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: keir@google.com (Keir Mierle)
30
31#ifndef CERES_INTERNAL_CGNR_SOLVER_H_
32#define CERES_INTERNAL_CGNR_SOLVER_H_
33
34#include "ceres/internal/scoped_ptr.h"
35#include "ceres/linear_solver.h"
36
37namespace ceres {
38namespace internal {
39
40class Preconditioner;
41
42class BlockJacobiPreconditioner;
43
44// A conjugate gradients on the normal equations solver. This directly solves
45// for the solution to
46//
47//   (A^T A + D^T D)x = A^T b
48//
49// as required for solving for x in the least squares sense. Currently only
50// block diagonal preconditioning is supported.
51class CgnrSolver : public BlockSparseMatrixSolver {
52 public:
53  explicit CgnrSolver(const LinearSolver::Options& options);
54  virtual Summary SolveImpl(
55      BlockSparseMatrix* A,
56      const double* b,
57      const LinearSolver::PerSolveOptions& per_solve_options,
58      double* x);
59
60 private:
61  const LinearSolver::Options options_;
62  scoped_ptr<Preconditioner> preconditioner_;
63  CERES_DISALLOW_COPY_AND_ASSIGN(CgnrSolver);
64};
65
66}  // namespace internal
67}  // namespace ceres
68
69#endif  // CERES_INTERNAL_CGNR_SOLVER_H_
70