017 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58  #include #include #include "AbsBeamline/EndFieldModel/EndFieldModel.h" namespace endfieldmodel { /** Calculate the Tanh function (e.g. for multipole end fields). * * DoubleTanh function is given by\n * \f$T(x) = (tanh( (x+x0)/\lambda )-tanh( (x-x0)/\lambda ))/2\f$\n * The derivatives of tanh(x) are given by\n * \f$d^p tanh(x)/dx^p = \sum_q I_{pq} tanh^{q}(x)\f$\n * where \f$I_{pq}\f$ are calculated using some recursion relation. Using these * expressions, one can calculate a recursion relation for higher order * derivatives and hence calculate analytical derivatives at arbitrary order. */ class Tanh : public EndFieldModel { public: /** Create a double tanh function * * Here x0 is the centre length and lambda is the end length. max_index is * used to set up for differentiation - don't try to calculate * higher differentials than exist in max_index. */ Tanh(double x0, double lambda, int max_index); /** Default constructor (initialises x0 and lambda to 0) */  59 60 61 62  Tanh() : _x0(0.), _lambda(0.) {setTanhDiffIndices(10);} /** Copy constructor */ Tanh(const Tanh& rhs) : _x0(rhs._x0), _lambda(rhs._lambda) {}  ext-rogers_c committed Jun 05, 2017 63 64  /** Destructor (no mallocs so does nothing) */  65  ~Tanh();  ext-rogers_c committed Jun 05, 2017 66   67 68  /** Inherited copy constructor. */ EndFieldModel* clone() const;  ext-rogers_c committed Jun 05, 2017 69 70 71 72  /** Double Tanh is given by\n * \f$d(x) = \f$ */  73  double function(double x, int n) const;  ext-rogers_c committed Jun 05, 2017 74 75  /** Returns the value of tanh((x+x0)/lambda) or its \f$n^{th}\f$ derivative. */  76  double getTanh(double x, int n) const;  ext-rogers_c committed Jun 05, 2017 77 78  /** Returns the value of tanh((x-x0)/lambda) or its \f$n^{th}\f$ derivative. */  79  double getNegTanh(double x, int n) const;  ext-rogers_c committed Jun 05, 2017 80 81 82 83 84 85  /** Get all the tanh differential indices \f$I_{pq}\f$. * * Returns vector of vector of ints where p indexes the differential and * q indexes the tanh power - so */  86  static std::vector< std::vector > getTanhDiffIndices(size_t n);  ext-rogers_c committed Jun 05, 2017 87 88  /** Set the value of tanh differential indices to nth order differentials. */  89  static void setTanhDiffIndices(size_t n);  ext-rogers_c committed Jun 05, 2017 90 91  /** Return lambda (end length) */  92  inline double getLambda() const {return _lambda;}  ext-rogers_c committed Jun 05, 2017 93 94  /** Return x0 (flat top length) */  95  inline double getX0() const {return _x0;}  ext-rogers_c committed Jun 05, 2017 96 97  /** Set lambda (end length) */  98  inline void setLambda(double lambda) {_lambda = lambda;}  ext-rogers_c committed Jun 05, 2017 99 100  /** Set x0 (flat top length) */  101 102 103  inline void setX0(double x0) {_x0 = x0;} /** Bug - does nothing */  Chris Rogers committed Oct 02, 2018 104  std::ostream& print(std::ostream& out) const;  ext-rogers_c committed Jun 05, 2017 105 106 107 108 109 110 111 112 113 114 115 116 117 118  private: double _x0, _lambda; /** _tdi indexes powers of tanh in d^n tanh/dx^n as sum of powers of tanh * * For some reason we index as n, +a, -a, but the third index is redundant */ static std::vector< std::vector< std::vector > > _tdi; }; } #endif