| // Ceres Solver - A fast non-linear least squares minimizer | 
 | // Copyright 2022 Google Inc. All rights reserved. | 
 | // http://ceres-solver.org/ | 
 | // | 
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 | // | 
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 | // | 
 | // Author: keir@google.com (Keir Mierle) | 
 |  | 
 | #include "ceres/compressed_row_jacobian_writer.h" | 
 |  | 
 | #include <algorithm> | 
 | #include <iterator> | 
 | #include <memory> | 
 | #include <string> | 
 | #include <utility> | 
 | #include <vector> | 
 |  | 
 | #include "ceres/casts.h" | 
 | #include "ceres/compressed_row_sparse_matrix.h" | 
 | #include "ceres/parameter_block.h" | 
 | #include "ceres/program.h" | 
 | #include "ceres/residual_block.h" | 
 | #include "ceres/scratch_evaluate_preparer.h" | 
 |  | 
 | namespace ceres::internal { | 
 |  | 
 | using std::adjacent_find; | 
 | using std::make_pair; | 
 | using std::pair; | 
 | using std::vector; | 
 |  | 
 | void CompressedRowJacobianWriter::PopulateJacobianRowAndColumnBlockVectors( | 
 |     const Program* program, CompressedRowSparseMatrix* jacobian) { | 
 |   const vector<ParameterBlock*>& parameter_blocks = program->parameter_blocks(); | 
 |   vector<int>& col_blocks = *(jacobian->mutable_col_blocks()); | 
 |   col_blocks.resize(parameter_blocks.size()); | 
 |   for (int i = 0; i < parameter_blocks.size(); ++i) { | 
 |     col_blocks[i] = parameter_blocks[i]->TangentSize(); | 
 |   } | 
 |  | 
 |   const vector<ResidualBlock*>& residual_blocks = program->residual_blocks(); | 
 |   vector<int>& row_blocks = *(jacobian->mutable_row_blocks()); | 
 |   row_blocks.resize(residual_blocks.size()); | 
 |   for (int i = 0; i < residual_blocks.size(); ++i) { | 
 |     row_blocks[i] = residual_blocks[i]->NumResiduals(); | 
 |   } | 
 | } | 
 |  | 
 | void CompressedRowJacobianWriter::GetOrderedParameterBlocks( | 
 |     const Program* program, | 
 |     int residual_id, | 
 |     vector<pair<int, int>>* evaluated_jacobian_blocks) { | 
 |   const ResidualBlock* residual_block = program->residual_blocks()[residual_id]; | 
 |   const int num_parameter_blocks = residual_block->NumParameterBlocks(); | 
 |  | 
 |   for (int j = 0; j < num_parameter_blocks; ++j) { | 
 |     const ParameterBlock* parameter_block = | 
 |         residual_block->parameter_blocks()[j]; | 
 |     if (!parameter_block->IsConstant()) { | 
 |       evaluated_jacobian_blocks->push_back( | 
 |           make_pair(parameter_block->index(), j)); | 
 |     } | 
 |   } | 
 |   std::sort(evaluated_jacobian_blocks->begin(), | 
 |             evaluated_jacobian_blocks->end()); | 
 | } | 
 |  | 
 | std::unique_ptr<SparseMatrix> CompressedRowJacobianWriter::CreateJacobian() | 
 |     const { | 
 |   const vector<ResidualBlock*>& residual_blocks = program_->residual_blocks(); | 
 |  | 
 |   int total_num_residuals = program_->NumResiduals(); | 
 |   int total_num_effective_parameters = program_->NumEffectiveParameters(); | 
 |  | 
 |   // Count the number of jacobian nonzeros. | 
 |   int num_jacobian_nonzeros = 0; | 
 |   for (auto* residual_block : residual_blocks) { | 
 |     const int num_residuals = residual_block->NumResiduals(); | 
 |     const int num_parameter_blocks = residual_block->NumParameterBlocks(); | 
 |     for (int j = 0; j < num_parameter_blocks; ++j) { | 
 |       ParameterBlock* parameter_block = residual_block->parameter_blocks()[j]; | 
 |       if (!parameter_block->IsConstant()) { | 
 |         num_jacobian_nonzeros += num_residuals * parameter_block->TangentSize(); | 
 |       } | 
 |     } | 
 |   } | 
 |  | 
 |   // Allocate storage for the jacobian with some extra space at the end. | 
 |   // Allocate more space than needed to store the jacobian so that when the LM | 
 |   // algorithm adds the diagonal, no reallocation is necessary. This reduces | 
 |   // peak memory usage significantly. | 
 |   std::unique_ptr<CompressedRowSparseMatrix> jacobian = | 
 |       std::make_unique<CompressedRowSparseMatrix>( | 
 |           total_num_residuals, | 
 |           total_num_effective_parameters, | 
 |           num_jacobian_nonzeros + total_num_effective_parameters); | 
 |  | 
 |   // At this stage, the CompressedRowSparseMatrix is an invalid state. But this | 
 |   // seems to be the only way to construct it without doing a memory copy. | 
 |   int* rows = jacobian->mutable_rows(); | 
 |   int* cols = jacobian->mutable_cols(); | 
 |  | 
 |   int row_pos = 0; | 
 |   rows[0] = 0; | 
 |   for (auto* residual_block : residual_blocks) { | 
 |     const int num_parameter_blocks = residual_block->NumParameterBlocks(); | 
 |  | 
 |     // Count the number of derivatives for a row of this residual block and | 
 |     // build a list of active parameter block indices. | 
 |     int num_derivatives = 0; | 
 |     vector<int> parameter_indices; | 
 |     for (int j = 0; j < num_parameter_blocks; ++j) { | 
 |       ParameterBlock* parameter_block = residual_block->parameter_blocks()[j]; | 
 |       if (!parameter_block->IsConstant()) { | 
 |         parameter_indices.push_back(parameter_block->index()); | 
 |         num_derivatives += parameter_block->TangentSize(); | 
 |       } | 
 |     } | 
 |  | 
 |     // Sort the parameters by their position in the state vector. | 
 |     sort(parameter_indices.begin(), parameter_indices.end()); | 
 |     if (adjacent_find(parameter_indices.begin(), parameter_indices.end()) != | 
 |         parameter_indices.end()) { | 
 |       std::string parameter_block_description; | 
 |       for (int j = 0; j < num_parameter_blocks; ++j) { | 
 |         ParameterBlock* parameter_block = residual_block->parameter_blocks()[j]; | 
 |         parameter_block_description += parameter_block->ToString() + "\n"; | 
 |       } | 
 |       LOG(FATAL) << "Ceres internal error: " | 
 |                  << "Duplicate parameter blocks detected in a cost function. " | 
 |                  << "This should never happen. Please report this to " | 
 |                  << "the Ceres developers.\n" | 
 |                  << "Residual Block: " << residual_block->ToString() << "\n" | 
 |                  << "Parameter Blocks: " << parameter_block_description; | 
 |     } | 
 |  | 
 |     // Update the row indices. | 
 |     const int num_residuals = residual_block->NumResiduals(); | 
 |     for (int j = 0; j < num_residuals; ++j) { | 
 |       rows[row_pos + j + 1] = rows[row_pos + j] + num_derivatives; | 
 |     } | 
 |  | 
 |     // Iterate over parameter blocks in the order which they occur in the | 
 |     // parameter vector. This code mirrors that in Write(), where jacobian | 
 |     // values are updated. | 
 |     int col_pos = 0; | 
 |     for (int parameter_index : parameter_indices) { | 
 |       ParameterBlock* parameter_block = | 
 |           program_->parameter_blocks()[parameter_index]; | 
 |       const int parameter_block_size = parameter_block->TangentSize(); | 
 |  | 
 |       for (int r = 0; r < num_residuals; ++r) { | 
 |         // This is the position in the values array of the jacobian where this | 
 |         // row of the jacobian block should go. | 
 |         const int column_block_begin = rows[row_pos + r] + col_pos; | 
 |  | 
 |         for (int c = 0; c < parameter_block_size; ++c) { | 
 |           cols[column_block_begin + c] = parameter_block->delta_offset() + c; | 
 |         } | 
 |       } | 
 |       col_pos += parameter_block_size; | 
 |     } | 
 |     row_pos += num_residuals; | 
 |   } | 
 |   CHECK_EQ(num_jacobian_nonzeros, rows[total_num_residuals]); | 
 |  | 
 |   PopulateJacobianRowAndColumnBlockVectors(program_, jacobian.get()); | 
 |  | 
 |   return jacobian; | 
 | } | 
 |  | 
 | void CompressedRowJacobianWriter::Write(int residual_id, | 
 |                                         int residual_offset, | 
 |                                         double** jacobians, | 
 |                                         SparseMatrix* base_jacobian) { | 
 |   auto* jacobian = down_cast<CompressedRowSparseMatrix*>(base_jacobian); | 
 |  | 
 |   double* jacobian_values = jacobian->mutable_values(); | 
 |   const int* jacobian_rows = jacobian->rows(); | 
 |  | 
 |   const ResidualBlock* residual_block = | 
 |       program_->residual_blocks()[residual_id]; | 
 |   const int num_residuals = residual_block->NumResiduals(); | 
 |  | 
 |   vector<pair<int, int>> evaluated_jacobian_blocks; | 
 |   GetOrderedParameterBlocks(program_, residual_id, &evaluated_jacobian_blocks); | 
 |  | 
 |   // Where in the current row does the jacobian for a parameter block begin. | 
 |   int col_pos = 0; | 
 |  | 
 |   // Iterate over the jacobian blocks in increasing order of their | 
 |   // positions in the reduced parameter vector. | 
 |   for (auto& evaluated_jacobian_block : evaluated_jacobian_blocks) { | 
 |     const ParameterBlock* parameter_block = | 
 |         program_->parameter_blocks()[evaluated_jacobian_block.first]; | 
 |     const int argument = evaluated_jacobian_block.second; | 
 |     const int parameter_block_size = parameter_block->TangentSize(); | 
 |  | 
 |     // Copy one row of the jacobian block at a time. | 
 |     for (int r = 0; r < num_residuals; ++r) { | 
 |       // Position of the r^th row of the current jacobian block. | 
 |       const double* block_row_begin = | 
 |           jacobians[argument] + r * parameter_block_size; | 
 |  | 
 |       // Position in the values array of the jacobian where this | 
 |       // row of the jacobian block should go. | 
 |       double* column_block_begin = | 
 |           jacobian_values + jacobian_rows[residual_offset + r] + col_pos; | 
 |  | 
 |       std::copy(block_row_begin, | 
 |                 block_row_begin + parameter_block_size, | 
 |                 column_block_begin); | 
 |     } | 
 |     col_pos += parameter_block_size; | 
 |   } | 
 | } | 
 |  | 
 | }  // namespace ceres::internal |