// 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: keir@google.com (Keir Mierle)

//

// A dense matrix implemented under the SparseMatrix interface.

#ifndef CERES_INTERNAL_DENSE_SPARSE_MATRIX_H_

#define CERES_INTERNAL_DENSE_SPARSE_MATRIX_H_

#include "ceres/sparse_matrix.h"

#include "ceres/internal/eigen.h"

#include "ceres/internal/macros.h"

#include "ceres/internal/scoped_ptr.h"

#include "ceres/types.h"

namespace ceres {

namespace internal {

class TripletSparseMatrix;

class DenseSparseMatrix : public SparseMatrix {

 public:

  // Build a matrix with the same content as the TripletSparseMatrix

  // m. This assumes that m does not have any repeated entries.

  explicit DenseSparseMatrix(const TripletSparseMatrix& m);

  explicit DenseSparseMatrix(const ColMajorMatrix& m);

  DenseSparseMatrix(int num_rows, int num_cols);

  DenseSparseMatrix(int num_rows, int num_cols, bool reserve_diagonal);

  virtual ~DenseSparseMatrix() {}

  // SparseMatrix interface.

  virtual void SetZero();

  virtual void RightMultiply(const double* x, double* y) const;

  virtual void LeftMultiply(const double* x, double* y) const;

  virtual void SquaredColumnNorm(double* x) const;

  virtual void ScaleColumns(const double* scale);

  virtual void ToDenseMatrix(Matrix* dense_matrix) const;

  virtual void ToTextFile(FILE* file) const;

  virtual int num_rows() const;

  virtual int num_cols() const;

  virtual int num_nonzeros() const;

  virtual const double* values() const { return m_.data(); }

  virtual double* mutable_values() { return m_.data(); }

  ConstColMajorMatrixRef matrix() const;

  ColMajorMatrixRef mutable_matrix();

  // Only one diagonal can be appended at a time. The diagonal is appended to

  // as a new set of rows, e.g.

  //

  // Original matrix:

  //

  //   x x x

  //   x x x

  //   x x x

  //

  // After append diagonal (1, 2, 3):

  //

  //   x x x

  //   x x x

  //   x x x

  //   1 0 0

  //   0 2 0

  //   0 0 3

  //

  // Calling RemoveDiagonal removes the block. It is a fatal error to append a

  // diagonal to a matrix that already has an appended diagonal, and it is also

  // a fatal error to remove a diagonal from a matrix that has none.

  void AppendDiagonal(double *d);

  void RemoveDiagonal();

 private:

  ColMajorMatrix m_;

  bool has_diagonal_appended_;

  bool has_diagonal_reserved_;

};

}  // namespace internal

}  // namespace ceres

#endif  // CERES_INTERNAL_DENSE_SPARSE_MATRIX_H_