1 // Ceres Solver - A fast non-linear least squares minimizer
2 // Copyright 2012 Google Inc. All rights reserved.
3 // http://code.google.com/p/ceres-solver/
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29 // Author: sameeragarwal@google.com (Sameer Agarwal)
30 
31 #ifndef CERES_PUBLIC_CRS_MATRIX_H_
32 #define CERES_PUBLIC_CRS_MATRIX_H_
33 
34 #include <vector>
35 #include "ceres/internal/port.h"
36 #include "ceres/internal/disable_warnings.h"
37 
38 namespace ceres {
39 
40 // A compressed row sparse matrix used primarily for communicating the
41 // Jacobian matrix to the user.
42 struct CERES_EXPORT CRSMatrix {
CRSMatrixCRSMatrix43   CRSMatrix() : num_rows(0), num_cols(0) {}
44 
45   int num_rows;
46   int num_cols;
47 
48   // A compressed row matrix stores its contents in three arrays,
49   // rows, cols and values.
50   //
51   // rows is a num_rows + 1 sized array that points into the cols and
52   // values array. For each row i:
53   //
54   // cols[rows[i]] ... cols[rows[i + 1] - 1] are the indices of the
55   // non-zero columns of row i.
56   //
57   // values[rows[i]] .. values[rows[i + 1] - 1] are the values of the
58   // corresponding entries.
59   //
60   // cols and values contain as many entries as there are non-zeros in
61   // the matrix.
62   //
63   // e.g, consider the 3x4 sparse matrix
64   //
65   //  [ 0 10  0  4 ]
66   //  [ 0  2 -3  2 ]
67   //  [ 1  2  0  0 ]
68   //
69   // The three arrays will be:
70   //
71   //
72   //            -row0-  ---row1---  -row2-
73   //  rows   = [ 0,      2,          5,     7]
74   //  cols   = [ 1,  3,  1,  2,  3,  0,  1]
75   //  values = [10,  4,  2, -3,  2,  1,  2]
76 
77   vector<int> cols;
78   vector<int> rows;
79   vector<double> values;
80 };
81 
82 }  // namespace ceres
83 
84 #include "ceres/internal/reenable_warnings.h"
85 
86 #endif  // CERES_PUBLIC_CRS_MATRIX_H_
87