block_structure.h revision 0ae28bd5885b5daa526898fcf7c323dc2c3e1963 
1// Ceres Solver - A fast non-linear least squares minimizer
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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
45namespace ceres {
46namespace internal {
47
48class BlockStructureProto;
49
50typedef int16 BlockSize;
51
52struct Block {
53  Block() : size(-1), position(-1) {}
54  Block(int size_, int position_) : size(size_), position(position_) {}
55
56  BlockSize size;
57  int position;  // Position along the row/column.
58};
59
60struct Cell {
61  Cell() : block_id(-1), position(-1) {}
62  Cell(int block_id_, int position_)
63      : block_id(block_id_), position(position_) {}
64
65  // Column or row block id as the case maybe.
66  int block_id;
67  // Where in the values array of the jacobian is this cell located.
68  int position;
69};
70
71// Order cell by their block_id;
72bool CellLessThan(const Cell& lhs, const Cell& rhs);
73
74struct CompressedList {
75  Block block;
76  vector<Cell> cells;
77};
78
79typedef CompressedList CompressedRow;
80typedef CompressedList CompressedColumn;
81
82struct CompressedRowBlockStructure {
83  vector<Block> cols;
84  vector<CompressedRow> rows;
85};
86
87struct CompressedColumnBlockStructure {
88  vector<Block> rows;
89  vector<CompressedColumn> cols;
90};
91
92// Deserialize the given block structure proto to the given block structure.
93// Destroys previous contents of block_structure.
94void ProtoToBlockStructure(const BlockStructureProto &proto,
95                           CompressedRowBlockStructure *block_structure);
96
97// Serialize the given block structure to the given proto. Destroys previous
98// contents of proto.
99void BlockStructureToProto(const CompressedRowBlockStructure &block_structure,
100                           BlockStructureProto *proto);
101
102}  // namespace internal
103}  // namespace ceres
104
105#endif  // CERES_INTERNAL_BLOCK_STRUCTURE_H_
106