1// Ceres Solver - A fast non-linear least squares minimizer
2// Copyright 2010, 2011, 2012 Google Inc. All rights reserved.
3// http://code.google.com/p/ceres-solver/
4//
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6// modification, are permitted provided that the following conditions are met:
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12//   and/or other materials provided with the distribution.
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16//
17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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28//
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
47namespace ceres {
48namespace 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.
54class 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().
79  virtual int num_rows() const { return tsm_->num_rows(); }
80  virtual int num_cols() const { return tsm_->num_cols(); }
81
82  // Access to the underlying matrix object.
83  const TripletSparseMatrix* matrix() const { return tsm_.get(); }
84  TripletSparseMatrix* mutable_matrix() { return tsm_.get(); }
85
86 private:
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