1 // Ceres Solver - A fast non-linear least squares minimizer
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29 // Author: wjr@google.com (William Rucklidge)
30 //
31 // Tests for the conditioned cost function.
32 
33 #include "ceres/conditioned_cost_function.h"
34 
35 #include "ceres/internal/eigen.h"
36 #include "ceres/normal_prior.h"
37 #include "ceres/types.h"
38 #include "gtest/gtest.h"
39 
40 namespace ceres {
41 namespace internal {
42 
43 // The size of the cost functions we build.
44 static const int kTestCostFunctionSize = 3;
45 
46 // A simple cost function: return ax + b.
47 class LinearCostFunction : public CostFunction {
48  public:
LinearCostFunction(double a,double b)49   LinearCostFunction(double a, double b) : a_(a), b_(b) {
50     set_num_residuals(1);
51     mutable_parameter_block_sizes()->push_back(1);
52   }
53 
Evaluate(double const * const * parameters,double * residuals,double ** jacobians) const54   virtual bool Evaluate(double const* const* parameters,
55                         double* residuals,
56                         double** jacobians) const {
57     *residuals = **parameters * a_ + b_;
58     if (jacobians && *jacobians) {
59       **jacobians = a_;
60     }
61 
62     return true;
63   }
64 
65  private:
66   const double a_, b_;
67 };
68 
69 // Tests that ConditionedCostFunction does what it's supposed to.
TEST(CostFunctionTest,ConditionedCostFunction)70 TEST(CostFunctionTest, ConditionedCostFunction) {
71   double v1[kTestCostFunctionSize], v2[kTestCostFunctionSize],
72       jac[kTestCostFunctionSize * kTestCostFunctionSize],
73       result[kTestCostFunctionSize];
74 
75   for (int i = 0; i < kTestCostFunctionSize; i++) {
76     v1[i] = i;
77     v2[i] = i * 10;
78     // Seed a few garbage values in the Jacobian matrix, to make sure that
79     // they're overwritten.
80     jac[i * 2] = i * i;
81     result[i] = i * i * i;
82   }
83 
84   // Make a cost function that computes x - v2
85   VectorRef v2_vector(v2, kTestCostFunctionSize, 1);
86   Matrix identity(kTestCostFunctionSize, kTestCostFunctionSize);
87   identity.setIdentity();
88   NormalPrior* difference_cost_function = new NormalPrior(identity, v2_vector);
89 
90   vector<CostFunction*> conditioners;
91   for (int i = 0; i < kTestCostFunctionSize; i++) {
92     conditioners.push_back(new LinearCostFunction(i + 2, i * 7));
93   }
94 
95   ConditionedCostFunction conditioned_cost_function(difference_cost_function,
96                                                     conditioners,
97                                                     TAKE_OWNERSHIP);
98   EXPECT_EQ(difference_cost_function->num_residuals(),
99             conditioned_cost_function.num_residuals());
100   EXPECT_EQ(difference_cost_function->parameter_block_sizes(),
101             conditioned_cost_function.parameter_block_sizes());
102 
103   double *parameters[1];
104   parameters[0] = v1;
105   double *jacs[1];
106   jacs[0] = jac;
107 
108   conditioned_cost_function.Evaluate(parameters, result, jacs);
109   for (int i = 0; i < kTestCostFunctionSize; i++) {
110     EXPECT_DOUBLE_EQ((i + 2) * (v1[i] - v2[i]) + i * 7, result[i]);
111   }
112 
113   for (int i = 0; i < kTestCostFunctionSize; i++) {
114     for (int j = 0; j < kTestCostFunctionSize; j++) {
115       double actual = jac[i * kTestCostFunctionSize + j];
116       if (i != j) {
117         EXPECT_DOUBLE_EQ(0, actual);
118       } else {
119         EXPECT_DOUBLE_EQ(i + 2, actual);
120       }
121     }
122   }
123 }
124 
125 }  // namespace internal
126 }  // namespace ceres
127