1 #ifndef LEPTON_CUSTOM_FUNCTION_H_ 2 #define LEPTON_CUSTOM_FUNCTION_H_ 3 4 /* -------------------------------------------------------------------------- * 5 * Lepton * 6 * -------------------------------------------------------------------------- * 7 * This is part of the Lepton expression parser originating from * 8 * Simbios, the NIH National Center for Physics-Based Simulation of * 9 * Biological Structures at Stanford, funded under the NIH Roadmap for * 10 * Medical Research, grant U54 GM072970. See https://simtk.org. * 11 * * 12 * Portions copyright (c) 2009 Stanford University and the Authors. * 13 * Authors: Peter Eastman * 14 * Contributors: * 15 * * 16 * Permission is hereby granted, free of charge, to any person obtaining a * 17 * copy of this software and associated documentation files (the "Software"), * 18 * to deal in the Software without restriction, including without limitation * 19 * the rights to use, copy, modify, merge, publish, distribute, sublicense, * 20 * and/or sell copies of the Software, and to permit persons to whom the * 21 * Software is furnished to do so, subject to the following conditions: * 22 * * 23 * The above copyright notice and this permission notice shall be included in * 24 * all copies or substantial portions of the Software. * 25 * * 26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * 27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * 28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * 29 * THE AUTHORS, CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * 30 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * 31 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE * 32 * USE OR OTHER DEALINGS IN THE SOFTWARE. * 33 * -------------------------------------------------------------------------- */ 34 35 #include "windowsIncludes.h" 36 37 namespace Lepton { 38 39 /** 40 * This class is the interface for defining your own function that may be included in expressions. 41 * To use it, create a concrete subclass that implements all of the virtual methods for each new function 42 * you want to define. Then when you call Parser::parse() to parse an expression, pass a map of 43 * function names to CustomFunction objects. 44 */ 45 46 class LEPTON_EXPORT CustomFunction { 47 public: ~CustomFunction()48 virtual ~CustomFunction() { 49 } 50 /** 51 * Get the number of arguments this function expects. 52 */ 53 virtual int getNumArguments() const = 0; 54 /** 55 * Evaluate the function. 56 * 57 * @param arguments the array of argument values 58 */ 59 virtual double evaluate(const double* arguments) const = 0; 60 /** 61 * Evaluate a derivative of the function. 62 * 63 * @param arguments the array of argument values 64 * @param derivOrder an array specifying the number of times the function has been differentiated 65 * with respect to each of its arguments. For example, the array {0, 2} indicates 66 * a second derivative with respect to the second argument. 67 */ 68 virtual double evaluateDerivative(const double* arguments, const int* derivOrder) const = 0; 69 /** 70 * Create a new duplicate of this object on the heap using the "new" operator. 71 */ 72 virtual CustomFunction* clone() const = 0; 73 }; 74 75 /** 76 * This class is an implementation of CustomFunction that does no computation. It just returns 77 * 0 for the value and derivatives. This is useful when using the parser to analyze expressions 78 * rather than to evaluate them. You can just create PlaceholderFunctions to represent any custom 79 * functions that may appear in expressions. 80 */ 81 82 class LEPTON_EXPORT PlaceholderFunction : public CustomFunction { 83 public: 84 /** 85 * Create a Placeholder function. 86 * 87 * @param numArgs the number of arguments the function expects 88 */ PlaceholderFunction(int numArgs)89 PlaceholderFunction(int numArgs) : numArgs(numArgs) { 90 } getNumArguments()91 int getNumArguments() const { 92 return numArgs; 93 } evaluate(const double * arguments)94 double evaluate(const double* arguments) const { 95 return 0.0; 96 } evaluateDerivative(const double * arguments,const int * derivOrder)97 double evaluateDerivative(const double* arguments, const int* derivOrder) const { 98 return 0.0; 99 } clone()100 CustomFunction* clone() const { 101 return new PlaceholderFunction(numArgs); 102 }; 103 private: 104 int numArgs; 105 }; 106 107 } // namespace Lepton 108 109 #endif /*LEPTON_CUSTOM_FUNCTION_H_*/ 110