diff options
Diffstat (limited to 'third_party/eigen3/Eigen/src/Householder')
3 files changed, 680 insertions, 0 deletions
diff --git a/third_party/eigen3/Eigen/src/Householder/BlockHouseholder.h b/third_party/eigen3/Eigen/src/Householder/BlockHouseholder.h new file mode 100644 index 0000000000..60dbea5f56 --- /dev/null +++ b/third_party/eigen3/Eigen/src/Householder/BlockHouseholder.h @@ -0,0 +1,68 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// Copyright (C) 2010 Vincent Lejeune +// Copyright (C) 2010 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_BLOCK_HOUSEHOLDER_H +#define EIGEN_BLOCK_HOUSEHOLDER_H + +// This file contains some helper function to deal with block householder reflectors + +namespace Eigen { + +namespace internal { + +/** \internal */ +template<typename TriangularFactorType,typename VectorsType,typename CoeffsType> +void make_block_householder_triangular_factor(TriangularFactorType& triFactor, const VectorsType& vectors, const CoeffsType& hCoeffs) +{ + typedef typename TriangularFactorType::Index Index; + typedef typename VectorsType::Scalar Scalar; + const Index nbVecs = vectors.cols(); + eigen_assert(triFactor.rows() == nbVecs && triFactor.cols() == nbVecs && vectors.rows()>=nbVecs); + + for(Index i = 0; i < nbVecs; i++) + { + Index rs = vectors.rows() - i; + Scalar Vii = vectors(i,i); + vectors.const_cast_derived().coeffRef(i,i) = Scalar(1); + triFactor.col(i).head(i).noalias() = -hCoeffs(i) * vectors.block(i, 0, rs, i).adjoint() + * vectors.col(i).tail(rs); + vectors.const_cast_derived().coeffRef(i, i) = Vii; + // FIXME add .noalias() once the triangular product can work inplace + triFactor.col(i).head(i) = triFactor.block(0,0,i,i).template triangularView<Upper>() + * triFactor.col(i).head(i); + triFactor(i,i) = hCoeffs(i); + } +} + +/** \internal */ +template<typename MatrixType,typename VectorsType,typename CoeffsType> +void apply_block_householder_on_the_left(MatrixType& mat, const VectorsType& vectors, const CoeffsType& hCoeffs) +{ + typedef typename MatrixType::Index Index; + enum { TFactorSize = MatrixType::ColsAtCompileTime }; + Index nbVecs = vectors.cols(); + Matrix<typename MatrixType::Scalar, TFactorSize, TFactorSize, ColMajor> T(nbVecs,nbVecs); + make_block_householder_triangular_factor(T, vectors, hCoeffs); + + const TriangularView<const VectorsType, UnitLower>& V(vectors); + + // A -= V T V^* A + Matrix<typename MatrixType::Scalar,VectorsType::ColsAtCompileTime,MatrixType::ColsAtCompileTime,0, + VectorsType::MaxColsAtCompileTime,MatrixType::MaxColsAtCompileTime> tmp = V.adjoint() * mat; + // FIXME add .noalias() once the triangular product can work inplace + tmp = T.template triangularView<Upper>().adjoint() * tmp; + mat.noalias() -= V * tmp; +} + +} // end namespace internal + +} // end namespace Eigen + +#endif // EIGEN_BLOCK_HOUSEHOLDER_H diff --git a/third_party/eigen3/Eigen/src/Householder/Householder.h b/third_party/eigen3/Eigen/src/Householder/Householder.h new file mode 100644 index 0000000000..32112af9bf --- /dev/null +++ b/third_party/eigen3/Eigen/src/Householder/Householder.h @@ -0,0 +1,171 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// Copyright (C) 2010 Benoit Jacob <jacob.benoit.1@gmail.com> +// Copyright (C) 2009 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_HOUSEHOLDER_H +#define EIGEN_HOUSEHOLDER_H + +namespace Eigen { + +namespace internal { +template<int n> struct decrement_size +{ + enum { + ret = n==Dynamic ? n : n-1 + }; +}; +} + +/** Computes the elementary reflector H such that: + * \f$ H *this = [ beta 0 ... 0]^T \f$ + * where the transformation H is: + * \f$ H = I - tau v v^*\f$ + * and the vector v is: + * \f$ v^T = [1 essential^T] \f$ + * + * The essential part of the vector \c v is stored in *this. + * + * On output: + * \param tau the scaling factor of the Householder transformation + * \param beta the result of H * \c *this + * + * \sa MatrixBase::makeHouseholder(), MatrixBase::applyHouseholderOnTheLeft(), + * MatrixBase::applyHouseholderOnTheRight() + */ +template<typename Derived> +void MatrixBase<Derived>::makeHouseholderInPlace(Scalar& tau, RealScalar& beta) +{ + VectorBlock<Derived, internal::decrement_size<Base::SizeAtCompileTime>::ret> essentialPart(derived(), 1, size()-1); + makeHouseholder(essentialPart, tau, beta); +} + +/** Computes the elementary reflector H such that: + * \f$ H *this = [ beta 0 ... 0]^T \f$ + * where the transformation H is: + * \f$ H = I - tau v v^*\f$ + * and the vector v is: + * \f$ v^T = [1 essential^T] \f$ + * + * On output: + * \param essential the essential part of the vector \c v + * \param tau the scaling factor of the Householder transformation + * \param beta the result of H * \c *this + * + * \sa MatrixBase::makeHouseholderInPlace(), MatrixBase::applyHouseholderOnTheLeft(), + * MatrixBase::applyHouseholderOnTheRight() + */ +template<typename Derived> +template<typename EssentialPart> +void MatrixBase<Derived>::makeHouseholder( + EssentialPart& essential, + Scalar& tau, + RealScalar& beta) const +{ + using std::sqrt; + using numext::conj; + + EIGEN_STATIC_ASSERT_VECTOR_ONLY(EssentialPart) + VectorBlock<const Derived, EssentialPart::SizeAtCompileTime> tail(derived(), 1, size()-1); + + RealScalar tailSqNorm = size()==1 ? RealScalar(0) : tail.squaredNorm(); + Scalar c0 = coeff(0); + + if(tailSqNorm == RealScalar(0) && numext::imag(c0)==RealScalar(0)) + { + tau = RealScalar(0); + beta = numext::real(c0); + essential.setZero(); + } + else + { + beta = sqrt(numext::abs2(c0) + tailSqNorm); + if (numext::real(c0)>=RealScalar(0)) + beta = -beta; + essential = tail / (c0 - beta); + tau = conj((beta - c0) / beta); + } +} + +/** Apply the elementary reflector H given by + * \f$ H = I - tau v v^*\f$ + * with + * \f$ v^T = [1 essential^T] \f$ + * from the left to a vector or matrix. + * + * On input: + * \param essential the essential part of the vector \c v + * \param tau the scaling factor of the Householder transformation + * \param workspace a pointer to working space with at least + * this->cols() * essential.size() entries + * + * \sa MatrixBase::makeHouseholder(), MatrixBase::makeHouseholderInPlace(), + * MatrixBase::applyHouseholderOnTheRight() + */ +template<typename Derived> +template<typename EssentialPart> +void MatrixBase<Derived>::applyHouseholderOnTheLeft( + const EssentialPart& essential, + const Scalar& tau, + Scalar* workspace) +{ + if(rows() == 1) + { + *this *= Scalar(1)-tau; + } + else + { + Map<typename internal::plain_row_type<PlainObject>::type> tmp(workspace,cols()); + Block<Derived, EssentialPart::SizeAtCompileTime, Derived::ColsAtCompileTime> bottom(derived(), 1, 0, rows()-1, cols()); + tmp.noalias() = essential.adjoint() * bottom; + tmp += this->row(0); + this->row(0) -= tau * tmp; + bottom.noalias() -= tau * essential * tmp; + } +} + +/** Apply the elementary reflector H given by + * \f$ H = I - tau v v^*\f$ + * with + * \f$ v^T = [1 essential^T] \f$ + * from the right to a vector or matrix. + * + * On input: + * \param essential the essential part of the vector \c v + * \param tau the scaling factor of the Householder transformation + * \param workspace a pointer to working space with at least + * this->cols() * essential.size() entries + * + * \sa MatrixBase::makeHouseholder(), MatrixBase::makeHouseholderInPlace(), + * MatrixBase::applyHouseholderOnTheLeft() + */ +template<typename Derived> +template<typename EssentialPart> +void MatrixBase<Derived>::applyHouseholderOnTheRight( + const EssentialPart& essential, + const Scalar& tau, + Scalar* workspace) +{ + if(cols() == 1) + { + *this *= Scalar(1)-tau; + } + else + { + Map<typename internal::plain_col_type<PlainObject>::type> tmp(workspace,rows()); + Block<Derived, Derived::RowsAtCompileTime, EssentialPart::SizeAtCompileTime> right(derived(), 0, 1, rows(), cols()-1); + tmp.noalias() = right * essential.conjugate(); + tmp += this->col(0); + this->col(0) -= tau * tmp; + right.noalias() -= tau * tmp * essential.transpose(); + } +} + +} // end namespace Eigen + +#endif // EIGEN_HOUSEHOLDER_H diff --git a/third_party/eigen3/Eigen/src/Householder/HouseholderSequence.h b/third_party/eigen3/Eigen/src/Householder/HouseholderSequence.h new file mode 100644 index 0000000000..d800ca1fa4 --- /dev/null +++ b/third_party/eigen3/Eigen/src/Householder/HouseholderSequence.h @@ -0,0 +1,441 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// Copyright (C) 2009 Gael Guennebaud <gael.guennebaud@inria.fr> +// Copyright (C) 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_HOUSEHOLDER_SEQUENCE_H +#define EIGEN_HOUSEHOLDER_SEQUENCE_H + +namespace Eigen { + +/** \ingroup Householder_Module + * \householder_module + * \class HouseholderSequence + * \brief Sequence of Householder reflections acting on subspaces with decreasing size + * \tparam VectorsType type of matrix containing the Householder vectors + * \tparam CoeffsType type of vector containing the Householder coefficients + * \tparam Side either OnTheLeft (the default) or OnTheRight + * + * This class represents a product sequence of Householder reflections where the first Householder reflection + * acts on the whole space, the second Householder reflection leaves the one-dimensional subspace spanned by + * the first unit vector invariant, the third Householder reflection leaves the two-dimensional subspace + * spanned by the first two unit vectors invariant, and so on up to the last reflection which leaves all but + * one dimensions invariant and acts only on the last dimension. Such sequences of Householder reflections + * are used in several algorithms to zero out certain parts of a matrix. Indeed, the methods + * HessenbergDecomposition::matrixQ(), Tridiagonalization::matrixQ(), HouseholderQR::householderQ(), + * and ColPivHouseholderQR::householderQ() all return a %HouseholderSequence. + * + * More precisely, the class %HouseholderSequence represents an \f$ n \times n \f$ matrix \f$ H \f$ of the + * form \f$ H = \prod_{i=0}^{n-1} H_i \f$ where the i-th Householder reflection is \f$ H_i = I - h_i v_i + * v_i^* \f$. The i-th Householder coefficient \f$ h_i \f$ is a scalar and the i-th Householder vector \f$ + * v_i \f$ is a vector of the form + * \f[ + * v_i = [\underbrace{0, \ldots, 0}_{i-1\mbox{ zeros}}, 1, \underbrace{*, \ldots,*}_{n-i\mbox{ arbitrary entries}} ]. + * \f] + * The last \f$ n-i \f$ entries of \f$ v_i \f$ are called the essential part of the Householder vector. + * + * Typical usages are listed below, where H is a HouseholderSequence: + * \code + * A.applyOnTheRight(H); // A = A * H + * A.applyOnTheLeft(H); // A = H * A + * A.applyOnTheRight(H.adjoint()); // A = A * H^* + * A.applyOnTheLeft(H.adjoint()); // A = H^* * A + * MatrixXd Q = H; // conversion to a dense matrix + * \endcode + * In addition to the adjoint, you can also apply the inverse (=adjoint), the transpose, and the conjugate operators. + * + * See the documentation for HouseholderSequence(const VectorsType&, const CoeffsType&) for an example. + * + * \sa MatrixBase::applyOnTheLeft(), MatrixBase::applyOnTheRight() + */ + +namespace internal { + +template<typename VectorsType, typename CoeffsType, int Side> +struct traits<HouseholderSequence<VectorsType,CoeffsType,Side> > +{ + typedef typename VectorsType::Scalar Scalar; + typedef typename VectorsType::Index Index; + typedef typename VectorsType::StorageKind StorageKind; + enum { + RowsAtCompileTime = Side==OnTheLeft ? traits<VectorsType>::RowsAtCompileTime + : traits<VectorsType>::ColsAtCompileTime, + ColsAtCompileTime = RowsAtCompileTime, + MaxRowsAtCompileTime = Side==OnTheLeft ? traits<VectorsType>::MaxRowsAtCompileTime + : traits<VectorsType>::MaxColsAtCompileTime, + MaxColsAtCompileTime = MaxRowsAtCompileTime, + Flags = 0 + }; +}; + +template<typename VectorsType, typename CoeffsType, int Side> +struct hseq_side_dependent_impl +{ + typedef Block<const VectorsType, Dynamic, 1> EssentialVectorType; + typedef HouseholderSequence<VectorsType, CoeffsType, OnTheLeft> HouseholderSequenceType; + typedef typename VectorsType::Index Index; + static inline const EssentialVectorType essentialVector(const HouseholderSequenceType& h, Index k) + { + Index start = k+1+h.m_shift; + return Block<const VectorsType,Dynamic,1>(h.m_vectors, start, k, h.rows()-start, 1); + } +}; + +template<typename VectorsType, typename CoeffsType> +struct hseq_side_dependent_impl<VectorsType, CoeffsType, OnTheRight> +{ + typedef Transpose<Block<const VectorsType, 1, Dynamic> > EssentialVectorType; + typedef HouseholderSequence<VectorsType, CoeffsType, OnTheRight> HouseholderSequenceType; + typedef typename VectorsType::Index Index; + static inline const EssentialVectorType essentialVector(const HouseholderSequenceType& h, Index k) + { + Index start = k+1+h.m_shift; + return Block<const VectorsType,1,Dynamic>(h.m_vectors, k, start, 1, h.rows()-start).transpose(); + } +}; + +template<typename OtherScalarType, typename MatrixType> struct matrix_type_times_scalar_type +{ + typedef typename scalar_product_traits<OtherScalarType, typename MatrixType::Scalar>::ReturnType + ResultScalar; + typedef Matrix<ResultScalar, MatrixType::RowsAtCompileTime, MatrixType::ColsAtCompileTime, + 0, MatrixType::MaxRowsAtCompileTime, MatrixType::MaxColsAtCompileTime> Type; +}; + +} // end namespace internal + +template<typename VectorsType, typename CoeffsType, int Side> class HouseholderSequence + : public EigenBase<HouseholderSequence<VectorsType,CoeffsType,Side> > +{ + typedef typename internal::hseq_side_dependent_impl<VectorsType,CoeffsType,Side>::EssentialVectorType EssentialVectorType; + + public: + enum { + RowsAtCompileTime = internal::traits<HouseholderSequence>::RowsAtCompileTime, + ColsAtCompileTime = internal::traits<HouseholderSequence>::ColsAtCompileTime, + MaxRowsAtCompileTime = internal::traits<HouseholderSequence>::MaxRowsAtCompileTime, + MaxColsAtCompileTime = internal::traits<HouseholderSequence>::MaxColsAtCompileTime + }; + typedef typename internal::traits<HouseholderSequence>::Scalar Scalar; + typedef typename VectorsType::Index Index; + + typedef HouseholderSequence< + typename internal::conditional<NumTraits<Scalar>::IsComplex, + typename internal::remove_all<typename VectorsType::ConjugateReturnType>::type, + VectorsType>::type, + typename internal::conditional<NumTraits<Scalar>::IsComplex, + typename internal::remove_all<typename CoeffsType::ConjugateReturnType>::type, + CoeffsType>::type, + Side + > ConjugateReturnType; + + /** \brief Constructor. + * \param[in] v %Matrix containing the essential parts of the Householder vectors + * \param[in] h Vector containing the Householder coefficients + * + * Constructs the Householder sequence with coefficients given by \p h and vectors given by \p v. The + * i-th Householder coefficient \f$ h_i \f$ is given by \p h(i) and the essential part of the i-th + * Householder vector \f$ v_i \f$ is given by \p v(k,i) with \p k > \p i (the subdiagonal part of the + * i-th column). If \p v has fewer columns than rows, then the Householder sequence contains as many + * Householder reflections as there are columns. + * + * \note The %HouseholderSequence object stores \p v and \p h by reference. + * + * Example: \include HouseholderSequence_HouseholderSequence.cpp + * Output: \verbinclude HouseholderSequence_HouseholderSequence.out + * + * \sa setLength(), setShift() + */ + HouseholderSequence(const VectorsType& v, const CoeffsType& h) + : m_vectors(v), m_coeffs(h), m_trans(false), m_length(v.diagonalSize()), + m_shift(0) + { + } + + /** \brief Copy constructor. */ + HouseholderSequence(const HouseholderSequence& other) + : m_vectors(other.m_vectors), + m_coeffs(other.m_coeffs), + m_trans(other.m_trans), + m_length(other.m_length), + m_shift(other.m_shift) + { + } + + /** \brief Number of rows of transformation viewed as a matrix. + * \returns Number of rows + * \details This equals the dimension of the space that the transformation acts on. + */ + Index rows() const { return Side==OnTheLeft ? m_vectors.rows() : m_vectors.cols(); } + + /** \brief Number of columns of transformation viewed as a matrix. + * \returns Number of columns + * \details This equals the dimension of the space that the transformation acts on. + */ + Index cols() const { return rows(); } + + /** \brief Essential part of a Householder vector. + * \param[in] k Index of Householder reflection + * \returns Vector containing non-trivial entries of k-th Householder vector + * + * This function returns the essential part of the Householder vector \f$ v_i \f$. This is a vector of + * length \f$ n-i \f$ containing the last \f$ n-i \f$ entries of the vector + * \f[ + * v_i = [\underbrace{0, \ldots, 0}_{i-1\mbox{ zeros}}, 1, \underbrace{*, \ldots,*}_{n-i\mbox{ arbitrary entries}} ]. + * \f] + * The index \f$ i \f$ equals \p k + shift(), corresponding to the k-th column of the matrix \p v + * passed to the constructor. + * + * \sa setShift(), shift() + */ + const EssentialVectorType essentialVector(Index k) const + { + eigen_assert(k >= 0 && k < m_length); + return internal::hseq_side_dependent_impl<VectorsType,CoeffsType,Side>::essentialVector(*this, k); + } + + /** \brief %Transpose of the Householder sequence. */ + HouseholderSequence transpose() const + { + return HouseholderSequence(*this).setTrans(!m_trans); + } + + /** \brief Complex conjugate of the Householder sequence. */ + ConjugateReturnType conjugate() const + { + return ConjugateReturnType(m_vectors.conjugate(), m_coeffs.conjugate()) + .setTrans(m_trans) + .setLength(m_length) + .setShift(m_shift); + } + + /** \brief Adjoint (conjugate transpose) of the Householder sequence. */ + ConjugateReturnType adjoint() const + { + return conjugate().setTrans(!m_trans); + } + + /** \brief Inverse of the Householder sequence (equals the adjoint). */ + ConjugateReturnType inverse() const { return adjoint(); } + + /** \internal */ + template<typename DestType> inline void evalTo(DestType& dst) const + { + Matrix<Scalar, DestType::RowsAtCompileTime, 1, + AutoAlign|ColMajor, DestType::MaxRowsAtCompileTime, 1> workspace(rows()); + evalTo(dst, workspace); + } + + /** \internal */ + template<typename Dest, typename Workspace> + void evalTo(Dest& dst, Workspace& workspace) const + { + workspace.resize(rows()); + Index vecs = m_length; + if( internal::is_same<typename internal::remove_all<VectorsType>::type,Dest>::value + && internal::extract_data(dst) == internal::extract_data(m_vectors)) + { + // in-place + dst.diagonal().setOnes(); + dst.template triangularView<StrictlyUpper>().setZero(); + for(Index k = vecs-1; k >= 0; --k) + { + Index cornerSize = rows() - k - m_shift; + if(m_trans) + dst.bottomRightCorner(cornerSize, cornerSize) + .applyHouseholderOnTheRight(essentialVector(k), m_coeffs.coeff(k), workspace.data()); + else + dst.bottomRightCorner(cornerSize, cornerSize) + .applyHouseholderOnTheLeft(essentialVector(k), m_coeffs.coeff(k), workspace.data()); + + // clear the off diagonal vector + dst.col(k).tail(rows()-k-1).setZero(); + } + // clear the remaining columns if needed + for(Index k = 0; k<cols()-vecs ; ++k) + dst.col(k).tail(rows()-k-1).setZero(); + } + else + { + dst.setIdentity(rows(), rows()); + for(Index k = vecs-1; k >= 0; --k) + { + Index cornerSize = rows() - k - m_shift; + if(m_trans) + dst.bottomRightCorner(cornerSize, cornerSize) + .applyHouseholderOnTheRight(essentialVector(k), m_coeffs.coeff(k), &workspace.coeffRef(0)); + else + dst.bottomRightCorner(cornerSize, cornerSize) + .applyHouseholderOnTheLeft(essentialVector(k), m_coeffs.coeff(k), &workspace.coeffRef(0)); + } + } + } + + /** \internal */ + template<typename Dest> inline void applyThisOnTheRight(Dest& dst) const + { + Matrix<Scalar,1,Dest::RowsAtCompileTime,RowMajor,1,Dest::MaxRowsAtCompileTime> workspace(dst.rows()); + applyThisOnTheRight(dst, workspace); + } + + /** \internal */ + template<typename Dest, typename Workspace> + inline void applyThisOnTheRight(Dest& dst, Workspace& workspace) const + { + workspace.resize(dst.rows()); + for(Index k = 0; k < m_length; ++k) + { + Index actual_k = m_trans ? m_length-k-1 : k; + dst.rightCols(rows()-m_shift-actual_k) + .applyHouseholderOnTheRight(essentialVector(actual_k), m_coeffs.coeff(actual_k), workspace.data()); + } + } + + /** \internal */ + template<typename Dest> inline void applyThisOnTheLeft(Dest& dst) const + { + Matrix<Scalar,1,Dest::ColsAtCompileTime,RowMajor,1,Dest::MaxColsAtCompileTime> workspace(dst.cols()); + applyThisOnTheLeft(dst, workspace); + } + + /** \internal */ + template<typename Dest, typename Workspace> + inline void applyThisOnTheLeft(Dest& dst, Workspace& workspace) const + { + workspace.resize(dst.cols()); + for(Index k = 0; k < m_length; ++k) + { + Index actual_k = m_trans ? k : m_length-k-1; + dst.bottomRows(rows()-m_shift-actual_k) + .applyHouseholderOnTheLeft(essentialVector(actual_k), m_coeffs.coeff(actual_k), workspace.data()); + } + } + + /** \brief Computes the product of a Householder sequence with a matrix. + * \param[in] other %Matrix being multiplied. + * \returns Expression object representing the product. + * + * This function computes \f$ HM \f$ where \f$ H \f$ is the Householder sequence represented by \p *this + * and \f$ M \f$ is the matrix \p other. + */ + template<typename OtherDerived> + typename internal::matrix_type_times_scalar_type<Scalar, OtherDerived>::Type operator*(const MatrixBase<OtherDerived>& other) const + { + typename internal::matrix_type_times_scalar_type<Scalar, OtherDerived>::Type + res(other.template cast<typename internal::matrix_type_times_scalar_type<Scalar,OtherDerived>::ResultScalar>()); + applyThisOnTheLeft(res); + return res; + } + + template<typename _VectorsType, typename _CoeffsType, int _Side> friend struct internal::hseq_side_dependent_impl; + + /** \brief Sets the length of the Householder sequence. + * \param [in] length New value for the length. + * + * By default, the length \f$ n \f$ of the Householder sequence \f$ H = H_0 H_1 \ldots H_{n-1} \f$ is set + * to the number of columns of the matrix \p v passed to the constructor, or the number of rows if that + * is smaller. After this function is called, the length equals \p length. + * + * \sa length() + */ + HouseholderSequence& setLength(Index length) + { + m_length = length; + return *this; + } + + /** \brief Sets the shift of the Householder sequence. + * \param [in] shift New value for the shift. + * + * By default, a %HouseholderSequence object represents \f$ H = H_0 H_1 \ldots H_{n-1} \f$ and the i-th + * column of the matrix \p v passed to the constructor corresponds to the i-th Householder + * reflection. After this function is called, the object represents \f$ H = H_{\mathrm{shift}} + * H_{\mathrm{shift}+1} \ldots H_{n-1} \f$ and the i-th column of \p v corresponds to the (shift+i)-th + * Householder reflection. + * + * \sa shift() + */ + HouseholderSequence& setShift(Index shift) + { + m_shift = shift; + return *this; + } + + Index length() const { return m_length; } /**< \brief Returns the length of the Householder sequence. */ + Index shift() const { return m_shift; } /**< \brief Returns the shift of the Householder sequence. */ + + /* Necessary for .adjoint() and .conjugate() */ + template <typename VectorsType2, typename CoeffsType2, int Side2> friend class HouseholderSequence; + + protected: + + /** \brief Sets the transpose flag. + * \param [in] trans New value of the transpose flag. + * + * By default, the transpose flag is not set. If the transpose flag is set, then this object represents + * \f$ H^T = H_{n-1}^T \ldots H_1^T H_0^T \f$ instead of \f$ H = H_0 H_1 \ldots H_{n-1} \f$. + * + * \sa trans() + */ + HouseholderSequence& setTrans(bool trans) + { + m_trans = trans; + return *this; + } + + bool trans() const { return m_trans; } /**< \brief Returns the transpose flag. */ + + typename VectorsType::Nested m_vectors; + typename CoeffsType::Nested m_coeffs; + bool m_trans; + Index m_length; + Index m_shift; +}; + +/** \brief Computes the product of a matrix with a Householder sequence. + * \param[in] other %Matrix being multiplied. + * \param[in] h %HouseholderSequence being multiplied. + * \returns Expression object representing the product. + * + * This function computes \f$ MH \f$ where \f$ M \f$ is the matrix \p other and \f$ H \f$ is the + * Householder sequence represented by \p h. + */ +template<typename OtherDerived, typename VectorsType, typename CoeffsType, int Side> +typename internal::matrix_type_times_scalar_type<typename VectorsType::Scalar,OtherDerived>::Type operator*(const MatrixBase<OtherDerived>& other, const HouseholderSequence<VectorsType,CoeffsType,Side>& h) +{ + typename internal::matrix_type_times_scalar_type<typename VectorsType::Scalar,OtherDerived>::Type + res(other.template cast<typename internal::matrix_type_times_scalar_type<typename VectorsType::Scalar,OtherDerived>::ResultScalar>()); + h.applyThisOnTheRight(res); + return res; +} + +/** \ingroup Householder_Module \householder_module + * \brief Convenience function for constructing a Householder sequence. + * \returns A HouseholderSequence constructed from the specified arguments. + */ +template<typename VectorsType, typename CoeffsType> +HouseholderSequence<VectorsType,CoeffsType> householderSequence(const VectorsType& v, const CoeffsType& h) +{ + return HouseholderSequence<VectorsType,CoeffsType,OnTheLeft>(v, h); +} + +/** \ingroup Householder_Module \householder_module + * \brief Convenience function for constructing a Householder sequence. + * \returns A HouseholderSequence constructed from the specified arguments. + * \details This function differs from householderSequence() in that the template argument \p OnTheSide of + * the constructed HouseholderSequence is set to OnTheRight, instead of the default OnTheLeft. + */ +template<typename VectorsType, typename CoeffsType> +HouseholderSequence<VectorsType,CoeffsType,OnTheRight> rightHouseholderSequence(const VectorsType& v, const CoeffsType& h) +{ + return HouseholderSequence<VectorsType,CoeffsType,OnTheRight>(v, h); +} + +} // end namespace Eigen + +#endif // EIGEN_HOUSEHOLDER_SEQUENCE_H |