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//
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6// modification, are permitted provided that the following conditions are met:
7//
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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
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28//
29// Author: wjr@google.com (William Rucklidge)
30//
31// This file contains a cost function that can apply a transformation to
32// each residual value before they are square-summed.
33
34#ifndef CERES_PUBLIC_CONDITIONED_COST_FUNCTION_H_
35#define CERES_PUBLIC_CONDITIONED_COST_FUNCTION_H_
36
37#include <vector>
38
39#include "ceres/cost_function.h"
40#include "ceres/internal/scoped_ptr.h"
41#include "ceres/types.h"
42#include "ceres/internal/disable_warnings.h"
43
44namespace ceres {
45
46// This class allows you to apply different conditioning to the residual
47// values of a wrapped cost function. An example where this is useful is
48// where you have an existing cost function that produces N values, but you
49// want the total cost to be something other than just the sum of these
50// squared values - maybe you want to apply a different scaling to some
51// values, to change their contribution to the cost.
52//
53// Usage:
54//
55//   // my_cost_function produces N residuals
56//   CostFunction* my_cost_function = ...
57//   CHECK_EQ(N, my_cost_function->num_residuals());
58//   vector<CostFunction*> conditioners;
59//
60//   // Make N 1x1 cost functions (1 parameter, 1 residual)
61//   CostFunction* f_1 = ...
62//   conditioners.push_back(f_1);
63//   ...
64//   CostFunction* f_N = ...
65//   conditioners.push_back(f_N);
66//   ConditionedCostFunction* ccf =
67//     new ConditionedCostFunction(my_cost_function, conditioners);
68//
69// Now ccf's residual i (i=0..N-1) will be passed though the i'th conditioner.
70//
71//   ccf_residual[i] = f_i(my_cost_function_residual[i])
72//
73// and the Jacobian will be affected appropriately.
74class CERES_EXPORT ConditionedCostFunction : public CostFunction {
75 public:
76  // Builds a cost function based on a wrapped cost function, and a
77  // per-residual conditioner. Takes ownership of all of the wrapped cost
78  // functions, or not, depending on the ownership parameter. Conditioners
79  // may be NULL, in which case the corresponding residual is not modified.
80  ConditionedCostFunction(CostFunction* wrapped_cost_function,
81                          const vector<CostFunction*>& conditioners,
82                          Ownership ownership);
83  virtual ~ConditionedCostFunction();
84
85  virtual bool Evaluate(double const* const* parameters,
86                        double* residuals,
87                        double** jacobians) const;
88
89 private:
90  internal::scoped_ptr<CostFunction> wrapped_cost_function_;
91  vector<CostFunction*> conditioners_;
92  Ownership ownership_;
93};
94
95}  // namespace ceres
96
97#include "ceres/internal/reenable_warnings.h"
98
99#endif  // CERES_PUBLIC_CONDITIONED_COST_FUNCTION_H_
100