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

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

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

//

// Implementation of the SparseMatrix interface for block sparse

// matrices.

#ifndef CERES_INTERNAL_BLOCK_SPARSE_MATRIX_H_

#define CERES_INTERNAL_BLOCK_SPARSE_MATRIX_H_

#include "ceres/block_structure.h"

#include "ceres/sparse_matrix.h"

#include "ceres/internal/eigen.h"

#include "ceres/internal/macros.h"

#include "ceres/internal/scoped_ptr.h"

namespace ceres {

namespace internal {

class TripletSparseMatrix;

// This class implements the SparseMatrix interface for storing and

// manipulating block sparse matrices. The block structure is stored

// in the CompressedRowBlockStructure object and one is needed to

// initialize the matrix. For details on how the blocks structure of

// the matrix is stored please see the documentation

//

//   internal/ceres/block_structure.h

//

class BlockSparseMatrix : public SparseMatrix {

 public:

  // Construct a block sparse matrix with a fully initialized

  // CompressedRowBlockStructure objected. The matrix takes over

  // ownership of this object and destroys it upon destruction.

  //

  // TODO(sameeragarwal): Add a function which will validate legal

  // CompressedRowBlockStructure objects.

  explicit BlockSparseMatrix(CompressedRowBlockStructure* block_structure);

  BlockSparseMatrix();

  virtual ~BlockSparseMatrix();

  // Implementation of 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 { return num_rows_;     }

  virtual int num_cols()         const { return num_cols_;     }

  virtual int num_nonzeros()     const { return num_nonzeros_; }

  virtual const double* values() const { return values_.get(); }

  virtual double* mutable_values()     { return values_.get(); }

  void ToTripletSparseMatrix(TripletSparseMatrix* matrix) const;

  const CompressedRowBlockStructure* block_structure() const;

  // Append the contents of m to the bottom of this matrix. m must

  // have the same column blocks structure as this matrix.

  void AppendRows(const BlockSparseMatrix& m);

  // Delete the bottom delta_rows_blocks.

  void DeleteRowBlocks(int delta_row_blocks);

  static BlockSparseMatrix* CreateDiagonalMatrix(

      const double* diagonal,

      const std::vector<Block>& column_blocks);

  struct RandomMatrixOptions {

    RandomMatrixOptions()

        : num_row_blocks(0),

          min_row_block_size(0),

          max_row_block_size(0),

          num_col_blocks(0),

          min_col_block_size(0),

          max_col_block_size(0),

          block_density(0.0) {

    }

    int num_row_blocks;

    int min_row_block_size;

    int max_row_block_size;

    int num_col_blocks;

    int min_col_block_size;

    int max_col_block_size;

    // 0 < block_density <= 1 is the probability of a block being

    // present in the matrix. A given random matrix will not have

    // precisely this density.

    double block_density;

  };

  // Create a random BlockSparseMatrix whose entries are normally

  // distributed and whose structure is determined by

  // RandomMatrixOptions.

  //

  // Caller owns the result.

  static BlockSparseMatrix* CreateRandomMatrix(

      const RandomMatrixOptions& options);

 private:

  int num_rows_;

  int num_cols_;

  int num_nonzeros_;

  int max_num_nonzeros_;

  scoped_array<double> values_;

  scoped_ptr<CompressedRowBlockStructure> block_structure_;

  CERES_DISALLOW_COPY_AND_ASSIGN(BlockSparseMatrix);

};

}  // namespace internal

}  // namespace ceres

#endif  // CERES_INTERNAL_BLOCK_SPARSE_MATRIX_H_