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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: 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 
43 namespace ceres {
44 
45 // This class allows you to apply different conditioning to the residual
46 // values of a wrapped cost function. An example where this is useful is
47 // where you have an existing cost function that produces N values, but you
48 // want the total cost to be something other than just the sum of these
49 // squared values - maybe you want to apply a different scaling to some
50 // values, to change their contribution to the cost.
51 //
52 // Usage:
53 //
54 //   // my_cost_function produces N residuals
55 //   CostFunction* my_cost_function = ...
56 //   CHECK_EQ(N, my_cost_function->num_residuals());
57 //   vector<CostFunction*> conditioners;
58 //
59 //   // Make N 1x1 cost functions (1 parameter, 1 residual)
60 //   CostFunction* f_1 = ...
61 //   conditioners.push_back(f_1);
62 //   ...
63 //   CostFunction* f_N = ...
64 //   conditioners.push_back(f_N);
65 //   ConditionedCostFunction* ccf =
66 //     new ConditionedCostFunction(my_cost_function, conditioners);
67 //
68 // Now ccf's residual i (i=0..N-1) will be passed though the i'th conditioner.
69 //
70 //   ccf_residual[i] = f_i(my_cost_function_residual[i])
71 //
72 // and the Jacobian will be affected appropriately.
73 class ConditionedCostFunction : public CostFunction {
74  public:
75   // Builds a cost function based on a wrapped cost function, and a
76   // per-residual conditioner. Takes ownership of all of the wrapped cost
77   // functions, or not, depending on the ownership parameter. Conditioners
78   // may be NULL, in which case the corresponding residual is not modified.
79   ConditionedCostFunction(CostFunction* wrapped_cost_function,
80                           const vector<CostFunction*>& conditioners,
81                           Ownership ownership);
82   virtual ~ConditionedCostFunction();
83 
84   virtual bool Evaluate(double const* const* parameters,
85                         double* residuals,
86                         double** jacobians) const;
87 
88  private:
89   internal::scoped_ptr<CostFunction> wrapped_cost_function_;
90   vector<CostFunction*> conditioners_;
91   Ownership ownership_;
92 };
93 
94 }  // namespace ceres
95 
96 
97 #endif  // CERES_PUBLIC_CONDITIONED_COST_FUNCTION_H_
98