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      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2015 Gael Guennebaud <gael.guennebaud (at) 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_SOLVERBASE_H
     11 #define EIGEN_SOLVERBASE_H
     12 
     13 namespace Eigen {
     14 
     15 namespace internal {
     16 
     17 
     18 
     19 } // end namespace internal
     20 
     21 /** \class SolverBase
     22   * \brief A base class for matrix decomposition and solvers
     23   *
     24   * \tparam Derived the actual type of the decomposition/solver.
     25   *
     26   * Any matrix decomposition inheriting this base class provide the following API:
     27   *
     28   * \code
     29   * MatrixType A, b, x;
     30   * DecompositionType dec(A);
     31   * x = dec.solve(b);             // solve A   * x = b
     32   * x = dec.transpose().solve(b); // solve A^T * x = b
     33   * x = dec.adjoint().solve(b);   // solve A'  * x = b
     34   * \endcode
     35   *
     36   * \warning Currently, any other usage of transpose() and adjoint() are not supported and will produce compilation errors.
     37   *
     38   * \sa class PartialPivLU, class FullPivLU
     39   */
     40 template<typename Derived>
     41 class SolverBase : public EigenBase<Derived>
     42 {
     43   public:
     44 
     45     typedef EigenBase<Derived> Base;
     46     typedef typename internal::traits<Derived>::Scalar Scalar;
     47     typedef Scalar CoeffReturnType;
     48 
     49     enum {
     50       RowsAtCompileTime = internal::traits<Derived>::RowsAtCompileTime,
     51       ColsAtCompileTime = internal::traits<Derived>::ColsAtCompileTime,
     52       SizeAtCompileTime = (internal::size_at_compile_time<internal::traits<Derived>::RowsAtCompileTime,
     53                                                           internal::traits<Derived>::ColsAtCompileTime>::ret),
     54       MaxRowsAtCompileTime = internal::traits<Derived>::MaxRowsAtCompileTime,
     55       MaxColsAtCompileTime = internal::traits<Derived>::MaxColsAtCompileTime,
     56       MaxSizeAtCompileTime = (internal::size_at_compile_time<internal::traits<Derived>::MaxRowsAtCompileTime,
     57                                                              internal::traits<Derived>::MaxColsAtCompileTime>::ret),
     58       IsVectorAtCompileTime = internal::traits<Derived>::MaxRowsAtCompileTime == 1
     59                            || internal::traits<Derived>::MaxColsAtCompileTime == 1
     60     };
     61 
     62     /** Default constructor */
     63     SolverBase()
     64     {}
     65 
     66     ~SolverBase()
     67     {}
     68 
     69     using Base::derived;
     70 
     71     /** \returns an expression of the solution x of \f$ A x = b \f$ using the current decomposition of A.
     72       */
     73     template<typename Rhs>
     74     inline const Solve<Derived, Rhs>
     75     solve(const MatrixBase<Rhs>& b) const
     76     {
     77       eigen_assert(derived().rows()==b.rows() && "solve(): invalid number of rows of the right hand side matrix b");
     78       return Solve<Derived, Rhs>(derived(), b.derived());
     79     }
     80 
     81     /** \internal the return type of transpose() */
     82     typedef typename internal::add_const<Transpose<const Derived> >::type ConstTransposeReturnType;
     83     /** \returns an expression of the transposed of the factored matrix.
     84       *
     85       * A typical usage is to solve for the transposed problem A^T x = b:
     86       * \code x = dec.transpose().solve(b); \endcode
     87       *
     88       * \sa adjoint(), solve()
     89       */
     90     inline ConstTransposeReturnType transpose() const
     91     {
     92       return ConstTransposeReturnType(derived());
     93     }
     94 
     95     /** \internal the return type of adjoint() */
     96     typedef typename internal::conditional<NumTraits<Scalar>::IsComplex,
     97                         CwiseUnaryOp<internal::scalar_conjugate_op<Scalar>, ConstTransposeReturnType>,
     98                         ConstTransposeReturnType
     99                      >::type AdjointReturnType;
    100     /** \returns an expression of the adjoint of the factored matrix
    101       *
    102       * A typical usage is to solve for the adjoint problem A' x = b:
    103       * \code x = dec.adjoint().solve(b); \endcode
    104       *
    105       * For real scalar types, this function is equivalent to transpose().
    106       *
    107       * \sa transpose(), solve()
    108       */
    109     inline AdjointReturnType adjoint() const
    110     {
    111       return AdjointReturnType(derived().transpose());
    112     }
    113 
    114   protected:
    115 };
    116 
    117 namespace internal {
    118 
    119 template<typename Derived>
    120 struct generic_xpr_base<Derived, MatrixXpr, SolverStorage>
    121 {
    122   typedef SolverBase<Derived> type;
    123 
    124 };
    125 
    126 } // end namespace internal
    127 
    128 } // end namespace Eigen
    129 
    130 #endif // EIGEN_SOLVERBASE_H
    131