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

// Copyright 2015 Google Inc. All rights reserved.

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

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

#ifndef CERES_INTERNAL_LINEAR_LEAST_SQUARES_PROBLEMS_H_

#define CERES_INTERNAL_LINEAR_LEAST_SQUARES_PROBLEMS_H_

#include <string>

#include <vector>

#include "ceres/sparse_matrix.h"

#include "ceres/internal/port.h"

#include "ceres/internal/scoped_ptr.h"

namespace ceres {

namespace internal {

// Structure defining a linear least squares problem and if possible

// ground truth solutions. To be used by various LinearSolver tests.

struct LinearLeastSquaresProblem {

  LinearLeastSquaresProblem()

      : A(NULL), b(NULL), D(NULL), num_eliminate_blocks(0),

        x(NULL), x_D(NULL) {

  }

  scoped_ptr<SparseMatrix> A;

  scoped_array<double> b;

  scoped_array<double> D;

  // If using the schur eliminator then how many of the variable

  // blocks are e_type blocks.

  int num_eliminate_blocks;

  // Solution to min_x |Ax - b|^2

  scoped_array<double> x;

  // Solution to min_x |Ax - b|^2 + |Dx|^2

  scoped_array<double> x_D;

};

// Factories for linear least squares problem.

LinearLeastSquaresProblem* CreateLinearLeastSquaresProblemFromId(int id);

LinearLeastSquaresProblem* LinearLeastSquaresProblem0();

LinearLeastSquaresProblem* LinearLeastSquaresProblem1();

LinearLeastSquaresProblem* LinearLeastSquaresProblem2();

LinearLeastSquaresProblem* LinearLeastSquaresProblem3();

LinearLeastSquaresProblem* LinearLeastSquaresProblem4();

// Write the linear least squares problem to disk. The exact format

// depends on dump_format_type.

bool DumpLinearLeastSquaresProblem(const std::string& filename_base,

                                   DumpFormatType dump_format_type,

                                   const SparseMatrix* A,

                                   const double* D,

                                   const double* b,

                                   const double* x,

                                   int num_eliminate_blocks);

}  // namespace internal

}  // namespace ceres

#endif  // CERES_INTERNAL_LINEAR_LEAST_SQUARES_PROBLEMS_H_