1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2014 Gael Guennebaud <gael.guennebaud@inria.fr> 5 // 6 // This Source Code Form is subject to the terms of the Mozilla 7 // Public License v. 2.0. If a copy of the MPL was not distributed 8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. 9 10 #ifndef EIGEN_SOLVEWITHGUESS_H 11 #define EIGEN_SOLVEWITHGUESS_H 12 13 namespace Eigen { 14 15 template<typename Decomposition, typename RhsType, typename GuessType> class SolveWithGuess; 16 17 /** \class SolveWithGuess 18 * \ingroup IterativeLinearSolvers_Module 19 * 20 * \brief Pseudo expression representing a solving operation 21 * 22 * \tparam Decomposition the type of the matrix or decomposion object 23 * \tparam Rhstype the type of the right-hand side 24 * 25 * This class represents an expression of A.solve(B) 26 * and most of the time this is the only way it is used. 27 * 28 */ 29 namespace internal { 30 31 32 template<typename Decomposition, typename RhsType, typename GuessType> 33 struct traits<SolveWithGuess<Decomposition, RhsType, GuessType> > 34 : traits<Solve<Decomposition,RhsType> > 35 {}; 36 37 } 38 39 40 template<typename Decomposition, typename RhsType, typename GuessType> 41 class SolveWithGuess : public internal::generic_xpr_base<SolveWithGuess<Decomposition,RhsType,GuessType>, MatrixXpr, typename internal::traits<RhsType>::StorageKind>::type 42 { 43 public: 44 typedef typename internal::traits<SolveWithGuess>::Scalar Scalar; 45 typedef typename internal::traits<SolveWithGuess>::PlainObject PlainObject; 46 typedef typename internal::generic_xpr_base<SolveWithGuess<Decomposition,RhsType,GuessType>, MatrixXpr, typename internal::traits<RhsType>::StorageKind>::type Base; 47 typedef typename internal::ref_selector<SolveWithGuess>::type Nested; 48 49 SolveWithGuess(const Decomposition &dec, const RhsType &rhs, const GuessType &guess) 50 : m_dec(dec), m_rhs(rhs), m_guess(guess) 51 {} 52 53 EIGEN_DEVICE_FUNC Index rows() const { return m_dec.cols(); } 54 EIGEN_DEVICE_FUNC Index cols() const { return m_rhs.cols(); } 55 56 EIGEN_DEVICE_FUNC const Decomposition& dec() const { return m_dec; } 57 EIGEN_DEVICE_FUNC const RhsType& rhs() const { return m_rhs; } 58 EIGEN_DEVICE_FUNC const GuessType& guess() const { return m_guess; } 59 60 protected: 61 const Decomposition &m_dec; 62 const RhsType &m_rhs; 63 const GuessType &m_guess; 64 65 private: 66 Scalar coeff(Index row, Index col) const; 67 Scalar coeff(Index i) const; 68 }; 69 70 namespace internal { 71 72 // Evaluator of SolveWithGuess -> eval into a temporary 73 template<typename Decomposition, typename RhsType, typename GuessType> 74 struct evaluator<SolveWithGuess<Decomposition,RhsType, GuessType> > 75 : public evaluator<typename SolveWithGuess<Decomposition,RhsType,GuessType>::PlainObject> 76 { 77 typedef SolveWithGuess<Decomposition,RhsType,GuessType> SolveType; 78 typedef typename SolveType::PlainObject PlainObject; 79 typedef evaluator<PlainObject> Base; 80 81 evaluator(const SolveType& solve) 82 : m_result(solve.rows(), solve.cols()) 83 { 84 ::new (static_cast<Base*>(this)) Base(m_result); 85 m_result = solve.guess(); 86 solve.dec()._solve_with_guess_impl(solve.rhs(), m_result); 87 } 88 89 protected: 90 PlainObject m_result; 91 }; 92 93 // Specialization for "dst = dec.solveWithGuess(rhs)" 94 // NOTE we need to specialize it for Dense2Dense to avoid ambiguous specialization error and a Sparse2Sparse specialization must exist somewhere 95 template<typename DstXprType, typename DecType, typename RhsType, typename GuessType, typename Scalar> 96 struct Assignment<DstXprType, SolveWithGuess<DecType,RhsType,GuessType>, internal::assign_op<Scalar,Scalar>, Dense2Dense> 97 { 98 typedef SolveWithGuess<DecType,RhsType,GuessType> SrcXprType; 99 static void run(DstXprType &dst, const SrcXprType &src, const internal::assign_op<Scalar,Scalar> &) 100 { 101 Index dstRows = src.rows(); 102 Index dstCols = src.cols(); 103 if((dst.rows()!=dstRows) || (dst.cols()!=dstCols)) 104 dst.resize(dstRows, dstCols); 105 106 dst = src.guess(); 107 src.dec()._solve_with_guess_impl(src.rhs(), dst/*, src.guess()*/); 108 } 109 }; 110 111 } // end namepsace internal 112 113 } // end namespace Eigen 114 115 #endif // EIGEN_SOLVEWITHGUESS_H 116