// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2013 Google Inc. All rights reserved.
// http://code.google.com/p/ceres-solver/
//
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// modification, are permitted provided that the following conditions are met:
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// Author: sameeragarwal@google.com (Sameer Agarwal)

#ifndef CERES_INTERNAL_COVARIANCE_IMPL_H_
#define CERES_INTERNAL_COVARIANCE_IMPL_H_

#include <map>
#include <set>
#include <utility>
#include <vector>
#include "ceres/covariance.h"
#include "ceres/internal/scoped_ptr.h"
#include "ceres/problem_impl.h"
#include "ceres/suitesparse.h"

namespace ceres {

namespace internal {

class CompressedRowSparseMatrix;

class CovarianceImpl {
 public:
  explicit CovarianceImpl(const Covariance::Options& options);
  ~CovarianceImpl();

  bool Compute(
      const vector<pair<const double*, const double*> >& covariance_blocks,
      ProblemImpl* problem);

  bool GetCovarianceBlock(const double* parameter_block1,
                          const double* parameter_block2,
                          double* covariance_block) const;

  bool ComputeCovarianceSparsity(
      const vector<pair<const double*, const double*> >& covariance_blocks,
      ProblemImpl* problem);

  bool ComputeCovarianceValues();
  bool ComputeCovarianceValuesUsingDenseSVD();
  bool ComputeCovarianceValuesUsingSuiteSparseQR();
  bool ComputeCovarianceValuesUsingEigenSparseQR();

  const CompressedRowSparseMatrix* covariance_matrix() const {
    return covariance_matrix_.get();
  }

 private:
  ProblemImpl* problem_;
  Covariance::Options options_;
  Problem::EvaluateOptions evaluate_options_;
  bool is_computed_;
  bool is_valid_;
  map<const double*, int> parameter_block_to_row_index_;
  set<const double*> constant_parameter_blocks_;
  scoped_ptr<CompressedRowSparseMatrix> covariance_matrix_;
};

}  // namespace internal
}  // namespace ceres

#endif  // CERES_INTERNAL_COVARIANCE_IMPL_H_
