1 // Ceres Solver - A fast non-linear least squares minimizer
2 // Copyright 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: strandmark@google.com (Petter Strandmark)
30 //
31 // Class for loading the data required for descibing a Fields of Experts (FoE)
32 // model.
33
34 #include "fields_of_experts.h"
35
36 #include <fstream>
37 #include <cmath>
38
39 #include "pgm_image.h"
40
41 namespace ceres {
42 namespace examples {
43
FieldsOfExpertsCost(const std::vector<double> & filter)44 FieldsOfExpertsCost::FieldsOfExpertsCost(const std::vector<double>& filter)
45 : filter_(filter) {
46 set_num_residuals(1);
47 for (int i = 0; i < filter_.size(); ++i) {
48 mutable_parameter_block_sizes()->push_back(1);
49 }
50 }
51
52 // This is a dot product between a the scalar parameters and a vector of filter
53 // coefficients.
Evaluate(double const * const * parameters,double * residuals,double ** jacobians) const54 bool FieldsOfExpertsCost::Evaluate(double const* const* parameters,
55 double* residuals,
56 double** jacobians) const {
57 int num_variables = filter_.size();
58 residuals[0] = 0;
59 for (int i = 0; i < num_variables; ++i) {
60 residuals[0] += filter_[i] * parameters[i][0];
61 }
62
63 if (jacobians != NULL) {
64 for (int i = 0; i < num_variables; ++i) {
65 if (jacobians[i] != NULL) {
66 jacobians[i][0] = filter_[i];
67 }
68 }
69 }
70
71 return true;
72 }
73
74 // This loss function builds the FoE terms and is equal to
75 //
76 // f(x) = alpha_i * log(1 + (1/2)s)
77 //
Evaluate(double sq_norm,double rho[3]) const78 void FieldsOfExpertsLoss::Evaluate(double sq_norm, double rho[3]) const {
79 const double c = 0.5;
80 const double sum = 1.0 + sq_norm * c;
81 const double inv = 1.0 / sum;
82 // 'sum' and 'inv' are always positive, assuming that 's' is.
83 rho[0] = alpha_ * log(sum);
84 rho[1] = alpha_ * c * inv;
85 rho[2] = - alpha_ * c * c * inv * inv;
86 }
87
FieldsOfExperts()88 FieldsOfExperts::FieldsOfExperts()
89 : size_(0), num_filters_(0) {
90 }
91
LoadFromFile(const std::string & filename)92 bool FieldsOfExperts::LoadFromFile(const std::string& filename) {
93 std::ifstream foe_file(filename.c_str());
94 foe_file >> size_;
95 foe_file >> num_filters_;
96 if (size_ < 0 || num_filters_ < 0) {
97 return false;
98 }
99 const int num_variables = NumVariables();
100
101 x_delta_indices_.resize(num_variables);
102 for (int i = 0; i < num_variables; ++i) {
103 foe_file >> x_delta_indices_[i];
104 }
105
106 y_delta_indices_.resize(NumVariables());
107 for (int i = 0; i < num_variables; ++i) {
108 foe_file >> y_delta_indices_[i];
109 }
110
111 alpha_.resize(num_filters_);
112 for (int i = 0; i < num_filters_; ++i) {
113 foe_file >> alpha_[i];
114 }
115
116 filters_.resize(num_filters_);
117 for (int i = 0; i < num_filters_; ++i) {
118 filters_[i].resize(num_variables);
119 for (int j = 0; j < num_variables; ++j) {
120 foe_file >> filters_[i][j];
121 }
122 }
123
124 // If any read failed, return failure.
125 if (!foe_file) {
126 size_ = 0;
127 return false;
128 }
129
130 // There cannot be anything else in the file. Try reading another number and
131 // return failure if that succeeded.
132 double temp;
133 foe_file >> temp;
134 if (foe_file) {
135 size_ = 0;
136 return false;
137 }
138
139 return true;
140 }
141
NewCostFunction(int alpha_index) const142 ceres::CostFunction* FieldsOfExperts::NewCostFunction(int alpha_index) const {
143 return new FieldsOfExpertsCost(filters_[alpha_index]);
144 }
145
NewLossFunction(int alpha_index) const146 ceres::LossFunction* FieldsOfExperts::NewLossFunction(int alpha_index) const {
147 return new FieldsOfExpertsLoss(alpha_[alpha_index]);
148 }
149
150
151 } // namespace examples
152 } // namespace ceres
153