1// Ceres Solver - A fast non-linear least squares minimizer
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29// Author: keir@google.com (Keir Mierle)
30//
31// A jacobian writer that writes to dense Eigen matrices.
32
33#ifndef CERES_INTERNAL_DENSE_JACOBIAN_WRITER_H_
34#define CERES_INTERNAL_DENSE_JACOBIAN_WRITER_H_
35
36#include "ceres/casts.h"
37#include "ceres/dense_sparse_matrix.h"
38#include "ceres/parameter_block.h"
39#include "ceres/program.h"
40#include "ceres/residual_block.h"
41#include "ceres/scratch_evaluate_preparer.h"
42#include "ceres/internal/eigen.h"
43
44namespace ceres {
45namespace internal {
46
47class DenseJacobianWriter {
48 public:
49  DenseJacobianWriter(Evaluator::Options /* ignored */,
50                      Program* program)
51    : program_(program) {
52  }
53
54  // JacobianWriter interface.
55
56  // Since the dense matrix has different layout than that assumed by the cost
57  // functions, use scratch space to store the jacobians temporarily then copy
58  // them over to the larger jacobian later.
59  ScratchEvaluatePreparer* CreateEvaluatePreparers(int num_threads) {
60    return ScratchEvaluatePreparer::Create(*program_, num_threads);
61  }
62
63  SparseMatrix* CreateJacobian() const {
64    return new DenseSparseMatrix(program_->NumResiduals(),
65                                 program_->NumEffectiveParameters(),
66                                 true);
67  }
68
69  void Write(int residual_id,
70             int residual_offset,
71             double **jacobians,
72             SparseMatrix* jacobian) {
73    DenseSparseMatrix* dense_jacobian;
74    if (jacobian != NULL) {
75      dense_jacobian = down_cast<DenseSparseMatrix*>(jacobian);
76    }
77    const ResidualBlock* residual_block =
78        program_->residual_blocks()[residual_id];
79    int num_parameter_blocks = residual_block->NumParameterBlocks();
80    int num_residuals = residual_block->NumResiduals();
81
82    // Now copy the jacobians for each parameter into the dense jacobian matrix.
83    for (int j = 0; j < num_parameter_blocks; ++j) {
84      ParameterBlock* parameter_block = residual_block->parameter_blocks()[j];
85
86      // If the parameter block is fixed, then there is nothing to do.
87      if (parameter_block->IsConstant()) {
88        continue;
89      }
90
91      const int parameter_block_size = parameter_block->LocalSize();
92      ConstMatrixRef parameter_jacobian(jacobians[j],
93                                        num_residuals,
94                                        parameter_block_size);
95
96      dense_jacobian->mutable_matrix().block(
97          residual_offset,
98          parameter_block->delta_offset(),
99          num_residuals,
100          parameter_block_size) = parameter_jacobian;
101    }
102  }
103
104 private:
105  Program* program_;
106};
107
108}  // namespace internal
109}  // namespace ceres
110
111#endif  // CERES_INTERNAL_DENSE_JACOBIAN_WRITER_H_
112