diff options
Diffstat (limited to 'src/Eigen/src/Core/Transpositions.h')
| -rw-r--r-- | src/Eigen/src/Core/Transpositions.h | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/src/Eigen/src/Core/Transpositions.h b/src/Eigen/src/Core/Transpositions.h new file mode 100644 index 0000000..e4ba075 --- /dev/null +++ b/src/Eigen/src/Core/Transpositions.h @@ -0,0 +1,436 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// Copyright (C) 2010-2011 Gael Guennebaud <gael.guennebaud@inria.fr> +// +// 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_TRANSPOSITIONS_H +#define EIGEN_TRANSPOSITIONS_H + +namespace Eigen { + +/** \class Transpositions + * \ingroup Core_Module + * + * \brief Represents a sequence of transpositions (row/column interchange) + * + * \param SizeAtCompileTime the number of transpositions, or Dynamic + * \param 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. + * + * This class represents a permutation transformation as a sequence of \em n transpositions + * \f$[T_{n-1} \ldots T_{i} \ldots T_{0}]\f$. It is internally stored as a vector of integers \c indices. + * Each transposition \f$ T_{i} \f$ applied on the left of a matrix (\f$ T_{i} M\f$) interchanges + * the rows \c i and \c indices[i] of the matrix \c M. + * A transposition applied on the right (e.g., \f$ M T_{i}\f$) yields a column interchange. + * + * Compared to the class PermutationMatrix, such a sequence of transpositions is what is + * computed during a decomposition with pivoting, and it is faster when applying the permutation in-place. + * + * To apply a sequence of transpositions to a matrix, simply use the operator * as in the following example: + * \code + * Transpositions tr; + * MatrixXf mat; + * mat = tr * mat; + * \endcode + * In this example, we detect that the matrix appears on both side, and so the transpositions + * are applied in-place without any temporary or extra copy. + * + * \sa class PermutationMatrix + */ + +namespace internal { +template<typename TranspositionType, typename MatrixType, int Side, bool Transposed=false> struct transposition_matrix_product_retval; +} + +template<typename Derived> +class TranspositionsBase +{ + typedef internal::traits<Derived> Traits; + + public: + + typedef typename Traits::IndicesType IndicesType; + typedef typename IndicesType::Scalar Index; + + Derived& derived() { return *static_cast<Derived*>(this); } + const Derived& derived() const { return *static_cast<const Derived*>(this); } + + /** Copies the \a other transpositions into \c *this */ + template<typename OtherDerived> + Derived& operator=(const TranspositionsBase<OtherDerived>& other) + { + indices() = other.indices(); + return derived(); + } + + #ifndef EIGEN_PARSED_BY_DOXYGEN + /** This is a special case of the templated operator=. Its purpose is to + * prevent a default operator= from hiding the templated operator=. + */ + Derived& operator=(const TranspositionsBase& other) + { + indices() = other.indices(); + return derived(); + } + #endif + + /** \returns the number of transpositions */ + inline Index size() const { return indices().size(); } + + /** Direct access to the underlying index vector */ + inline const Index& coeff(Index i) const { return indices().coeff(i); } + /** Direct access to the underlying index vector */ + inline Index& coeffRef(Index i) { return indices().coeffRef(i); } + /** Direct access to the underlying index vector */ + inline const Index& operator()(Index i) const { return indices()(i); } + /** Direct access to the underlying index vector */ + inline Index& operator()(Index i) { return indices()(i); } + /** Direct access to the underlying index vector */ + inline const Index& operator[](Index i) const { return indices()(i); } + /** Direct access to the underlying index vector */ + inline Index& operator[](Index i) { return indices()(i); } + + /** const version of indices(). */ + const IndicesType& indices() const { return derived().indices(); } + /** \returns a reference to the stored array representing the transpositions. */ + IndicesType& indices() { return derived().indices(); } + + /** Resizes to given size. */ + inline void resize(int newSize) + { + indices().resize(newSize); + } + + /** Sets \c *this to represents an identity transformation */ + void setIdentity() + { + for(int i = 0; i < indices().size(); ++i) + coeffRef(i) = i; + } + + // FIXME: do we want such methods ? + // might be usefull when the target matrix expression is complex, e.g.: + // object.matrix().block(..,..,..,..) = trans * object.matrix().block(..,..,..,..); + /* + template<typename MatrixType> + void applyForwardToRows(MatrixType& mat) const + { + for(Index k=0 ; k<size() ; ++k) + if(m_indices(k)!=k) + mat.row(k).swap(mat.row(m_indices(k))); + } + + template<typename MatrixType> + void applyBackwardToRows(MatrixType& mat) const + { + for(Index k=size()-1 ; k>=0 ; --k) + if(m_indices(k)!=k) + mat.row(k).swap(mat.row(m_indices(k))); + } + */ + + /** \returns the inverse transformation */ + inline Transpose<TranspositionsBase> inverse() const + { return Transpose<TranspositionsBase>(derived()); } + + /** \returns the tranpose transformation */ + inline Transpose<TranspositionsBase> transpose() const + { return Transpose<TranspositionsBase>(derived()); } + + protected: +}; + +namespace internal { +template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename IndexType> +struct traits<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,IndexType> > +{ + typedef IndexType Index; + typedef Matrix<Index, SizeAtCompileTime, 1, 0, MaxSizeAtCompileTime, 1> IndicesType; +}; +} + +template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename IndexType> +class Transpositions : public TranspositionsBase<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,IndexType> > +{ + typedef internal::traits<Transpositions> Traits; + public: + + typedef TranspositionsBase<Transpositions> Base; + typedef typename Traits::IndicesType IndicesType; + typedef typename IndicesType::Scalar Index; + + inline Transpositions() {} + + /** Copy constructor. */ + template<typename OtherDerived> + inline Transpositions(const TranspositionsBase<OtherDerived>& other) + : m_indices(other.indices()) {} + + #ifndef EIGEN_PARSED_BY_DOXYGEN + /** Standard copy constructor. Defined only to prevent a default copy constructor + * from hiding the other templated constructor */ + inline Transpositions(const Transpositions& other) : m_indices(other.indices()) {} + #endif + + /** Generic constructor from expression of the transposition indices. */ + template<typename Other> + explicit inline Transpositions(const MatrixBase<Other>& a_indices) : m_indices(a_indices) + {} + + /** Copies the \a other transpositions into \c *this */ + template<typename OtherDerived> + Transpositions& operator=(const TranspositionsBase<OtherDerived>& other) + { + return Base::operator=(other); + } + + #ifndef EIGEN_PARSED_BY_DOXYGEN + /** This is a special case of the templated operator=. Its purpose is to + * prevent a default operator= from hiding the templated operator=. + */ + Transpositions& operator=(const Transpositions& other) + { + m_indices = other.m_indices; + return *this; + } + #endif + + /** Constructs an uninitialized permutation matrix of given size. + */ + inline Transpositions(Index size) : m_indices(size) + {} + + /** const version of indices(). */ + const IndicesType& indices() const { return m_indices; } + /** \returns a reference to the stored array representing the transpositions. */ + IndicesType& indices() { return m_indices; } + + protected: + + IndicesType m_indices; +}; + + +namespace internal { +template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename IndexType, int _PacketAccess> +struct traits<Map<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,IndexType>,_PacketAccess> > +{ + typedef IndexType Index; + typedef Map<const Matrix<Index,SizeAtCompileTime,1,0,MaxSizeAtCompileTime,1>, _PacketAccess> IndicesType; +}; +} + +template<int SizeAtCompileTime, int MaxSizeAtCompileTime, typename IndexType, int PacketAccess> +class Map<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,IndexType>,PacketAccess> + : public TranspositionsBase<Map<Transpositions<SizeAtCompileTime,MaxSizeAtCompileTime,IndexType>,PacketAccess> > +{ + typedef internal::traits<Map> Traits; + public: + + typedef TranspositionsBase<Map> Base; + typedef typename Traits::IndicesType IndicesType; + typedef typename IndicesType::Scalar Index; + + inline Map(const Index* indicesPtr) + : m_indices(indicesPtr) + {} + + inline Map(const Index* indicesPtr, Index size) + : m_indices(indicesPtr,size) + {} + + /** Copies the \a other transpositions into \c *this */ + template<typename OtherDerived> + Map& operator=(const TranspositionsBase<OtherDerived>& other) + { + return Base::operator=(other); + } + + #ifndef EIGEN_PARSED_BY_DOXYGEN + /** This is a special case of the templated operator=. Its purpose is to + * prevent a default operator= from hiding the templated operator=. + */ + Map& operator=(const Map& other) + { + m_indices = other.m_indices; + return *this; + } + #endif + + /** const version of indices(). */ + const IndicesType& indices() const { return m_indices; } + + /** \returns a reference to the stored array representing the transpositions. */ + IndicesType& indices() { return m_indices; } + + protected: + + IndicesType m_indices; +}; + +namespace internal { +template<typename _IndicesType> +struct traits<TranspositionsWrapper<_IndicesType> > +{ + typedef typename _IndicesType::Scalar Index; + typedef _IndicesType IndicesType; +}; +} + +template<typename _IndicesType> +class TranspositionsWrapper + : public TranspositionsBase<TranspositionsWrapper<_IndicesType> > +{ + typedef internal::traits<TranspositionsWrapper> Traits; + public: + + typedef TranspositionsBase<TranspositionsWrapper> Base; + typedef typename Traits::IndicesType IndicesType; + typedef typename IndicesType::Scalar Index; + + inline TranspositionsWrapper(IndicesType& a_indices) + : m_indices(a_indices) + {} + + /** Copies the \a other transpositions into \c *this */ + template<typename OtherDerived> + TranspositionsWrapper& operator=(const TranspositionsBase<OtherDerived>& other) + { + return Base::operator=(other); + } + + #ifndef EIGEN_PARSED_BY_DOXYGEN + /** This is a special case of the templated operator=. Its purpose is to + * prevent a default operator= from hiding the templated operator=. + */ + TranspositionsWrapper& operator=(const TranspositionsWrapper& other) + { + m_indices = other.m_indices; + return *this; + } + #endif + + /** const version of indices(). */ + const IndicesType& indices() const { return m_indices; } + + /** \returns a reference to the stored array representing the transpositions. */ + IndicesType& indices() { return m_indices; } + + protected: + + const typename IndicesType::Nested m_indices; +}; + +/** \returns the \a matrix with the \a transpositions applied to the columns. + */ +template<typename Derived, typename TranspositionsDerived> +inline const internal::transposition_matrix_product_retval<TranspositionsDerived, Derived, OnTheRight> +operator*(const MatrixBase<Derived>& matrix, + const TranspositionsBase<TranspositionsDerived> &transpositions) +{ + return internal::transposition_matrix_product_retval + <TranspositionsDerived, Derived, OnTheRight> + (transpositions.derived(), matrix.derived()); +} + +/** \returns the \a matrix with the \a transpositions applied to the rows. + */ +template<typename Derived, typename TranspositionDerived> +inline const internal::transposition_matrix_product_retval + <TranspositionDerived, Derived, OnTheLeft> +operator*(const TranspositionsBase<TranspositionDerived> &transpositions, + const MatrixBase<Derived>& matrix) +{ + return internal::transposition_matrix_product_retval + <TranspositionDerived, Derived, OnTheLeft> + (transpositions.derived(), matrix.derived()); +} + +namespace internal { + +template<typename TranspositionType, typename MatrixType, int Side, bool Transposed> +struct traits<transposition_matrix_product_retval<TranspositionType, MatrixType, Side, Transposed> > +{ + typedef typename MatrixType::PlainObject ReturnType; +}; + +template<typename TranspositionType, typename MatrixType, int Side, bool Transposed> +struct transposition_matrix_product_retval + : public ReturnByValue<transposition_matrix_product_retval<TranspositionType, MatrixType, Side, Transposed> > +{ + typedef typename remove_all<typename MatrixType::Nested>::type MatrixTypeNestedCleaned; + typedef typename TranspositionType::Index Index; + + transposition_matrix_product_retval(const TranspositionType& tr, const MatrixType& matrix) + : m_transpositions(tr), m_matrix(matrix) + {} + + inline int rows() const { return m_matrix.rows(); } + inline int cols() const { return m_matrix.cols(); } + + template<typename Dest> inline void evalTo(Dest& dst) const + { + const int size = m_transpositions.size(); + Index j = 0; + + if(!(is_same<MatrixTypeNestedCleaned,Dest>::value && extract_data(dst) == extract_data(m_matrix))) + dst = m_matrix; + + for(int k=(Transposed?size-1:0) ; Transposed?k>=0:k<size ; Transposed?--k:++k) + if((j=m_transpositions.coeff(k))!=k) + { + if(Side==OnTheLeft) + dst.row(k).swap(dst.row(j)); + else if(Side==OnTheRight) + dst.col(k).swap(dst.col(j)); + } + } + + protected: + const TranspositionType& m_transpositions; + typename MatrixType::Nested m_matrix; +}; + +} // end namespace internal + +/* Template partial specialization for transposed/inverse transpositions */ + +template<typename TranspositionsDerived> +class Transpose<TranspositionsBase<TranspositionsDerived> > +{ + typedef TranspositionsDerived TranspositionType; + typedef typename TranspositionType::IndicesType IndicesType; + public: + + Transpose(const TranspositionType& t) : m_transpositions(t) {} + + inline int size() const { return m_transpositions.size(); } + + /** \returns the \a matrix with the inverse transpositions applied to the columns. + */ + template<typename Derived> friend + inline const internal::transposition_matrix_product_retval<TranspositionType, Derived, OnTheRight, true> + operator*(const MatrixBase<Derived>& matrix, const Transpose& trt) + { + return internal::transposition_matrix_product_retval<TranspositionType, Derived, OnTheRight, true>(trt.m_transpositions, matrix.derived()); + } + + /** \returns the \a matrix with the inverse transpositions applied to the rows. + */ + template<typename Derived> + inline const internal::transposition_matrix_product_retval<TranspositionType, Derived, OnTheLeft, true> + operator*(const MatrixBase<Derived>& matrix) const + { + return internal::transposition_matrix_product_retval<TranspositionType, Derived, OnTheLeft, true>(m_transpositions, matrix.derived()); + } + + protected: + const TranspositionType& m_transpositions; +}; + +} // end namespace Eigen + +#endif // EIGEN_TRANSPOSITIONS_H |