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/
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28 //
29 // Author: sameeragarwal@google.com (Sameer Agarwal)
30 //
31 // Block structure objects are used to carry information about the
32 // dense block structure of sparse matrices. The BlockSparseMatrix
33 // object uses the BlockStructure objects to keep track of the matrix
34 // structure and operate upon it. This allows us to use more cache
35 // friendly block oriented linear algebra operations on the matrix
36 // instead of accessing it one scalar entry at a time.
37 
38 #ifndef CERES_INTERNAL_BLOCK_STRUCTURE_H_
39 #define CERES_INTERNAL_BLOCK_STRUCTURE_H_
40 
41 #include <vector>
42 #include "ceres/internal/port.h"
43 #include "ceres/types.h"
44 
45 namespace ceres {
46 namespace internal {
47 
48 typedef int32 BlockSize;
49 
50 struct Block {
BlockBlock51   Block() : size(-1), position(-1) {}
BlockBlock52   Block(int size_, int position_) : size(size_), position(position_) {}
53 
54   BlockSize size;
55   int position;  // Position along the row/column.
56 };
57 
58 struct Cell {
CellCell59   Cell() : block_id(-1), position(-1) {}
CellCell60   Cell(int block_id_, int position_)
61       : block_id(block_id_), position(position_) {}
62 
63   // Column or row block id as the case maybe.
64   int block_id;
65   // Where in the values array of the jacobian is this cell located.
66   int position;
67 };
68 
69 // Order cell by their block_id;
70 bool CellLessThan(const Cell& lhs, const Cell& rhs);
71 
72 struct CompressedList {
73   Block block;
74   vector<Cell> cells;
75 };
76 
77 typedef CompressedList CompressedRow;
78 typedef CompressedList CompressedColumn;
79 
80 struct CompressedRowBlockStructure {
81   vector<Block> cols;
82   vector<CompressedRow> rows;
83 };
84 
85 struct CompressedColumnBlockStructure {
86   vector<Block> rows;
87   vector<CompressedColumn> cols;
88 };
89 
90 }  // namespace internal
91 }  // namespace ceres
92 
93 #endif  // CERES_INTERNAL_BLOCK_STRUCTURE_H_
94