| // Ceres Solver - A fast non-linear least squares minimizer |
| // Copyright 2023 Google Inc. All rights reserved. |
| // http://ceres-solver.org/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // |
| // * Redistributions of source code must retain the above copyright notice, |
| // this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above copyright notice, |
| // this list of conditions and the following disclaimer in the documentation |
| // and/or other materials provided with the distribution. |
| // * Neither the name of Google Inc. nor the names of its contributors may be |
| // used to endorse or promote products derived from this software without |
| // specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| // POSSIBILITY OF SUCH DAMAGE. |
| // |
| // Author: sameeragarwal@google.com (Sameer Agarwal) |
| |
| #include "ceres/parameter_block_ordering.h" |
| |
| #include <map> |
| #include <memory> |
| #include <set> |
| #include <vector> |
| |
| #include "absl/log/check.h" |
| #include "ceres/event_logger.h" |
| #include "ceres/graph.h" |
| #include "ceres/graph_algorithms.h" |
| #include "ceres/map_util.h" |
| #include "ceres/parameter_block.h" |
| #include "ceres/program.h" |
| #include "ceres/residual_block.h" |
| |
| namespace ceres::internal { |
| |
| int ComputeStableSchurOrdering(const Program& program, |
| std::vector<ParameterBlock*>* ordering) { |
| CHECK(ordering != nullptr); |
| ordering->clear(); |
| EventLogger event_logger("ComputeStableSchurOrdering"); |
| auto graph = CreateHessianGraph(program); |
| event_logger.AddEvent("CreateHessianGraph"); |
| |
| const std::vector<ParameterBlock*>& parameter_blocks = |
| program.parameter_blocks(); |
| const auto& vertices = graph->vertices(); |
| for (auto* parameter_block : parameter_blocks) { |
| if (vertices.count(parameter_block) > 0) { |
| ordering->push_back(parameter_block); |
| } |
| } |
| event_logger.AddEvent("Preordering"); |
| |
| int independent_set_size = StableIndependentSetOrdering(*graph, ordering); |
| event_logger.AddEvent("StableIndependentSet"); |
| |
| // Add the excluded blocks to back of the ordering vector. |
| for (auto* parameter_block : parameter_blocks) { |
| if (parameter_block->IsConstant()) { |
| ordering->push_back(parameter_block); |
| } |
| } |
| event_logger.AddEvent("ConstantParameterBlocks"); |
| |
| return independent_set_size; |
| } |
| |
| int ComputeSchurOrdering(const Program& program, |
| std::vector<ParameterBlock*>* ordering) { |
| CHECK(ordering != nullptr); |
| ordering->clear(); |
| |
| auto graph = CreateHessianGraph(program); |
| int independent_set_size = IndependentSetOrdering(*graph, ordering); |
| const std::vector<ParameterBlock*>& parameter_blocks = |
| program.parameter_blocks(); |
| |
| // Add the excluded blocks to back of the ordering vector. |
| for (auto* parameter_block : parameter_blocks) { |
| if (parameter_block->IsConstant()) { |
| ordering->push_back(parameter_block); |
| } |
| } |
| |
| return independent_set_size; |
| } |
| |
| void ComputeRecursiveIndependentSetOrdering(const Program& program, |
| ParameterBlockOrdering* ordering) { |
| CHECK(ordering != nullptr); |
| ordering->Clear(); |
| const std::vector<ParameterBlock*> parameter_blocks = |
| program.parameter_blocks(); |
| auto graph = CreateHessianGraph(program); |
| |
| int num_covered = 0; |
| int round = 0; |
| while (num_covered < parameter_blocks.size()) { |
| std::vector<ParameterBlock*> independent_set_ordering; |
| const int independent_set_size = |
| IndependentSetOrdering(*graph, &independent_set_ordering); |
| for (int i = 0; i < independent_set_size; ++i) { |
| ParameterBlock* parameter_block = independent_set_ordering[i]; |
| ordering->AddElementToGroup(parameter_block->mutable_user_state(), round); |
| graph->RemoveVertex(parameter_block); |
| } |
| num_covered += independent_set_size; |
| ++round; |
| } |
| } |
| |
| std::unique_ptr<Graph<ParameterBlock*>> CreateHessianGraph( |
| const Program& program) { |
| auto graph = std::make_unique<Graph<ParameterBlock*>>(); |
| CHECK(graph != nullptr); |
| const std::vector<ParameterBlock*>& parameter_blocks = |
| program.parameter_blocks(); |
| for (auto* parameter_block : parameter_blocks) { |
| if (!parameter_block->IsConstant()) { |
| graph->AddVertex(parameter_block); |
| } |
| } |
| |
| const std::vector<ResidualBlock*>& residual_blocks = |
| program.residual_blocks(); |
| for (auto* residual_block : residual_blocks) { |
| const int num_parameter_blocks = residual_block->NumParameterBlocks(); |
| ParameterBlock* const* parameter_blocks = |
| residual_block->parameter_blocks(); |
| for (int j = 0; j < num_parameter_blocks; ++j) { |
| if (parameter_blocks[j]->IsConstant()) { |
| continue; |
| } |
| |
| for (int k = j + 1; k < num_parameter_blocks; ++k) { |
| if (parameter_blocks[k]->IsConstant()) { |
| continue; |
| } |
| |
| graph->AddEdge(parameter_blocks[j], parameter_blocks[k]); |
| } |
| } |
| } |
| |
| return graph; |
| } |
| |
| void OrderingToGroupSizes(const ParameterBlockOrdering* ordering, |
| std::vector<int>* group_sizes) { |
| CHECK(group_sizes != nullptr); |
| group_sizes->clear(); |
| if (ordering == nullptr) { |
| return; |
| } |
| |
| // TODO(sameeragarwal): Investigate if this should be a set or an |
| // unordered_set. |
| const std::map<int, std::set<double*>>& group_to_elements = |
| ordering->group_to_elements(); |
| for (const auto& g_t_e : group_to_elements) { |
| group_sizes->push_back(g_t_e.second.size()); |
| } |
| } |
| |
| } // namespace ceres::internal |