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//
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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
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20// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
21// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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28//
29// Author: sameeragarwal@google.com (Sameer Agarwal)
30
31#ifndef CERES_INTERNAL_LINE_SEARCH_DIRECTION_H_
32#define CERES_INTERNAL_LINE_SEARCH_DIRECTION_H_
33
34#include "ceres/internal/eigen.h"
35#include "ceres/line_search_minimizer.h"
36#include "ceres/types.h"
37
38namespace ceres {
39namespace internal {
40
41class LineSearchDirection {
42 public:
43  struct Options {
44    Options()
45        : num_parameters(0),
46          type(LBFGS),
47          nonlinear_conjugate_gradient_type(FLETCHER_REEVES),
48          function_tolerance(1e-12),
49          max_lbfgs_rank(20),
50          use_approximate_eigenvalue_bfgs_scaling(true) {
51    }
52
53    int num_parameters;
54    LineSearchDirectionType type;
55    NonlinearConjugateGradientType nonlinear_conjugate_gradient_type;
56    double function_tolerance;
57    int max_lbfgs_rank;
58    bool use_approximate_eigenvalue_bfgs_scaling;
59  };
60
61  static LineSearchDirection* Create(const Options& options);
62
63  virtual ~LineSearchDirection() {}
64  virtual bool NextDirection(const LineSearchMinimizer::State& previous,
65                             const LineSearchMinimizer::State& current,
66                             Vector* search_direction) = 0;
67};
68
69}  // namespace internal
70}  // namespace ceres
71
72#endif  // CERES_INTERNAL_LINE_SEARCH_DIRECTION_H_
73