|  | // Ceres Solver - A fast non-linear least squares minimizer | 
|  | // Copyright 2017 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" | 
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|  | // | 
|  | // Author: sameeragarwal@google.com (Sameer Agarwal) | 
|  |  | 
|  | #include "ceres/subset_preconditioner.h" | 
|  |  | 
|  | #include <memory> | 
|  |  | 
|  | #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/eigen.h" | 
|  | #include "glog/logging.h" | 
|  | #include "gtest/gtest.h" | 
|  |  | 
|  | namespace ceres { | 
|  | namespace 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::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); | 
|  | 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); | 
|  | 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::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_; | 
|  | }; | 
|  |  | 
|  | 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_->RightMultiply(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_CXSPARSE | 
|  | INSTANTIATE_TEST_SUITE_P(SubsetPreconditionerWithCXSparse, | 
|  | SubsetPreconditionerTest, | 
|  | ::testing::Combine(::testing::Values(CX_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 internal | 
|  | }  // namespace ceres |