|  | // Ceres Solver - A fast non-linear least squares minimizer | 
|  | // Copyright 2018 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/iterative_refiner.h" | 
|  |  | 
|  | #include <utility> | 
|  |  | 
|  | #include "Eigen/Dense" | 
|  | #include "ceres/dense_cholesky.h" | 
|  | #include "ceres/internal/eigen.h" | 
|  | #include "ceres/sparse_cholesky.h" | 
|  | #include "ceres/sparse_matrix.h" | 
|  | #include "glog/logging.h" | 
|  | #include "gtest/gtest.h" | 
|  |  | 
|  | namespace ceres::internal { | 
|  |  | 
|  | // Macros to help us define virtual methods which we do not expect to | 
|  | // use/call in this test. | 
|  | #define DO_NOT_CALL \ | 
|  | { LOG(FATAL) << "DO NOT CALL"; } | 
|  | #define DO_NOT_CALL_WITH_RETURN(x) \ | 
|  | {                                \ | 
|  | LOG(FATAL) << "DO NOT CALL";   \ | 
|  | return x;                      \ | 
|  | } | 
|  |  | 
|  | // A fake SparseMatrix, which uses an Eigen matrix to do the real work. | 
|  | class FakeSparseMatrix : public SparseMatrix { | 
|  | public: | 
|  | explicit FakeSparseMatrix(Matrix m) : m_(std::move(m)) {} | 
|  |  | 
|  | // y += Ax | 
|  | void RightMultiplyAndAccumulate(const double* x, double* y) const final { | 
|  | VectorRef(y, m_.cols()) += m_ * ConstVectorRef(x, m_.cols()); | 
|  | } | 
|  | // y += A'x | 
|  | void LeftMultiplyAndAccumulate(const double* x, double* y) const final { | 
|  | // We will assume that this is a symmetric matrix. | 
|  | RightMultiplyAndAccumulate(x, y); | 
|  | } | 
|  |  | 
|  | double* mutable_values() final { return m_.data(); } | 
|  | const double* values() const final { return m_.data(); } | 
|  | int num_rows() const final { return m_.cols(); } | 
|  | int num_cols() const final { return m_.cols(); } | 
|  | int num_nonzeros() const final { return m_.cols() * m_.cols(); } | 
|  |  | 
|  | // The following methods are not needed for tests in this file. | 
|  | void SquaredColumnNorm(double* x) const final DO_NOT_CALL; | 
|  | void ScaleColumns(const double* scale) final DO_NOT_CALL; | 
|  | void SetZero() final DO_NOT_CALL; | 
|  | void ToDenseMatrix(Matrix* dense_matrix) const final DO_NOT_CALL; | 
|  | void ToTextFile(FILE* file) const final DO_NOT_CALL; | 
|  |  | 
|  | private: | 
|  | Matrix m_; | 
|  | }; | 
|  |  | 
|  | // A fake SparseCholesky which uses Eigen's Cholesky factorization to | 
|  | // do the real work. The template parameter allows us to work in | 
|  | // doubles or floats, even though the source matrix is double. | 
|  | template <typename Scalar> | 
|  | class FakeSparseCholesky : public SparseCholesky { | 
|  | public: | 
|  | explicit FakeSparseCholesky(const Matrix& lhs) { lhs_ = lhs.cast<Scalar>(); } | 
|  |  | 
|  | LinearSolverTerminationType Solve(const double* rhs_ptr, | 
|  | double* solution_ptr, | 
|  | std::string* message) final { | 
|  | const int num_cols = lhs_.cols(); | 
|  | VectorRef solution(solution_ptr, num_cols); | 
|  | ConstVectorRef rhs(rhs_ptr, num_cols); | 
|  | auto llt = lhs_.llt(); | 
|  | CHECK_EQ(llt.info(), Eigen::Success); | 
|  | solution = llt.solve(rhs.cast<Scalar>()).template cast<double>(); | 
|  | return LinearSolverTerminationType::SUCCESS; | 
|  | } | 
|  |  | 
|  | // The following methods are not needed for tests in this file. | 
|  | CompressedRowSparseMatrix::StorageType StorageType() const final | 
|  | DO_NOT_CALL_WITH_RETURN( | 
|  | CompressedRowSparseMatrix::StorageType::UPPER_TRIANGULAR); | 
|  | LinearSolverTerminationType Factorize(CompressedRowSparseMatrix* lhs, | 
|  | std::string* message) final | 
|  | DO_NOT_CALL_WITH_RETURN(LinearSolverTerminationType::FAILURE); | 
|  |  | 
|  | private: | 
|  | Eigen::Matrix<Scalar, Eigen::Dynamic, Eigen::Dynamic> lhs_; | 
|  | }; | 
|  |  | 
|  | // A fake DenseCholesky which uses Eigen's Cholesky factorization to | 
|  | // do the real work. The template parameter allows us to work in | 
|  | // doubles or floats, even though the source matrix is double. | 
|  | template <typename Scalar> | 
|  | class FakeDenseCholesky : public DenseCholesky { | 
|  | public: | 
|  | explicit FakeDenseCholesky(const Matrix& lhs) { lhs_ = lhs.cast<Scalar>(); } | 
|  |  | 
|  | LinearSolverTerminationType Solve(const double* rhs_ptr, | 
|  | double* solution_ptr, | 
|  | std::string* message) final { | 
|  | const int num_cols = lhs_.cols(); | 
|  | VectorRef solution(solution_ptr, num_cols); | 
|  | ConstVectorRef rhs(rhs_ptr, num_cols); | 
|  | solution = lhs_.llt().solve(rhs.cast<Scalar>()).template cast<double>(); | 
|  | return LinearSolverTerminationType::SUCCESS; | 
|  | } | 
|  |  | 
|  | LinearSolverTerminationType Factorize(int num_cols, | 
|  | double* lhs, | 
|  | std::string* message) final | 
|  | DO_NOT_CALL_WITH_RETURN(LinearSolverTerminationType::FAILURE); | 
|  |  | 
|  | private: | 
|  | Eigen::Matrix<Scalar, Eigen::Dynamic, Eigen::Dynamic> lhs_; | 
|  | }; | 
|  |  | 
|  | #undef DO_NOT_CALL | 
|  | #undef DO_NOT_CALL_WITH_RETURN | 
|  |  | 
|  | class SparseIterativeRefinerTest : public ::testing::Test { | 
|  | public: | 
|  | void SetUp() override { | 
|  | num_cols_ = 5; | 
|  | max_num_iterations_ = 30; | 
|  | Matrix m(num_cols_, num_cols_); | 
|  | m.setRandom(); | 
|  | lhs_ = m * m.transpose(); | 
|  | solution_.resize(num_cols_); | 
|  | solution_.setRandom(); | 
|  | rhs_ = lhs_ * solution_; | 
|  | }; | 
|  |  | 
|  | protected: | 
|  | int num_cols_; | 
|  | int max_num_iterations_; | 
|  | Matrix lhs_; | 
|  | Vector rhs_, solution_; | 
|  | }; | 
|  |  | 
|  | TEST_F(SparseIterativeRefinerTest, | 
|  | RandomSolutionWithExactFactorizationConverges) { | 
|  | FakeSparseMatrix lhs(lhs_); | 
|  | FakeSparseCholesky<double> sparse_cholesky(lhs_); | 
|  | SparseIterativeRefiner refiner(max_num_iterations_); | 
|  | Vector refined_solution(num_cols_); | 
|  | refined_solution.setRandom(); | 
|  | refiner.Refine(lhs, rhs_.data(), &sparse_cholesky, refined_solution.data()); | 
|  | EXPECT_NEAR((lhs_ * refined_solution - rhs_).norm(), | 
|  | 0.0, | 
|  | std::numeric_limits<double>::epsilon() * 10); | 
|  | } | 
|  |  | 
|  | TEST_F(SparseIterativeRefinerTest, | 
|  | RandomSolutionWithApproximationFactorizationConverges) { | 
|  | FakeSparseMatrix lhs(lhs_); | 
|  | // Use a single precision Cholesky factorization of the double | 
|  | // precision matrix. This will give us an approximate factorization. | 
|  | FakeSparseCholesky<float> sparse_cholesky(lhs_); | 
|  | SparseIterativeRefiner refiner(max_num_iterations_); | 
|  | Vector refined_solution(num_cols_); | 
|  | refined_solution.setRandom(); | 
|  | refiner.Refine(lhs, rhs_.data(), &sparse_cholesky, refined_solution.data()); | 
|  | EXPECT_NEAR((lhs_ * refined_solution - rhs_).norm(), | 
|  | 0.0, | 
|  | std::numeric_limits<double>::epsilon() * 10); | 
|  | } | 
|  |  | 
|  | class DenseIterativeRefinerTest : public ::testing::Test { | 
|  | public: | 
|  | void SetUp() override { | 
|  | num_cols_ = 5; | 
|  | max_num_iterations_ = 30; | 
|  | Matrix m(num_cols_, num_cols_); | 
|  | m.setRandom(); | 
|  | lhs_ = m * m.transpose(); | 
|  | solution_.resize(num_cols_); | 
|  | solution_.setRandom(); | 
|  | rhs_ = lhs_ * solution_; | 
|  | }; | 
|  |  | 
|  | protected: | 
|  | int num_cols_; | 
|  | int max_num_iterations_; | 
|  | Matrix lhs_; | 
|  | Vector rhs_, solution_; | 
|  | }; | 
|  |  | 
|  | TEST_F(DenseIterativeRefinerTest, | 
|  | RandomSolutionWithExactFactorizationConverges) { | 
|  | Matrix lhs = lhs_; | 
|  | FakeDenseCholesky<double> dense_cholesky(lhs); | 
|  | DenseIterativeRefiner refiner(max_num_iterations_); | 
|  | Vector refined_solution(num_cols_); | 
|  | refined_solution.setRandom(); | 
|  | refiner.Refine(lhs.cols(), | 
|  | lhs.data(), | 
|  | rhs_.data(), | 
|  | &dense_cholesky, | 
|  | refined_solution.data()); | 
|  | EXPECT_NEAR((lhs_ * refined_solution - rhs_).norm(), | 
|  | 0.0, | 
|  | std::numeric_limits<double>::epsilon() * 10); | 
|  | } | 
|  |  | 
|  | TEST_F(DenseIterativeRefinerTest, | 
|  | RandomSolutionWithApproximationFactorizationConverges) { | 
|  | Matrix lhs = lhs_; | 
|  | // Use a single precision Cholesky factorization of the double | 
|  | // precision matrix. This will give us an approximate factorization. | 
|  | FakeDenseCholesky<float> dense_cholesky(lhs_); | 
|  | DenseIterativeRefiner refiner(max_num_iterations_); | 
|  | Vector refined_solution(num_cols_); | 
|  | refined_solution.setRandom(); | 
|  | refiner.Refine(lhs.cols(), | 
|  | lhs.data(), | 
|  | rhs_.data(), | 
|  | &dense_cholesky, | 
|  | refined_solution.data()); | 
|  | EXPECT_NEAR((lhs_ * refined_solution - rhs_).norm(), | 
|  | 0.0, | 
|  | std::numeric_limits<double>::epsilon() * 10); | 
|  | } | 
|  |  | 
|  | }  // namespace ceres::internal |