| // 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: |
| // |
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| // 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) |
| |
| #ifndef CERES_INTERNAL_SPARSE_CHOLESKY_H_ |
| #define CERES_INTERNAL_SPARSE_CHOLESKY_H_ |
| |
| // This include must come before any #ifndef check on Ceres compile options. |
| #include "ceres/internal/port.h" |
| |
| #include "ceres/linear_solver.h" |
| #include "glog/logging.h" |
| |
| namespace ceres { |
| namespace internal { |
| |
| // An interface that abstracts away the internal details of various |
| // sparse linear algebra libraries and offers a simple API for solving |
| // symmetric positive definite linear systems using a sparse Cholesky |
| // factorization. |
| // |
| // Instances of SparseCholesky are expected to cache the symbolic |
| // factorization of the linear system. They do this on the first call |
| // to Factorize or FactorAndSolve. Subsequent calls to Factorize and |
| // FactorAndSolve are expected to have the same sparsity structure. |
| // |
| // Example usage: |
| // |
| // scoped_ptr<SparseCholesky> |
| // sparse_cholesky(SparseCholesky::Create(SUITE_SPARSE, AMD)); |
| // |
| // CompressedRowSparseMatrix lhs = ...; |
| // std::string message; |
| // CHECK_EQ(sparse_cholesky->Factorize(&lhs, &message), LINEAR_SOLVER_SUCCESS); |
| // Vector rhs = ...; |
| // Vector solution = ...; |
| // CHECK_EQ(sparse_cholesky->Solve(rhs.data(), solution.data(), &message), |
| // LINEAR_SOLVER_SUCCESS); |
| |
| class SparseCholesky { |
| public: |
| // Factory which returns an instance of SparseCholesky for the given |
| // sparse linear algebra library and fill reducing ordering |
| // strategy. |
| // |
| // Caller owns the result. |
| static SparseCholesky* Create( |
| SparseLinearAlgebraLibraryType sparse_linear_algebra_library_type, |
| OrderingType ordering_type); |
| |
| virtual ~SparseCholesky(); |
| |
| // Due to the symmetry of the linear system, sparse linear algebra |
| // libraries only use one half of the input matrix. Whether it is |
| // the upper or the lower triangular part of the matrix depends on |
| // the library and the re-ordering strategy being used. This |
| // function tells the user the storage type expected of the input |
| // matrix for the sparse linear algebra library and reordering |
| // strategy used. |
| virtual CompressedRowSparseMatrix::StorageType StorageType() const = 0; |
| |
| // Computes the numeric factorization of the given matrix. If this |
| // is the first call to Factorize, first the symbolic factorization |
| // will be computed and cached and the numeric factorization will be |
| // computed based on that. |
| // |
| // Subsequent calls to Factorize will use that symbolic |
| // factorization assuming that the sparsity of the matrix has |
| // remained constant. |
| virtual LinearSolverTerminationType Factorize( |
| CompressedRowSparseMatrix* lhs, std::string* message) = 0; |
| |
| // Computes the solution to the equation |
| // |
| // lhs * solution = rhs |
| // |
| // rhs and solution can point to the same memory location. |
| virtual LinearSolverTerminationType Solve(const double* rhs, |
| double* solution, |
| std::string* message) = 0; |
| |
| // Convenience method which combines a call to Factorize and |
| // Solve. Solve is only called if Factorize returns |
| // LINEAR_SOLVER_SUCCESS. |
| virtual LinearSolverTerminationType FactorAndSolve( |
| CompressedRowSparseMatrix* lhs, |
| const double* rhs, |
| double* solution, |
| std::string* message); |
| |
| }; |
| |
| } // namespace internal |
| } // namespace ceres |
| |
| #endif // CERES_INTERNAL_SPARSE_CHOLESKY_H_ |