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- // This file is part of Eigen, a lightweight C++ template library
- // for linear algebra.
- //
- // Copyright (C) 2009-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
- // Copyright (C) 2009-2010 Benoit Jacob <jacob.benoit.1@gmail.com>
- //
- // This Source Code Form is subject to the terms of the Mozilla
- // Public License v. 2.0. If a copy of the MPL was not distributed
- // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
- #ifndef EIGEN_RETURNBYVALUE_H
- #define EIGEN_RETURNBYVALUE_H
- namespace Eigen {
- namespace internal {
- template<typename Derived>
- struct traits<ReturnByValue<Derived> >
- : public traits<typename traits<Derived>::ReturnType>
- {
- enum {
- // We're disabling the DirectAccess because e.g. the constructor of
- // the Block-with-DirectAccess expression requires to have a coeffRef method.
- // Also, we don't want to have to implement the stride stuff.
- Flags = (traits<typename traits<Derived>::ReturnType>::Flags
- | EvalBeforeNestingBit) & ~DirectAccessBit
- };
- };
- /* The ReturnByValue object doesn't even have a coeff() method.
- * So the only way that nesting it in an expression can work, is by evaluating it into a plain matrix.
- * So internal::nested always gives the plain return matrix type.
- *
- * FIXME: I don't understand why we need this specialization: isn't this taken care of by the EvalBeforeNestingBit ??
- * Answer: EvalBeforeNestingBit should be deprecated since we have the evaluators
- */
- template<typename Derived,int n,typename PlainObject>
- struct nested_eval<ReturnByValue<Derived>, n, PlainObject>
- {
- typedef typename traits<Derived>::ReturnType type;
- };
- } // end namespace internal
- /** \class ReturnByValue
- * \ingroup Core_Module
- *
- */
- template<typename Derived> class ReturnByValue
- : public internal::dense_xpr_base< ReturnByValue<Derived> >::type, internal::no_assignment_operator
- {
- public:
- typedef typename internal::traits<Derived>::ReturnType ReturnType;
- typedef typename internal::dense_xpr_base<ReturnByValue>::type Base;
- EIGEN_DENSE_PUBLIC_INTERFACE(ReturnByValue)
- template<typename Dest>
- EIGEN_DEVICE_FUNC
- inline void evalTo(Dest& dst) const
- { static_cast<const Derived*>(this)->evalTo(dst); }
- EIGEN_DEVICE_FUNC inline Index rows() const { return static_cast<const Derived*>(this)->rows(); }
- EIGEN_DEVICE_FUNC inline Index cols() const { return static_cast<const Derived*>(this)->cols(); }
- #ifndef EIGEN_PARSED_BY_DOXYGEN
- #define Unusable YOU_ARE_TRYING_TO_ACCESS_A_SINGLE_COEFFICIENT_IN_A_SPECIAL_EXPRESSION_WHERE_THAT_IS_NOT_ALLOWED_BECAUSE_THAT_WOULD_BE_INEFFICIENT
- class Unusable{
- Unusable(const Unusable&) {}
- Unusable& operator=(const Unusable&) {return *this;}
- };
- const Unusable& coeff(Index) const { return *reinterpret_cast<const Unusable*>(this); }
- const Unusable& coeff(Index,Index) const { return *reinterpret_cast<const Unusable*>(this); }
- Unusable& coeffRef(Index) { return *reinterpret_cast<Unusable*>(this); }
- Unusable& coeffRef(Index,Index) { return *reinterpret_cast<Unusable*>(this); }
- #undef Unusable
- #endif
- };
- template<typename Derived>
- template<typename OtherDerived>
- Derived& DenseBase<Derived>::operator=(const ReturnByValue<OtherDerived>& other)
- {
- other.evalTo(derived());
- return derived();
- }
- namespace internal {
- // Expression is evaluated in a temporary; default implementation of Assignment is bypassed so that
- // when a ReturnByValue expression is assigned, the evaluator is not constructed.
- // TODO: Finalize port to new regime; ReturnByValue should not exist in the expression world
-
- template<typename Derived>
- struct evaluator<ReturnByValue<Derived> >
- : public evaluator<typename internal::traits<Derived>::ReturnType>
- {
- typedef ReturnByValue<Derived> XprType;
- typedef typename internal::traits<Derived>::ReturnType PlainObject;
- typedef evaluator<PlainObject> Base;
-
- EIGEN_DEVICE_FUNC explicit evaluator(const XprType& xpr)
- : m_result(xpr.rows(), xpr.cols())
- {
- ::new (static_cast<Base*>(this)) Base(m_result);
- xpr.evalTo(m_result);
- }
- protected:
- PlainObject m_result;
- };
- } // end namespace internal
- } // end namespace Eigen
- #endif // EIGEN_RETURNBYVALUE_H
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