1 // Ceres Solver - A fast non-linear least squares minimizer
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29 // Author: sameeragarwal@google.com (Sameer Agarwal)
30 
31 #ifndef CERES_INTERNAL_BLOCK_RANDOM_ACCESS_DIAGONAL_MATRIX_H_
32 #define CERES_INTERNAL_BLOCK_RANDOM_ACCESS_DIAGONAL_MATRIX_H_
33 
34 #include <memory>
35 #include <set>
36 #include <utility>
37 #include <vector>
38 
39 #include "ceres/block_random_access_matrix.h"
40 #include "ceres/internal/port.h"
41 #include "ceres/triplet_sparse_matrix.h"
42 #include "ceres/types.h"
43 
44 namespace ceres {
45 namespace internal {
46 
47 // A thread safe block diagonal matrix implementation of
48 // BlockRandomAccessMatrix.
49 class BlockRandomAccessDiagonalMatrix : public BlockRandomAccessMatrix {
50  public:
51   // blocks is an array of block sizes.
52   explicit BlockRandomAccessDiagonalMatrix(const std::vector<int>& blocks);
53   BlockRandomAccessDiagonalMatrix(const BlockRandomAccessDiagonalMatrix&) = delete;
54   void operator=(const BlockRandomAccessDiagonalMatrix&) = delete;
55 
56   // The destructor is not thread safe. It assumes that no one is
57   // modifying any cells when the matrix is being destroyed.
58   virtual ~BlockRandomAccessDiagonalMatrix();
59 
60   // BlockRandomAccessMatrix Interface.
61   CellInfo* GetCell(int row_block_id,
62                     int col_block_id,
63                     int* row,
64                     int* col,
65                     int* row_stride,
66                     int* col_stride) final;
67 
68   // This is not a thread safe method, it assumes that no cell is
69   // locked.
70   void SetZero() final;
71 
72   // Invert the matrix assuming that each block is positive definite.
73   void Invert();
74 
75   // y += S * x
76   void RightMultiply(const double* x, double* y) const;
77 
78   // Since the matrix is square, num_rows() == num_cols().
num_rows()79   int num_rows() const final { return tsm_->num_rows(); }
num_cols()80   int num_cols() const final { return tsm_->num_cols(); }
81 
matrix()82   const TripletSparseMatrix* matrix() const { return tsm_.get(); }
mutable_matrix()83   TripletSparseMatrix* mutable_matrix() { return tsm_.get(); }
84 
85  private:
86   // row/column block sizes.
87   const std::vector<int> blocks_;
88   std::vector<CellInfo*> layout_;
89 
90   // The underlying matrix object which actually stores the cells.
91   std::unique_ptr<TripletSparseMatrix> tsm_;
92 
93   friend class BlockRandomAccessDiagonalMatrixTest;
94 };
95 
96 }  // namespace internal
97 }  // namespace ceres
98 
99 #endif  // CERES_INTERNAL_BLOCK_RANDOM_ACCESS_DIAGONAL_MATRIX_H_
100