cart-elc

Source code for CART-ELC
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SolveWithGuess.h (4212B)

      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 EIGEN_CONSTEXPR
     54   Index rows() const EIGEN_NOEXCEPT { return m_dec.cols(); }
     55   EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR
     56   Index cols() const EIGEN_NOEXCEPT { return m_rhs.cols(); }
     57 
     58   EIGEN_DEVICE_FUNC const Decomposition& dec()   const { return m_dec; }
     59   EIGEN_DEVICE_FUNC const RhsType&       rhs()   const { return m_rhs; }
     60   EIGEN_DEVICE_FUNC const GuessType&     guess() const { return m_guess; }
     61 
     62 protected:
     63   const Decomposition &m_dec;
     64   const RhsType       &m_rhs;
     65   const GuessType     &m_guess;
     66 
     67 private:
     68   Scalar coeff(Index row, Index col) const;
     69   Scalar coeff(Index i) const;
     70 };
     71 
     72 namespace internal {
     73 
     74 // Evaluator of SolveWithGuess -> eval into a temporary
     75 template<typename Decomposition, typename RhsType, typename GuessType>
     76 struct evaluator<SolveWithGuess<Decomposition,RhsType, GuessType> >
     77   : public evaluator<typename SolveWithGuess<Decomposition,RhsType,GuessType>::PlainObject>
     78 {
     79   typedef SolveWithGuess<Decomposition,RhsType,GuessType> SolveType;
     80   typedef typename SolveType::PlainObject PlainObject;
     81   typedef evaluator<PlainObject> Base;
     82 
     83   evaluator(const SolveType& solve)
     84     : m_result(solve.rows(), solve.cols())
     85   {
     86     ::new (static_cast<Base*>(this)) Base(m_result);
     87     m_result = solve.guess();
     88     solve.dec()._solve_with_guess_impl(solve.rhs(), m_result);
     89   }
     90 
     91 protected:
     92   PlainObject m_result;
     93 };
     94 
     95 // Specialization for "dst = dec.solveWithGuess(rhs)"
     96 // NOTE we need to specialize it for Dense2Dense to avoid ambiguous specialization error and a Sparse2Sparse specialization must exist somewhere
     97 template<typename DstXprType, typename DecType, typename RhsType, typename GuessType, typename Scalar>
     98 struct Assignment<DstXprType, SolveWithGuess<DecType,RhsType,GuessType>, internal::assign_op<Scalar,Scalar>, Dense2Dense>
     99 {
    100   typedef SolveWithGuess<DecType,RhsType,GuessType> SrcXprType;
    101   static void run(DstXprType &dst, const SrcXprType &src, const internal::assign_op<Scalar,Scalar> &)
    102   {
    103     Index dstRows = src.rows();
    104     Index dstCols = src.cols();
    105     if((dst.rows()!=dstRows) || (dst.cols()!=dstCols))
    106       dst.resize(dstRows, dstCols);
    107 
    108     dst = src.guess();
    109     src.dec()._solve_with_guess_impl(src.rhs(), dst/*, src.guess()*/);
    110   }
    111 };
    112 
    113 } // end namespace internal
    114 
    115 } // end namespace Eigen
    116 
    117 #endif // EIGEN_SOLVEWITHGUESS_H