1 // Ceres Solver - A fast non-linear least squares minimizer 2 // Copyright 2017 Google Inc. All rights reserved. 3 // http://ceres-solver.org/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are met: 7 // 8 // * Redistributions of source code must retain the above copyright notice, 9 // this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above copyright notice, 11 // this list of conditions and the following disclaimer in the documentation 12 // and/or other materials provided with the distribution. 13 // * Neither the name of Google Inc. nor the names of its contributors may be 14 // used to endorse or promote products derived from this software without 15 // specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 18 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 21 // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 // POSSIBILITY OF SUCH DAMAGE. 28 // 29 // Author: sameeragarwal@google.com (Sameer Agarwal) 30 31 #ifndef CERES_INTERNAL_FUNCTION_SAMPLE_H_ 32 #define CERES_INTERNAL_FUNCTION_SAMPLE_H_ 33 34 #include <string> 35 #include "ceres/internal/eigen.h" 36 37 namespace ceres { 38 namespace internal { 39 40 // FunctionSample is used by the line search routines to store and 41 // communicate the value and (optionally) the gradient of the function 42 // being minimized. 43 // 44 // Since line search as the name implies happens along a certain 45 // line/direction. FunctionSample contains the information in two 46 // ways. Information in the ambient space and information along the 47 // direction of search. 48 struct FunctionSample { 49 FunctionSample(); 50 FunctionSample(double x, double value); 51 FunctionSample(double x, double value, double gradient); 52 53 std::string ToDebugString() const; 54 55 // x is the location of the sample along the search direction. 56 double x; 57 58 // Let p be a point and d be the search direction then 59 // 60 // vector_x = p + x * d; 61 Vector vector_x; 62 // True if vector_x has been assigned a valid value. 63 bool vector_x_is_valid; 64 65 // value = f(vector_x) 66 double value; 67 // True of the evaluation was successful and value is a finite 68 // number. 69 bool value_is_valid; 70 71 // vector_gradient = Df(vector_position); 72 // 73 // D is the derivative operator. 74 Vector vector_gradient; 75 // True if the vector gradient was evaluated and the evaluation was 76 // successful (the value is a finite number). 77 bool vector_gradient_is_valid; 78 79 // gradient = d.transpose() * vector_gradient 80 // 81 // where d is the search direction. 82 double gradient; 83 // True if the evaluation of the gradient was sucessful and the 84 // value is a finite number. 85 bool gradient_is_valid; 86 }; 87 88 89 90 91 } // namespace internal 92 } // namespace ceres 93 94 #endif // CERES_INTERNAL_FUNCTION_SAMPLE_H_ 95