1 // Ceres Solver - A fast non-linear least squares minimizer 2 // Copyright 2010, 2011, 2012 Google Inc. All rights reserved. 3 // http://code.google.com/p/ceres-solver/ 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 // keir@google.com (Keir Mierle) 31 // 32 // Purpose : Class and struct definitions for parameter and residual blocks. 33 34 #ifndef CERES_INTERNAL_RESIDUAL_BLOCK_H_ 35 #define CERES_INTERNAL_RESIDUAL_BLOCK_H_ 36 37 #include <string> 38 #include <vector> 39 40 #include "ceres/cost_function.h" 41 #include "ceres/internal/port.h" 42 #include "ceres/internal/scoped_ptr.h" 43 #include "ceres/stringprintf.h" 44 #include "ceres/types.h" 45 46 namespace ceres { 47 48 class LossFunction; 49 50 namespace internal { 51 52 class ParameterBlock; 53 54 // A term in the least squares problem. The mathematical form of each term in 55 // the overall least-squares cost function is: 56 // 57 // 1 58 // --- loss_function( || cost_function(block1, block2, ...) ||^2 ), 59 // 2 60 // 61 // Storing the cost function and the loss function separately permits optimizing 62 // the problem with standard non-linear least techniques, without requiring a 63 // more general non-linear solver. 64 // 65 // The residual block stores pointers to but does not own the cost functions, 66 // loss functions, and parameter blocks. 67 class ResidualBlock { 68 public: 69 // Construct the residual block with the given cost/loss functions. Loss may 70 // be null. The index is the index of the residual block in the Program's 71 // residual_blocks array. 72 ResidualBlock(const CostFunction* cost_function, 73 const LossFunction* loss_function, 74 const vector<ParameterBlock*>& parameter_blocks, 75 int index); 76 77 // Evaluates the residual term, storing the scalar cost in *cost, the residual 78 // components in *residuals, and the jacobians between the parameters and 79 // residuals in jacobians[i], in row-major order. If residuals is NULL, the 80 // residuals are not computed. If jacobians is NULL, no jacobians are 81 // computed. If jacobians[i] is NULL, then the jacobian for that parameter is 82 // not computed. 83 // 84 // Evaluate needs scratch space which must be supplied by the caller via 85 // scratch. The array should have at least NumScratchDoublesForEvaluate() 86 // space available. 87 // 88 // The return value indicates the success or failure. If the function returns 89 // false, the caller should expect the the output memory locations to have 90 // been modified. 91 // 92 // The returned cost and jacobians have had robustification and local 93 // parameterizations applied already; for example, the jacobian for a 94 // 4-dimensional quaternion parameter using the "QuaternionParameterization" 95 // is num_residuals by 3 instead of num_residuals by 4. 96 // 97 // apply_loss_function as the name implies allows the user to switch 98 // the application of the loss function on and off. 99 bool Evaluate(bool apply_loss_function, 100 double* cost, 101 double* residuals, 102 double** jacobians, 103 double* scratch) const; 104 105 cost_function()106 const CostFunction* cost_function() const { return cost_function_; } loss_function()107 const LossFunction* loss_function() const { return loss_function_; } 108 109 // Access the parameter blocks for this residual. The array has size 110 // NumParameterBlocks(). parameter_blocks()111 ParameterBlock* const* parameter_blocks() const { 112 return parameter_blocks_.get(); 113 } 114 115 // Number of variable blocks that this residual term depends on. NumParameterBlocks()116 int NumParameterBlocks() const { 117 return cost_function_->parameter_block_sizes().size(); 118 } 119 120 // The size of the residual vector returned by this residual function. NumResiduals()121 int NumResiduals() const { return cost_function_->num_residuals(); } 122 123 // The minimum amount of scratch space needed to pass to Evaluate(). 124 int NumScratchDoublesForEvaluate() const; 125 126 // This residual block's index in an array. index()127 int index() const { return index_; } set_index(int index)128 void set_index(int index) { index_ = index; } 129 ToString()130 string ToString() { 131 return StringPrintf("{residual block; index=%d}", index_); 132 } 133 134 private: 135 const CostFunction* cost_function_; 136 const LossFunction* loss_function_; 137 scoped_array<ParameterBlock*> parameter_blocks_; 138 139 // The index of the residual, typically in a Program. This is only to permit 140 // switching from a ResidualBlock* to an index in the Program's array, needed 141 // to do efficient removals. 142 int32 index_; 143 }; 144 145 } // namespace internal 146 } // namespace ceres 147 148 #endif // CERES_INTERNAL_RESIDUAL_BLOCK_H_ 149