1// Ceres Solver - A fast non-linear least squares minimizer
2// Copyright 2014 Google Inc. All rights reserved.
3// http://code.google.com/p/ceres-solver/
4//
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16//
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28//
29// Author: richie.stebbing@gmail.com (Richard Stebbing)
30
31#include "ceres/compressed_row_jacobian_writer.h"
32#include "ceres/dynamic_compressed_row_jacobian_writer.h"
33#include "ceres/casts.h"
34#include "ceres/dynamic_compressed_row_sparse_matrix.h"
35#include "ceres/parameter_block.h"
36#include "ceres/program.h"
37#include "ceres/residual_block.h"
38
39namespace ceres {
40namespace internal {
41
42ScratchEvaluatePreparer*
43DynamicCompressedRowJacobianWriter::CreateEvaluatePreparers(int num_threads) {
44  return ScratchEvaluatePreparer::Create(*program_, num_threads);
45}
46
47SparseMatrix* DynamicCompressedRowJacobianWriter::CreateJacobian() const {
48  // Initialize `jacobian` with zero number of `max_num_nonzeros`.
49  const int num_residuals = program_->NumResiduals();
50  const int num_effective_parameters = program_->NumEffectiveParameters();
51
52  DynamicCompressedRowSparseMatrix* jacobian =
53      new DynamicCompressedRowSparseMatrix(num_residuals,
54                                           num_effective_parameters,
55                                           0);
56
57  CompressedRowJacobianWriter::PopulateJacobianRowAndColumnBlockVectors(
58      program_, jacobian);
59
60  return jacobian;
61}
62
63void DynamicCompressedRowJacobianWriter::Write(int residual_id,
64                                               int residual_offset,
65                                               double **jacobians,
66                                               SparseMatrix* base_jacobian) {
67  DynamicCompressedRowSparseMatrix* jacobian =
68    down_cast<DynamicCompressedRowSparseMatrix*>(base_jacobian);
69
70  // Get the `residual_block` of interest.
71  const ResidualBlock* residual_block =
72      program_->residual_blocks()[residual_id];
73  const int num_residuals = residual_block->NumResiduals();
74
75  vector<pair<int, int> > evaluated_jacobian_blocks;
76  CompressedRowJacobianWriter::GetOrderedParameterBlocks(
77    program_, residual_id, &evaluated_jacobian_blocks);
78
79  // `residual_offset` is the residual row in the global jacobian.
80  // Empty the jacobian rows.
81  jacobian->ClearRows(residual_offset, num_residuals);
82
83  // Iterate over each parameter block.
84  for (int i = 0; i < evaluated_jacobian_blocks.size(); ++i) {
85    const ParameterBlock* parameter_block =
86        program_->parameter_blocks()[evaluated_jacobian_blocks[i].first];
87    const int parameter_block_jacobian_index =
88        evaluated_jacobian_blocks[i].second;
89    const int parameter_block_size = parameter_block->LocalSize();
90
91    // For each parameter block only insert its non-zero entries.
92    for (int r = 0; r < num_residuals; ++r) {
93      for (int c = 0; c < parameter_block_size; ++c) {
94        const double& v = jacobians[parameter_block_jacobian_index][
95            r * parameter_block_size + c];
96        // Only insert non-zero entries.
97        if (v != 0.0) {
98          jacobian->InsertEntry(
99            residual_offset + r, parameter_block->delta_offset() + c, v);
100        }
101      }
102    }
103  }
104}
105
106}  // namespace internal
107}  // namespace ceres
108