// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

//

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// modification, are permitted provided that the following conditions are met:

//

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//   this list of conditions and the following disclaimer.

// * Redistributions in binary form must reproduce the above copyright notice,

//   this list of conditions and the following disclaimer in the documentation

//   and/or other materials provided with the distribution.

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//   used to endorse or promote products derived from this software without

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//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

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// Author: sameragarwal@google.com (Sameer Agarwal)

#ifndef CERES_INTERNAL_PREPROCESSOR_H_

#define CERES_INTERNAL_PREPROCESSOR_H_

#include <string>

#include <vector>

#include "ceres/coordinate_descent_minimizer.h"

#include "ceres/evaluator.h"

#include "ceres/internal/eigen.h"

#include "ceres/internal/port.h"

#include "ceres/internal/scoped_ptr.h"

#include "ceres/iteration_callback.h"

#include "ceres/linear_solver.h"

#include "ceres/minimizer.h"

#include "ceres/problem_impl.h"

#include "ceres/program.h"

#include "ceres/solver.h"

namespace ceres {

namespace internal {

struct PreprocessedProblem;

// Given a Problem object and a Solver::Options object indicating the

// configuration of the solver, the job of the Preprocessor is to

// analyze the Problem and perform the setup needed to solve it using

// the desired Minimization algorithm. The setup involves removing

// redundancies in the input problem (inactive parameter and residual

// blocks), finding fill reducing orderings as needed, configuring and

// creating various objects needed by the Minimizer to solve the

// problem such as an evaluator, a linear solver etc.

//

// Each Minimizer (LineSearchMinimizer and TrustRegionMinimizer) comes

// with a corresponding Preprocessor (LineSearchPreprocessor and

// TrustRegionPreprocessor) that knows about its needs and performs

// the preprocessing needed.

//

// The output of the Preprocessor is stored in a PreprocessedProblem

// object.

class Preprocessor {

 public:

  // Factory.

  static Preprocessor* Create(MinimizerType minimizer_type);

  virtual ~Preprocessor();

  virtual bool Preprocess(const Solver::Options& options,

                          ProblemImpl* problem,

                          PreprocessedProblem* pp) = 0;

};

// A PreprocessedProblem is the result of running the Preprocessor on

// a Problem and Solver::Options object.

struct PreprocessedProblem {

  PreprocessedProblem()

      : fixed_cost(0.0) {

  }

  std::string error;

  Solver::Options options;

  LinearSolver::Options linear_solver_options;

  Evaluator::Options evaluator_options;

  Minimizer::Options minimizer_options;

  ProblemImpl* problem;

  scoped_ptr<ProblemImpl> gradient_checking_problem;

  scoped_ptr<Program> reduced_program;

  scoped_ptr<LinearSolver> linear_solver;

  scoped_ptr<IterationCallback> logging_callback;

  scoped_ptr<IterationCallback> state_updating_callback;

  shared_ptr<Evaluator> evaluator;

  shared_ptr<CoordinateDescentMinimizer> inner_iteration_minimizer;

  std::vector<double*> removed_parameter_blocks;

  Vector reduced_parameters;

  double fixed_cost;

};

// Common functions used by various preprocessors.

// If OpenMP support is not available and user has requested more than

// one thread, then set the *_num_threads options as needed to 1.

void ChangeNumThreadsIfNeeded(Solver::Options* options);

// Extract the effective parameter vector from the preprocessed

// problem and setup bits of the Minimizer::Options object that are

// common to all Preprocessors.

void SetupCommonMinimizerOptions(PreprocessedProblem* pp);

}  // namespace internal

}  // namespace ceres

#endif  // CERES_INTERNAL_PREPROCESSOR_H_