cart-elc

Source code for CART-ELC
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Inverse.h (3503B)

      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2014-2019 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_INVERSE_H
     11 #define EIGEN_INVERSE_H
     12 
     13 namespace Eigen {
     14 
     15 template<typename XprType,typename StorageKind> class InverseImpl;
     16 
     17 namespace internal {
     18 
     19 template<typename XprType>
     20 struct traits<Inverse<XprType> >
     21   : traits<typename XprType::PlainObject>
     22 {
     23   typedef typename XprType::PlainObject PlainObject;
     24   typedef traits<PlainObject> BaseTraits;
     25   enum {
     26     Flags = BaseTraits::Flags & RowMajorBit
     27   };
     28 };
     29 
     30 } // end namespace internal
     31 
     32 /** \class Inverse
     33   *
     34   * \brief Expression of the inverse of another expression
     35   *
     36   * \tparam XprType the type of the expression we are taking the inverse
     37   *
     38   * This class represents an abstract expression of A.inverse()
     39   * and most of the time this is the only way it is used.
     40   *
     41   */
     42 template<typename XprType>
     43 class Inverse : public InverseImpl<XprType,typename internal::traits<XprType>::StorageKind>
     44 {
     45 public:
     46   typedef typename XprType::StorageIndex StorageIndex;
     47   typedef typename XprType::Scalar                            Scalar;
     48   typedef typename internal::ref_selector<XprType>::type      XprTypeNested;
     49   typedef typename internal::remove_all<XprTypeNested>::type  XprTypeNestedCleaned;
     50   typedef typename internal::ref_selector<Inverse>::type Nested;
     51   typedef typename internal::remove_all<XprType>::type NestedExpression;
     52 
     53   explicit EIGEN_DEVICE_FUNC Inverse(const XprType &xpr)
     54     : m_xpr(xpr)
     55   {}
     56 
     57   EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR  Index rows() const EIGEN_NOEXCEPT { return m_xpr.cols(); }
     58   EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR  Index cols() const EIGEN_NOEXCEPT { return m_xpr.rows(); }
     59 
     60   EIGEN_DEVICE_FUNC const XprTypeNestedCleaned& nestedExpression() const { return m_xpr; }
     61 
     62 protected:
     63   XprTypeNested m_xpr;
     64 };
     65 
     66 // Generic API dispatcher
     67 template<typename XprType, typename StorageKind>
     68 class InverseImpl
     69   : public internal::generic_xpr_base<Inverse<XprType> >::type
     70 {
     71 public:
     72   typedef typename internal::generic_xpr_base<Inverse<XprType> >::type Base;
     73   typedef typename XprType::Scalar Scalar;
     74 private:
     75 
     76   Scalar coeff(Index row, Index col) const;
     77   Scalar coeff(Index i) const;
     78 };
     79 
     80 namespace internal {
     81 
     82 /** \internal
     83   * \brief Default evaluator for Inverse expression.
     84   *
     85   * This default evaluator for Inverse expression simply evaluate the inverse into a temporary
     86   * by a call to internal::call_assignment_no_alias.
     87   * Therefore, inverse implementers only have to specialize Assignment<Dst,Inverse<...>, ...> for
     88   * there own nested expression.
     89   *
     90   * \sa class Inverse
     91   */
     92 template<typename ArgType>
     93 struct unary_evaluator<Inverse<ArgType> >
     94   : public evaluator<typename Inverse<ArgType>::PlainObject>
     95 {
     96   typedef Inverse<ArgType> InverseType;
     97   typedef typename InverseType::PlainObject PlainObject;
     98   typedef evaluator<PlainObject> Base;
     99 
    100   enum { Flags = Base::Flags | EvalBeforeNestingBit };
    101 
    102   unary_evaluator(const InverseType& inv_xpr)
    103     : m_result(inv_xpr.rows(), inv_xpr.cols())
    104   {
    105     ::new (static_cast<Base*>(this)) Base(m_result);
    106     internal::call_assignment_no_alias(m_result, inv_xpr);
    107   }
    108 
    109 protected:
    110   PlainObject m_result;
    111 };
    112 
    113 } // end namespace internal
    114 
    115 } // end namespace Eigen
    116 
    117 #endif // EIGEN_INVERSE_H