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_SPARSE_MATRIX_H_
32 #define CERES_INTERNAL_BLOCK_RANDOM_ACCESS_SPARSE_MATRIX_H_
33 
34 #include <set>
35 #include <vector>
36 #include <utility>
37 #include "ceres/mutex.h"
38 #include "ceres/block_random_access_matrix.h"
39 #include "ceres/collections_port.h"
40 #include "ceres/triplet_sparse_matrix.h"
41 #include "ceres/integral_types.h"
42 #include "ceres/internal/macros.h"
43 #include "ceres/internal/port.h"
44 #include "ceres/internal/scoped_ptr.h"
45 #include "ceres/types.h"
46 
47 namespace ceres {
48 namespace internal {
49 
50 // A thread safe square block sparse implementation of
51 // BlockRandomAccessMatrix. Internally a TripletSparseMatrix is used
52 // for doing the actual storage. This class augments this matrix with
53 // an unordered_map that allows random read/write access.
54 class BlockRandomAccessSparseMatrix : public BlockRandomAccessMatrix {
55  public:
56   // blocks is an array of block sizes. block_pairs is a set of
57   // <row_block_id, col_block_id> pairs to identify the non-zero cells
58   // of this matrix.
59   BlockRandomAccessSparseMatrix(const vector<int>& blocks,
60                                 const set<pair<int, int> >& block_pairs);
61 
62   // The destructor is not thread safe. It assumes that no one is
63   // modifying any cells when the matrix is being destroyed.
64   virtual ~BlockRandomAccessSparseMatrix();
65 
66   // BlockRandomAccessMatrix Interface.
67   virtual CellInfo* GetCell(int row_block_id,
68                             int col_block_id,
69                             int* row,
70                             int* col,
71                             int* row_stride,
72                             int* col_stride);
73 
74   // This is not a thread safe method, it assumes that no cell is
75   // locked.
76   virtual void SetZero();
77 
78   // Since the matrix is square, num_rows() == num_cols().
num_rows()79   virtual int num_rows() const { return tsm_->num_rows(); }
num_cols()80   virtual int num_cols() const { return tsm_->num_cols(); }
81 
82   // Access to the underlying matrix object.
matrix()83   const TripletSparseMatrix* matrix() const { return tsm_.get(); }
mutable_matrix()84   TripletSparseMatrix* mutable_matrix() { return tsm_.get(); }
85 
86  private:
IntPairToLong(int a,int b)87   int64 IntPairToLong(int a, int b) {
88     return a * kMaxRowBlocks + b;
89   }
90 
91   const int64 kMaxRowBlocks;
92   // row/column block sizes.
93   const vector<int> blocks_;
94 
95   // A mapping from <row_block_id, col_block_id> to the position in
96   // the values array of tsm_ where the block is stored.
97   typedef HashMap<long int, CellInfo* > LayoutType;
98   LayoutType layout_;
99 
100   // The underlying matrix object which actually stores the cells.
101   scoped_ptr<TripletSparseMatrix> tsm_;
102 
103   friend class BlockRandomAccessSparseMatrixTest;
104   CERES_DISALLOW_COPY_AND_ASSIGN(BlockRandomAccessSparseMatrix);
105 };
106 
107 }  // namespace internal
108 }  // namespace ceres
109 
110 #endif  // CERES_INTERNAL_BLOCK_RANDOM_ACCESS_SPARSE_MATRIX_H_
111