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387 lines
13 KiB
C++
387 lines
13 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// Copyright (C) 2010-2011 Gael Guennebaud <gael.guennebaud@inria.fr>
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#ifndef EIGEN_TRANSPOSITIONS_H
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#define EIGEN_TRANSPOSITIONS_H
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namespace Eigen {
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template<typename Derived>
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class TranspositionsBase
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{
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typedef internal::traits<Derived> Traits;
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public:
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typedef typename Traits::IndicesType IndicesType;
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typedef typename IndicesType::Scalar StorageIndex;
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typedef Eigen::Index Index; ///< \deprecated since Eigen 3.3
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EIGEN_DEVICE_FUNC
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Derived& derived() { return *static_cast<Derived*>(this); }
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EIGEN_DEVICE_FUNC
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const Derived& derived() const { return *static_cast<const Derived*>(this); }
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/** Copies the \a other transpositions into \c *this */
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template<typename OtherDerived>
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Derived& operator=(const TranspositionsBase<OtherDerived>& other)
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{
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indices() = other.indices();
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return derived();
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}
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/** \returns the number of transpositions */
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EIGEN_DEVICE_FUNC
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Index size() const { return indices().size(); }
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/** \returns the number of rows of the equivalent permutation matrix */
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EIGEN_DEVICE_FUNC
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Index rows() const { return indices().size(); }
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/** \returns the number of columns of the equivalent permutation matrix */
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EIGEN_DEVICE_FUNC
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Index cols() const { return indices().size(); }
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/** Direct access to the underlying index vector */
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EIGEN_DEVICE_FUNC
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inline const StorageIndex& coeff(Index i) const { return indices().coeff(i); }
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/** Direct access to the underlying index vector */
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inline StorageIndex& coeffRef(Index i) { return indices().coeffRef(i); }
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/** Direct access to the underlying index vector */
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inline const StorageIndex& operator()(Index i) const { return indices()(i); }
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/** Direct access to the underlying index vector */
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inline StorageIndex& operator()(Index i) { return indices()(i); }
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/** Direct access to the underlying index vector */
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inline const StorageIndex& operator[](Index i) const { return indices()(i); }
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/** Direct access to the underlying index vector */
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inline StorageIndex& operator[](Index i) { return indices()(i); }
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/** const version of indices(). */
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EIGEN_DEVICE_FUNC
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const IndicesType& indices() const { return derived().indices(); }
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/** \returns a reference to the stored array representing the transpositions. */
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EIGEN_DEVICE_FUNC
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IndicesType& indices() { return derived().indices(); }
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/** Resizes to given size. */
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inline void resize(Index newSize)
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{
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indices().resize(newSize);
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}
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/** Sets \c *this to represents an identity transformation */
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void setIdentity()
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{
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for(StorageIndex i = 0; i < indices().size(); ++i)
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coeffRef(i) = i;
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}
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// FIXME: do we want such methods ?
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// might be useful when the target matrix expression is complex, e.g.:
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// object.matrix().block(..,..,..,..) = trans * object.matrix().block(..,..,..,..);
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/*
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template<typename MatrixType>
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void applyForwardToRows(MatrixType& mat) const
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{
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for(Index k=0 ; k<size() ; ++k)
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if(m_indices(k)!=k)
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mat.row(k).swap(mat.row(m_indices(k)));
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}
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template<typename MatrixType>
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void applyBackwardToRows(MatrixType& mat) const
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{
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for(Index k=size()-1 ; k>=0 ; --k)
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if(m_indices(k)!=k)
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mat.row(k).swap(mat.row(m_indices(k)));
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}
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*/
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/** \returns the inverse transformation */
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inline Transpose<TranspositionsBase> inverse() const
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{ return Transpose<TranspositionsBase>(derived()); }
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/** \returns the tranpose transformation */
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inline Transpose<TranspositionsBase> transpose() const
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{ return Transpose<TranspositionsBase>(derived()); }
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protected:
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};
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namespace internal {
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template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename _StorageIndex>
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struct traits<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,_StorageIndex> >
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: traits<PermutationMatrix<SizeAtCompileTime,MaxSizeAtCompileTime,_StorageIndex> >
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{
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typedef Matrix<_StorageIndex, SizeAtCompileTime, 1, 0, MaxSizeAtCompileTime, 1> IndicesType;
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typedef TranspositionsStorage StorageKind;
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};
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}
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/** \class Transpositions
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* \ingroup Core_Module
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*
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* \brief Represents a sequence of transpositions (row/column interchange)
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*
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* \tparam SizeAtCompileTime the number of transpositions, or Dynamic
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* \tparam MaxSizeAtCompileTime the maximum number of transpositions, or Dynamic. This optional parameter defaults to SizeAtCompileTime. Most of the time, you should not have to specify it.
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*
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* This class represents a permutation transformation as a sequence of \em n transpositions
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* \f$[T_{n-1} \ldots T_{i} \ldots T_{0}]\f$. It is internally stored as a vector of integers \c indices.
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* Each transposition \f$ T_{i} \f$ applied on the left of a matrix (\f$ T_{i} M\f$) interchanges
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* the rows \c i and \c indices[i] of the matrix \c M.
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* A transposition applied on the right (e.g., \f$ M T_{i}\f$) yields a column interchange.
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*
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* Compared to the class PermutationMatrix, such a sequence of transpositions is what is
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* computed during a decomposition with pivoting, and it is faster when applying the permutation in-place.
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*
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* To apply a sequence of transpositions to a matrix, simply use the operator * as in the following example:
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* \code
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* Transpositions tr;
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* MatrixXf mat;
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* mat = tr * mat;
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* \endcode
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* In this example, we detect that the matrix appears on both side, and so the transpositions
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* are applied in-place without any temporary or extra copy.
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*
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* \sa class PermutationMatrix
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*/
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template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename _StorageIndex>
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class Transpositions : public TranspositionsBase<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,_StorageIndex> >
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{
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typedef internal::traits<Transpositions> Traits;
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public:
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typedef TranspositionsBase<Transpositions> Base;
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typedef typename Traits::IndicesType IndicesType;
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typedef typename IndicesType::Scalar StorageIndex;
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inline Transpositions() {}
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/** Copy constructor. */
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template<typename OtherDerived>
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inline Transpositions(const TranspositionsBase<OtherDerived>& other)
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: m_indices(other.indices()) {}
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/** Generic constructor from expression of the transposition indices. */
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template<typename Other>
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explicit inline Transpositions(const MatrixBase<Other>& indices) : m_indices(indices)
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{}
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/** Copies the \a other transpositions into \c *this */
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template<typename OtherDerived>
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Transpositions& operator=(const TranspositionsBase<OtherDerived>& other)
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{
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return Base::operator=(other);
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}
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/** Constructs an uninitialized permutation matrix of given size.
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*/
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inline Transpositions(Index size) : m_indices(size)
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{}
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/** const version of indices(). */
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EIGEN_DEVICE_FUNC
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const IndicesType& indices() const { return m_indices; }
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/** \returns a reference to the stored array representing the transpositions. */
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EIGEN_DEVICE_FUNC
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IndicesType& indices() { return m_indices; }
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protected:
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IndicesType m_indices;
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};
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namespace internal {
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template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename _StorageIndex, int _PacketAccess>
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struct traits<Map<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,_StorageIndex>,_PacketAccess> >
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: traits<PermutationMatrix<SizeAtCompileTime,MaxSizeAtCompileTime,_StorageIndex> >
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{
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typedef Map<const Matrix<_StorageIndex,SizeAtCompileTime,1,0,MaxSizeAtCompileTime,1>, _PacketAccess> IndicesType;
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typedef _StorageIndex StorageIndex;
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typedef TranspositionsStorage StorageKind;
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};
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}
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template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename _StorageIndex, int PacketAccess>
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class Map<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,_StorageIndex>,PacketAccess>
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: public TranspositionsBase<Map<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,_StorageIndex>,PacketAccess> >
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{
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typedef internal::traits<Map> Traits;
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public:
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typedef TranspositionsBase<Map> Base;
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typedef typename Traits::IndicesType IndicesType;
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typedef typename IndicesType::Scalar StorageIndex;
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explicit inline Map(const StorageIndex* indicesPtr)
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: m_indices(indicesPtr)
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{}
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inline Map(const StorageIndex* indicesPtr, Index size)
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: m_indices(indicesPtr,size)
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{}
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/** Copies the \a other transpositions into \c *this */
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template<typename OtherDerived>
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Map& operator=(const TranspositionsBase<OtherDerived>& other)
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{
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return Base::operator=(other);
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}
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#ifndef EIGEN_PARSED_BY_DOXYGEN
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/** This is a special case of the templated operator=. Its purpose is to
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* prevent a default operator= from hiding the templated operator=.
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*/
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Map& operator=(const Map& other)
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{
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m_indices = other.m_indices;
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return *this;
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}
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#endif
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/** const version of indices(). */
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EIGEN_DEVICE_FUNC
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const IndicesType& indices() const { return m_indices; }
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/** \returns a reference to the stored array representing the transpositions. */
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EIGEN_DEVICE_FUNC
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IndicesType& indices() { return m_indices; }
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protected:
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IndicesType m_indices;
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};
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namespace internal {
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template<typename _IndicesType>
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struct traits<TranspositionsWrapper<_IndicesType> >
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: traits<PermutationWrapper<_IndicesType> >
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{
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typedef TranspositionsStorage StorageKind;
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};
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}
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template<typename _IndicesType>
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class TranspositionsWrapper
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: public TranspositionsBase<TranspositionsWrapper<_IndicesType> >
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{
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typedef internal::traits<TranspositionsWrapper> Traits;
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public:
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typedef TranspositionsBase<TranspositionsWrapper> Base;
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typedef typename Traits::IndicesType IndicesType;
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typedef typename IndicesType::Scalar StorageIndex;
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explicit inline TranspositionsWrapper(IndicesType& indices)
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: m_indices(indices)
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{}
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/** Copies the \a other transpositions into \c *this */
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template<typename OtherDerived>
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TranspositionsWrapper& operator=(const TranspositionsBase<OtherDerived>& other)
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{
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return Base::operator=(other);
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}
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/** const version of indices(). */
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EIGEN_DEVICE_FUNC
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const IndicesType& indices() const { return m_indices; }
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/** \returns a reference to the stored array representing the transpositions. */
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EIGEN_DEVICE_FUNC
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IndicesType& indices() { return m_indices; }
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protected:
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typename IndicesType::Nested m_indices;
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};
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/** \returns the \a matrix with the \a transpositions applied to the columns.
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*/
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template<typename MatrixDerived, typename TranspositionsDerived>
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EIGEN_DEVICE_FUNC
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const Product<MatrixDerived, TranspositionsDerived, AliasFreeProduct>
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operator*(const MatrixBase<MatrixDerived> &matrix,
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const TranspositionsBase<TranspositionsDerived>& transpositions)
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{
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return Product<MatrixDerived, TranspositionsDerived, AliasFreeProduct>
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(matrix.derived(), transpositions.derived());
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}
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/** \returns the \a matrix with the \a transpositions applied to the rows.
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*/
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template<typename TranspositionsDerived, typename MatrixDerived>
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EIGEN_DEVICE_FUNC
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const Product<TranspositionsDerived, MatrixDerived, AliasFreeProduct>
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operator*(const TranspositionsBase<TranspositionsDerived> &transpositions,
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const MatrixBase<MatrixDerived>& matrix)
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{
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return Product<TranspositionsDerived, MatrixDerived, AliasFreeProduct>
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(transpositions.derived(), matrix.derived());
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}
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// Template partial specialization for transposed/inverse transpositions
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namespace internal {
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template<typename Derived>
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struct traits<Transpose<TranspositionsBase<Derived> > >
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: traits<Derived>
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{};
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} // end namespace internal
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template<typename TranspositionsDerived>
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class Transpose<TranspositionsBase<TranspositionsDerived> >
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{
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typedef TranspositionsDerived TranspositionType;
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typedef typename TranspositionType::IndicesType IndicesType;
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public:
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explicit Transpose(const TranspositionType& t) : m_transpositions(t) {}
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EIGEN_DEVICE_FUNC
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Index size() const { return m_transpositions.size(); }
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EIGEN_DEVICE_FUNC
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Index rows() const { return m_transpositions.size(); }
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EIGEN_DEVICE_FUNC
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Index cols() const { return m_transpositions.size(); }
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/** \returns the \a matrix with the inverse transpositions applied to the columns.
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*/
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template<typename OtherDerived> friend
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const Product<OtherDerived, Transpose, AliasFreeProduct>
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operator*(const MatrixBase<OtherDerived>& matrix, const Transpose& trt)
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{
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return Product<OtherDerived, Transpose, AliasFreeProduct>(matrix.derived(), trt);
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}
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/** \returns the \a matrix with the inverse transpositions applied to the rows.
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*/
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template<typename OtherDerived>
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const Product<Transpose, OtherDerived, AliasFreeProduct>
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operator*(const MatrixBase<OtherDerived>& matrix) const
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{
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return Product<Transpose, OtherDerived, AliasFreeProduct>(*this, matrix.derived());
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}
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EIGEN_DEVICE_FUNC
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const TranspositionType& nestedExpression() const { return m_transpositions; }
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protected:
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const TranspositionType& m_transpositions;
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};
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} // end namespace Eigen
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#endif // EIGEN_TRANSPOSITIONS_H
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