1 // Ceres Solver - A fast non-linear least squares minimizer
2 // Copyright 2015 Google Inc. All rights reserved.
3 // http://ceres-solver.org/
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29 // Author: sameeragarwal@google.com (Sameer Agarwal)
31 #ifndef CERES_INTERNAL_COORDINATE_DESCENT_MINIMIZER_H_
32 #define CERES_INTERNAL_COORDINATE_DESCENT_MINIMIZER_H_
37 #include "ceres/evaluator.h"
38 #include "ceres/minimizer.h"
39 #include "ceres/problem_impl.h"
40 #include "ceres/solver.h"
48 // Given a Program, and a ParameterBlockOrdering which partitions
49 // (non-exhaustively) the Hessian matrix into independent sets,
50 // perform coordinate descent on the parameter blocks in the
51 // ordering. The independent set structure allows for all parameter
52 // blocks in the same independent set to be optimized in parallel, and
53 // the order of the independent set determines the order in which the
54 // parameter block groups are optimized.
56 // The minimizer assumes that none of the parameter blocks in the
57 // program are constant.
58 class CoordinateDescentMinimizer : public Minimizer {
60 bool Init(const Program& program,
61 const ProblemImpl::ParameterMap& parameter_map,
62 const ParameterBlockOrdering& ordering,
65 // Minimizer interface.
66 virtual ~CoordinateDescentMinimizer();
67 virtual void Minimize(const Minimizer::Options& options,
69 Solver::Summary* summary);
71 // Verify that each group in the ordering forms an independent set.
72 static bool IsOrderingValid(const Program& program,
73 const ParameterBlockOrdering& ordering,
74 std::string* message);
76 // Find a recursive decomposition of the Hessian matrix as a set
77 // of independent sets of decreasing size and invert it. This
78 // seems to work better in practice, i.e., Cameras before
80 static ParameterBlockOrdering* CreateOrdering(const Program& program);
83 void Solve(Program* program,
84 LinearSolver* linear_solver,
86 Solver::Summary* summary);
88 std::vector<ParameterBlock*> parameter_blocks_;
89 std::vector<std::vector<ResidualBlock*> > residual_blocks_;
90 // The optimization is performed in rounds. In each round all the
91 // parameter blocks that form one independent set are optimized in
92 // parallel. This array, marks the boundaries of the independent
93 // sets in parameter_blocks_.
94 std::vector<int> independent_set_offsets_;
96 Evaluator::Options evaluator_options_;
99 } // namespace internal
102 #endif // CERES_INTERNAL_COORDINATE_DESCENT_MINIMIZER_H_