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 (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_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::PlainObject PlainObject; 48 typedef typename XprType::Scalar Scalar; 49 typedef typename internal::ref_selector<XprType>::type XprTypeNested; 50 typedef typename internal::remove_all<XprTypeNested>::type XprTypeNestedCleaned; 51 typedef typename internal::ref_selector<Inverse>::type Nested; 52 typedef typename internal::remove_all<XprType>::type NestedExpression; 53 54 explicit EIGEN_DEVICE_FUNC Inverse(const XprType &xpr) 55 : m_xpr(xpr) 56 {} 57 58 EIGEN_DEVICE_FUNC Index rows() const { return m_xpr.rows(); } 59 EIGEN_DEVICE_FUNC Index cols() const { return m_xpr.cols(); } 60 61 EIGEN_DEVICE_FUNC const XprTypeNestedCleaned& nestedExpression() const { return m_xpr; } 62 63 protected: 64 XprTypeNested m_xpr; 65 }; 66 67 // Generic API dispatcher 68 template<typename XprType, typename StorageKind> 69 class InverseImpl 70 : public internal::generic_xpr_base<Inverse<XprType> >::type 71 { 72 public: 73 typedef typename internal::generic_xpr_base<Inverse<XprType> >::type Base; 74 typedef typename XprType::Scalar Scalar; 75 private: 76 77 Scalar coeff(Index row, Index col) const; 78 Scalar coeff(Index i) const; 79 }; 80 81 namespace internal { 82 83 /** \internal 84 * \brief Default evaluator for Inverse expression. 85 * 86 * This default evaluator for Inverse expression simply evaluate the inverse into a temporary 87 * by a call to internal::call_assignment_no_alias. 88 * Therefore, inverse implementers only have to specialize Assignment<Dst,Inverse<...>, ...> for 89 * there own nested expression. 90 * 91 * \sa class Inverse 92 */ 93 template<typename ArgType> 94 struct unary_evaluator<Inverse<ArgType> > 95 : public evaluator<typename Inverse<ArgType>::PlainObject> 96 { 97 typedef Inverse<ArgType> InverseType; 98 typedef typename InverseType::PlainObject PlainObject; 99 typedef evaluator<PlainObject> Base; 100 101 enum { Flags = Base::Flags | EvalBeforeNestingBit }; 102 103 unary_evaluator(const InverseType& inv_xpr) 104 : m_result(inv_xpr.rows(), inv_xpr.cols()) 105 { 106 ::new (static_cast<Base*>(this)) Base(m_result); 107 internal::call_assignment_no_alias(m_result, inv_xpr); 108 } 109 110 protected: 111 PlainObject m_result; 112 }; 113 114 } // end namespace internal 115 116 } // end namespace Eigen 117 118 #endif // EIGEN_INVERSE_H 119
