| // Ceres Solver - A fast non-linear least squares minimizer | 
 | // Copyright 2022 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/subset_preconditioner.h" | 
 |  | 
 | #include <memory> | 
 | #include <random> | 
 |  | 
 | #include "Eigen/Dense" | 
 | #include "Eigen/SparseCore" | 
 | #include "ceres/block_sparse_matrix.h" | 
 | #include "ceres/compressed_row_sparse_matrix.h" | 
 | #include "ceres/inner_product_computer.h" | 
 | #include "ceres/internal/config.h" | 
 | #include "ceres/internal/eigen.h" | 
 | #include "glog/logging.h" | 
 | #include "gtest/gtest.h" | 
 |  | 
 | namespace ceres::internal { | 
 |  | 
 | namespace { | 
 |  | 
 | // TODO(sameeragarwal): Refactor the following two functions out of | 
 | // here and sparse_cholesky_test.cc into a more suitable place. | 
 | template <int UpLoType> | 
 | bool SolveLinearSystemUsingEigen(const Matrix& lhs, | 
 |                                  const Vector rhs, | 
 |                                  Vector* solution) { | 
 |   Eigen::LLT<Matrix, UpLoType> llt = lhs.selfadjointView<UpLoType>().llt(); | 
 |   if (llt.info() != Eigen::Success) { | 
 |     return false; | 
 |   } | 
 |   *solution = llt.solve(rhs); | 
 |   return (llt.info() == Eigen::Success); | 
 | } | 
 |  | 
 | // Use Eigen's Dense Cholesky solver to compute the solution to a | 
 | // sparse linear system. | 
 | bool ComputeExpectedSolution(const CompressedRowSparseMatrix& lhs, | 
 |                              const Vector& rhs, | 
 |                              Vector* solution) { | 
 |   Matrix dense_triangular_lhs; | 
 |   lhs.ToDenseMatrix(&dense_triangular_lhs); | 
 |   if (lhs.storage_type() == | 
 |       CompressedRowSparseMatrix::StorageType::UPPER_TRIANGULAR) { | 
 |     Matrix full_lhs = dense_triangular_lhs.selfadjointView<Eigen::Upper>(); | 
 |     return SolveLinearSystemUsingEigen<Eigen::Upper>(full_lhs, rhs, solution); | 
 |   } | 
 |   return SolveLinearSystemUsingEigen<Eigen::Lower>( | 
 |       dense_triangular_lhs, rhs, solution); | 
 | } | 
 |  | 
 | using Param = ::testing::tuple<SparseLinearAlgebraLibraryType, bool>; | 
 |  | 
 | std::string ParamInfoToString(testing::TestParamInfo<Param> info) { | 
 |   Param param = info.param; | 
 |   std::stringstream ss; | 
 |   ss << SparseLinearAlgebraLibraryTypeToString(::testing::get<0>(param)) << "_" | 
 |      << (::testing::get<1>(param) ? "Diagonal" : "NoDiagonal"); | 
 |   return ss.str(); | 
 | } | 
 |  | 
 | }  // namespace | 
 |  | 
 | class SubsetPreconditionerTest : public ::testing::TestWithParam<Param> { | 
 |  protected: | 
 |   void SetUp() final { | 
 |     BlockSparseMatrix::RandomMatrixOptions options; | 
 |     options.num_col_blocks = 4; | 
 |     options.min_col_block_size = 1; | 
 |     options.max_col_block_size = 4; | 
 |     options.num_row_blocks = 8; | 
 |     options.min_row_block_size = 1; | 
 |     options.max_row_block_size = 4; | 
 |     options.block_density = 0.9; | 
 |  | 
 |     m_ = BlockSparseMatrix::CreateRandomMatrix(options, prng); | 
 |     start_row_block_ = m_->block_structure()->rows.size(); | 
 |  | 
 |     // Ensure that the bottom part of the matrix has the same column | 
 |     // block structure. | 
 |     options.col_blocks = m_->block_structure()->cols; | 
 |     b_ = BlockSparseMatrix::CreateRandomMatrix(options, prng); | 
 |     m_->AppendRows(*b_); | 
 |  | 
 |     // Create a Identity block diagonal matrix with the same column | 
 |     // block structure. | 
 |     diagonal_ = Vector::Ones(m_->num_cols()); | 
 |     block_diagonal_ = BlockSparseMatrix::CreateDiagonalMatrix( | 
 |         diagonal_.data(), b_->block_structure()->cols); | 
 |  | 
 |     // Unconditionally add the block diagonal to the matrix b_, | 
 |     // because either it is either part of b_ to make it full rank, or | 
 |     // we pass the same diagonal matrix later as the parameter D. In | 
 |     // either case the preconditioner matrix is b_' b + D'D. | 
 |     b_->AppendRows(*block_diagonal_); | 
 |     inner_product_computer_ = InnerProductComputer::Create( | 
 |         *b_, CompressedRowSparseMatrix::StorageType::UPPER_TRIANGULAR); | 
 |     inner_product_computer_->Compute(); | 
 |   } | 
 |  | 
 |   std::unique_ptr<BlockSparseMatrix> m_; | 
 |   std::unique_ptr<BlockSparseMatrix> b_; | 
 |   std::unique_ptr<BlockSparseMatrix> block_diagonal_; | 
 |   std::unique_ptr<InnerProductComputer> inner_product_computer_; | 
 |   std::unique_ptr<Preconditioner> preconditioner_; | 
 |   Vector diagonal_; | 
 |   int start_row_block_; | 
 |   std::mt19937 prng; | 
 | }; | 
 |  | 
 | TEST_P(SubsetPreconditionerTest, foo) { | 
 |   Param param = GetParam(); | 
 |   Preconditioner::Options options; | 
 |   options.subset_preconditioner_start_row_block = start_row_block_; | 
 |   options.sparse_linear_algebra_library_type = ::testing::get<0>(param); | 
 |   preconditioner_ = std::make_unique<SubsetPreconditioner>(options, *m_); | 
 |  | 
 |   const bool with_diagonal = ::testing::get<1>(param); | 
 |   if (!with_diagonal) { | 
 |     m_->AppendRows(*block_diagonal_); | 
 |   } | 
 |  | 
 |   EXPECT_TRUE( | 
 |       preconditioner_->Update(*m_, with_diagonal ? diagonal_.data() : nullptr)); | 
 |  | 
 |   // Repeatedly apply the preconditioner to random vectors and check | 
 |   // that the preconditioned value is the same as one obtained by | 
 |   // solving the linear system directly. | 
 |   for (int i = 0; i < 5; ++i) { | 
 |     CompressedRowSparseMatrix* lhs = inner_product_computer_->mutable_result(); | 
 |     Vector rhs = Vector::Random(lhs->num_rows()); | 
 |     Vector expected(lhs->num_rows()); | 
 |     EXPECT_TRUE(ComputeExpectedSolution(*lhs, rhs, &expected)); | 
 |  | 
 |     Vector actual(lhs->num_rows()); | 
 |     preconditioner_->RightMultiplyAndAccumulate(rhs.data(), actual.data()); | 
 |  | 
 |     Matrix eigen_lhs; | 
 |     lhs->ToDenseMatrix(&eigen_lhs); | 
 |     EXPECT_NEAR((actual - expected).norm() / actual.norm(), | 
 |                 0.0, | 
 |                 std::numeric_limits<double>::epsilon() * 10) | 
 |         << "\n" | 
 |         << eigen_lhs << "\n" | 
 |         << expected.transpose() << "\n" | 
 |         << actual.transpose(); | 
 |   } | 
 | } | 
 |  | 
 | #ifndef CERES_NO_SUITESPARSE | 
 | INSTANTIATE_TEST_SUITE_P(SubsetPreconditionerWithSuiteSparse, | 
 |                          SubsetPreconditionerTest, | 
 |                          ::testing::Combine(::testing::Values(SUITE_SPARSE), | 
 |                                             ::testing::Values(true, false)), | 
 |                          ParamInfoToString); | 
 | #endif | 
 |  | 
 | #ifndef CERES_NO_ACCELERATE_SPARSE | 
 | INSTANTIATE_TEST_SUITE_P( | 
 |     SubsetPreconditionerWithAccelerateSparse, | 
 |     SubsetPreconditionerTest, | 
 |     ::testing::Combine(::testing::Values(ACCELERATE_SPARSE), | 
 |                        ::testing::Values(true, false)), | 
 |     ParamInfoToString); | 
 | #endif | 
 |  | 
 | #ifdef CERES_USE_EIGEN_SPARSE | 
 | INSTANTIATE_TEST_SUITE_P(SubsetPreconditionerWithEigenSparse, | 
 |                          SubsetPreconditionerTest, | 
 |                          ::testing::Combine(::testing::Values(EIGEN_SPARSE), | 
 |                                             ::testing::Values(true, false)), | 
 |                          ParamInfoToString); | 
 | #endif | 
 |  | 
 | }  // namespace ceres::internal |