internal/ceres/dynamic_compressed_row_jacobian_writer.cc

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