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/
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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 
37 namespace ceres {
38 namespace internal {
39 
40 class Preconditioner;
41 
42 class 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.
51 class 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