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:
7//
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9//   this list of conditions and the following disclaimer.
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11//   this list of conditions and the following disclaimer in the documentation
12//   and/or other materials provided with the distribution.
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14//   used to endorse or promote products derived from this software without
15//   specific prior written permission.
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_TRIPLET_SPARSE_MATRIX_H_
32#define CERES_INTERNAL_TRIPLET_SPARSE_MATRIX_H_
33
34#include "ceres/sparse_matrix.h"
35#include "ceres/internal/eigen.h"
36#include "ceres/internal/scoped_ptr.h"
37#include "ceres/types.h"
38
39namespace ceres {
40namespace internal {
41
42// An implementation of the SparseMatrix interface to store and
43// manipulate sparse matrices in triplet (i,j,s) form.  This object is
44// inspired by the design of the cholmod_triplet struct used in the
45// SuiteSparse package and is memory layout compatible with it.
46class TripletSparseMatrix : public SparseMatrix {
47 public:
48  TripletSparseMatrix();
49  TripletSparseMatrix(int num_rows, int num_cols, int max_num_nonzeros);
50  explicit TripletSparseMatrix(const TripletSparseMatrix& orig);
51
52  TripletSparseMatrix& operator=(const TripletSparseMatrix& rhs);
53
54  ~TripletSparseMatrix();
55
56  // Implementation of the SparseMatrix interface.
57  virtual void SetZero();
58  virtual void RightMultiply(const double* x, double* y) const;
59  virtual void LeftMultiply(const double* x, double* y) const;
60  virtual void SquaredColumnNorm(double* x) const;
61  virtual void ScaleColumns(const double* scale);
62  virtual void ToDenseMatrix(Matrix* dense_matrix) const;
63  virtual void ToTextFile(FILE* file) const;
64  virtual int num_rows()        const { return num_rows_;     }
65  virtual int num_cols()        const { return num_cols_;     }
66  virtual int num_nonzeros()    const { return num_nonzeros_; }
67  virtual const double* values()  const { return values_.get(); }
68  virtual double* mutable_values()      { return values_.get(); }
69  virtual void set_num_nonzeros(int num_nonzeros);
70
71  // Increase max_num_nonzeros and correspondingly increase the size
72  // of rows_, cols_ and values_. If new_max_num_nonzeros is smaller
73  // than max_num_nonzeros_, then num_non_zeros should be less than or
74  // equal to new_max_num_nonzeros, otherwise data loss is possible
75  // and the method crashes.
76  void Reserve(int new_max_num_nonzeros);
77
78  // Append the matrix B at the bottom of this matrix. B should have
79  // the same number of columns as num_cols_.
80  void AppendRows(const TripletSparseMatrix& B);
81
82  // Append the matrix B at the right of this matrix. B should have
83  // the same number of rows as num_rows_;
84  void AppendCols(const TripletSparseMatrix& B);
85
86  // Resize the matrix. Entries which fall outside the new matrix
87  // bounds are dropped and the num_non_zeros changed accordingly.
88  void Resize(int new_num_rows, int new_num_cols);
89
90  int max_num_nonzeros() const { return max_num_nonzeros_; }
91  const int* rows()      const { return rows_.get();       }
92  const int* cols()      const { return cols_.get();       }
93  int* mutable_rows()          { return rows_.get();       }
94  int* mutable_cols()          { return cols_.get();       }
95
96  // Returns true if the entries of the matrix obey the row, column,
97  // and column size bounds and false otherwise.
98  bool AllTripletsWithinBounds() const;
99
100  bool IsValid() const { return AllTripletsWithinBounds(); }
101
102  // Build a sparse diagonal matrix of size num_rows x num_rows from
103  // the array values. Entries of the values array are copied into the
104  // sparse matrix.
105  static TripletSparseMatrix* CreateSparseDiagonalMatrix(const double* values,
106                                                         int num_rows);
107
108 private:
109  void AllocateMemory();
110  void CopyData(const TripletSparseMatrix& orig);
111
112  int num_rows_;
113  int num_cols_;
114  int max_num_nonzeros_;
115  int num_nonzeros_;
116
117  // The data is stored as three arrays. For each i, values_[i] is
118  // stored at the location (rows_[i], cols_[i]). If the there are
119  // multiple entries with the same (rows_[i], cols_[i]), the values_
120  // entries corresponding to them are summed up.
121  scoped_array<int> rows_;
122  scoped_array<int> cols_;
123  scoped_array<double> values_;
124};
125
126}  // namespace internal
127}  // namespace ceres
128
129#endif  // CERES_INTERNAL_TRIPLET_SPARSE_MATRIX_H__
130