1// Ceres Solver - A fast non-linear least squares minimizer
2// Copyright 2013 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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16//
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28//
29// Author: sameeragarwal@google.com (Sameer Agarwal)
30
31#include "ceres/block_random_access_diagonal_matrix.h"
32
33#include <algorithm>
34#include <set>
35#include <utility>
36#include <vector>
37#include "ceres/internal/port.h"
38#include "ceres/internal/scoped_ptr.h"
39#include "ceres/triplet_sparse_matrix.h"
40#include "ceres/types.h"
41#include "ceres/stl_util.h"
42#include "glog/logging.h"
43
44namespace ceres {
45namespace internal {
46
47BlockRandomAccessDiagonalMatrix::BlockRandomAccessDiagonalMatrix(
48    const vector<int>& blocks)
49    : blocks_(blocks) {
50  // Build the row/column layout vector and count the number of scalar
51  // rows/columns.
52  int num_cols = 0;
53  int num_nonzeros = 0;
54  vector<int> col_layout;
55  for (int i = 0; i < blocks_.size(); ++i) {
56    col_layout.push_back(num_cols);
57    num_cols += blocks_[i];
58    num_nonzeros += blocks_[i] * blocks_[i];
59  }
60
61  VLOG(1) << "Matrix Size [" << num_cols
62          << "," << num_cols
63          << "] " << num_nonzeros;
64
65  tsm_.reset(new TripletSparseMatrix(num_cols, num_cols, num_nonzeros));
66  tsm_->set_num_nonzeros(num_nonzeros);
67  int* rows = tsm_->mutable_rows();
68  int* cols = tsm_->mutable_cols();
69  double* values = tsm_->mutable_values();
70
71  int pos = 0;
72  for (int i = 0; i < blocks_.size(); ++i) {
73    const int block_size = blocks_[i];
74    layout_.push_back(new CellInfo(values + pos));
75    const int block_begin = col_layout[i];
76    for (int r = 0; r < block_size; ++r) {
77      for (int c = 0; c < block_size; ++c, ++pos) {
78        rows[pos] = block_begin + r;
79        cols[pos] = block_begin + c;
80      }
81    }
82  }
83}
84
85// Assume that the user does not hold any locks on any cell blocks
86// when they are calling SetZero.
87BlockRandomAccessDiagonalMatrix::~BlockRandomAccessDiagonalMatrix() {
88  STLDeleteContainerPointers(layout_.begin(), layout_.end());
89}
90
91CellInfo* BlockRandomAccessDiagonalMatrix::GetCell(int row_block_id,
92                                                   int col_block_id,
93                                                   int* row,
94                                                   int* col,
95                                                   int* row_stride,
96                                                   int* col_stride) {
97  if (row_block_id != col_block_id) {
98    return NULL;
99  }
100  const int stride = blocks_[row_block_id];
101
102  // Each cell is stored contiguously as its own little dense matrix.
103  *row = 0;
104  *col = 0;
105  *row_stride = stride;
106  *col_stride = stride;
107  return layout_[row_block_id];
108}
109
110// Assume that the user does not hold any locks on any cell blocks
111// when they are calling SetZero.
112void BlockRandomAccessDiagonalMatrix::SetZero() {
113  if (tsm_->num_nonzeros()) {
114    VectorRef(tsm_->mutable_values(),
115              tsm_->num_nonzeros()).setZero();
116  }
117}
118
119}  // namespace internal
120}  // namespace ceres
121