| // This file is part of Eigen, a lightweight C++ template library |
| // for linear algebra. |
| // |
| // Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr> |
| // Copyright (C) 2009 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_COLPIVOTINGHOUSEHOLDERQR_H |
| #define EIGEN_COLPIVOTINGHOUSEHOLDERQR_H |
| |
| namespace Eigen { |
| |
| namespace internal { |
| template<typename _MatrixType> struct traits<ColPivHouseholderQR<_MatrixType> > |
| : traits<_MatrixType> |
| { |
| enum { Flags = 0 }; |
| }; |
| |
| } // end namespace internal |
| |
| /** \ingroup QR_Module |
| * |
| * \class ColPivHouseholderQR |
| * |
| * \brief Householder rank-revealing QR decomposition of a matrix with column-pivoting |
| * |
| * \tparam _MatrixType the type of the matrix of which we are computing the QR decomposition |
| * |
| * This class performs a rank-revealing QR decomposition of a matrix \b A into matrices \b P, \b Q and \b R |
| * such that |
| * \f[ |
| * \mathbf{A} \, \mathbf{P} = \mathbf{Q} \, \mathbf{R} |
| * \f] |
| * by using Householder transformations. Here, \b P is a permutation matrix, \b Q a unitary matrix and \b R an |
| * upper triangular matrix. |
| * |
| * This decomposition performs column pivoting in order to be rank-revealing and improve |
| * numerical stability. It is slower than HouseholderQR, and faster than FullPivHouseholderQR. |
| * |
| * This class supports the \link InplaceDecomposition inplace decomposition \endlink mechanism. |
| * |
| * \sa MatrixBase::colPivHouseholderQr() |
| */ |
| template<typename _MatrixType> class ColPivHouseholderQR |
| { |
| public: |
| |
| typedef _MatrixType MatrixType; |
| enum { |
| RowsAtCompileTime = MatrixType::RowsAtCompileTime, |
| ColsAtCompileTime = MatrixType::ColsAtCompileTime, |
| MaxRowsAtCompileTime = MatrixType::MaxRowsAtCompileTime, |
| MaxColsAtCompileTime = MatrixType::MaxColsAtCompileTime |
| }; |
| typedef typename MatrixType::Scalar Scalar; |
| typedef typename MatrixType::RealScalar RealScalar; |
| // FIXME should be int |
| typedef typename MatrixType::StorageIndex StorageIndex; |
| typedef typename internal::plain_diag_type<MatrixType>::type HCoeffsType; |
| typedef PermutationMatrix<ColsAtCompileTime, MaxColsAtCompileTime> PermutationType; |
| typedef typename internal::plain_row_type<MatrixType, Index>::type IntRowVectorType; |
| typedef typename internal::plain_row_type<MatrixType>::type RowVectorType; |
| typedef typename internal::plain_row_type<MatrixType, RealScalar>::type RealRowVectorType; |
| typedef HouseholderSequence<MatrixType,typename internal::remove_all<typename HCoeffsType::ConjugateReturnType>::type> HouseholderSequenceType; |
| typedef typename MatrixType::PlainObject PlainObject; |
| |
| private: |
| |
| typedef typename PermutationType::StorageIndex PermIndexType; |
| |
| public: |
| |
| /** |
| * \brief Default Constructor. |
| * |
| * The default constructor is useful in cases in which the user intends to |
| * perform decompositions via ColPivHouseholderQR::compute(const MatrixType&). |
| */ |
| ColPivHouseholderQR() |
| : m_qr(), |
| m_hCoeffs(), |
| m_colsPermutation(), |
| m_colsTranspositions(), |
| m_temp(), |
| m_colNormsUpdated(), |
| m_colNormsDirect(), |
| m_isInitialized(false), |
| m_usePrescribedThreshold(false) {} |
| |
| /** \brief Default Constructor with memory preallocation |
| * |
| * Like the default constructor but with preallocation of the internal data |
| * according to the specified problem \a size. |
| * \sa ColPivHouseholderQR() |
| */ |
| ColPivHouseholderQR(Index rows, Index cols) |
| : m_qr(rows, cols), |
| m_hCoeffs((std::min)(rows,cols)), |
| m_colsPermutation(PermIndexType(cols)), |
| m_colsTranspositions(cols), |
| m_temp(cols), |
| m_colNormsUpdated(cols), |
| m_colNormsDirect(cols), |
| m_isInitialized(false), |
| m_usePrescribedThreshold(false) {} |
| |
| /** \brief Constructs a QR factorization from a given matrix |
| * |
| * This constructor computes the QR factorization of the matrix \a matrix by calling |
| * the method compute(). It is a short cut for: |
| * |
| * \code |
| * ColPivHouseholderQR<MatrixType> qr(matrix.rows(), matrix.cols()); |
| * qr.compute(matrix); |
| * \endcode |
| * |
| * \sa compute() |
| */ |
| template<typename InputType> |
| explicit ColPivHouseholderQR(const EigenBase<InputType>& matrix) |
| : m_qr(matrix.rows(), matrix.cols()), |
| m_hCoeffs((std::min)(matrix.rows(),matrix.cols())), |
| m_colsPermutation(PermIndexType(matrix.cols())), |
| m_colsTranspositions(matrix.cols()), |
| m_temp(matrix.cols()), |
| m_colNormsUpdated(matrix.cols()), |
| m_colNormsDirect(matrix.cols()), |
| m_isInitialized(false), |
| m_usePrescribedThreshold(false) |
| { |
| compute(matrix.derived()); |
| } |
| |
| /** \brief Constructs a QR factorization from a given matrix |
| * |
| * This overloaded constructor is provided for \link InplaceDecomposition inplace decomposition \endlink when \c MatrixType is a Eigen::Ref. |
| * |
| * \sa ColPivHouseholderQR(const EigenBase&) |
| */ |
| template<typename InputType> |
| explicit ColPivHouseholderQR(EigenBase<InputType>& matrix) |
| : m_qr(matrix.derived()), |
| m_hCoeffs((std::min)(matrix.rows(),matrix.cols())), |
| m_colsPermutation(PermIndexType(matrix.cols())), |
| m_colsTranspositions(matrix.cols()), |
| m_temp(matrix.cols()), |
| m_colNormsUpdated(matrix.cols()), |
| m_colNormsDirect(matrix.cols()), |
| m_isInitialized(false), |
| m_usePrescribedThreshold(false) |
| { |
| computeInPlace(); |
| } |
| |
| /** This method finds a solution x to the equation Ax=b, where A is the matrix of which |
| * *this is the QR decomposition, if any exists. |
| * |
| * \param b the right-hand-side of the equation to solve. |
| * |
| * \returns a solution. |
| * |
| * \note_about_checking_solutions |
| * |
| * \note_about_arbitrary_choice_of_solution |
| * |
| * Example: \include ColPivHouseholderQR_solve.cpp |
| * Output: \verbinclude ColPivHouseholderQR_solve.out |
| */ |
| template<typename Rhs> |
| inline const Solve<ColPivHouseholderQR, Rhs> |
| solve(const MatrixBase<Rhs>& b) const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return Solve<ColPivHouseholderQR, Rhs>(*this, b.derived()); |
| } |
| |
| HouseholderSequenceType householderQ() const; |
| HouseholderSequenceType matrixQ() const |
| { |
| return householderQ(); |
| } |
| |
| /** \returns a reference to the matrix where the Householder QR decomposition is stored |
| */ |
| const MatrixType& matrixQR() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return m_qr; |
| } |
| |
| /** \returns a reference to the matrix where the result Householder QR is stored |
| * \warning The strict lower part of this matrix contains internal values. |
| * Only the upper triangular part should be referenced. To get it, use |
| * \code matrixR().template triangularView<Upper>() \endcode |
| * For rank-deficient matrices, use |
| * \code |
| * matrixR().topLeftCorner(rank(), rank()).template triangularView<Upper>() |
| * \endcode |
| */ |
| const MatrixType& matrixR() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return m_qr; |
| } |
| |
| template<typename InputType> |
| ColPivHouseholderQR& compute(const EigenBase<InputType>& matrix); |
| |
| /** \returns a const reference to the column permutation matrix */ |
| const PermutationType& colsPermutation() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return m_colsPermutation; |
| } |
| |
| /** \returns the absolute value of the determinant of the matrix of which |
| * *this is the QR decomposition. It has only linear complexity |
| * (that is, O(n) where n is the dimension of the square matrix) |
| * as the QR decomposition has already been computed. |
| * |
| * \note This is only for square matrices. |
| * |
| * \warning a determinant can be very big or small, so for matrices |
| * of large enough dimension, there is a risk of overflow/underflow. |
| * One way to work around that is to use logAbsDeterminant() instead. |
| * |
| * \sa logAbsDeterminant(), MatrixBase::determinant() |
| */ |
| typename MatrixType::RealScalar absDeterminant() const; |
| |
| /** \returns the natural log of the absolute value of the determinant of the matrix of which |
| * *this is the QR decomposition. It has only linear complexity |
| * (that is, O(n) where n is the dimension of the square matrix) |
| * as the QR decomposition has already been computed. |
| * |
| * \note This is only for square matrices. |
| * |
| * \note This method is useful to work around the risk of overflow/underflow that's inherent |
| * to determinant computation. |
| * |
| * \sa absDeterminant(), MatrixBase::determinant() |
| */ |
| typename MatrixType::RealScalar logAbsDeterminant() const; |
| |
| /** \returns the rank of the matrix of which *this is the QR decomposition. |
| * |
| * \note This method has to determine which pivots should be considered nonzero. |
| * For that, it uses the threshold value that you can control by calling |
| * setThreshold(const RealScalar&). |
| */ |
| inline Index rank() const |
| { |
| using std::abs; |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| RealScalar premultiplied_threshold = abs(m_maxpivot) * threshold(); |
| Index result = 0; |
| for(Index i = 0; i < m_nonzero_pivots; ++i) |
| result += (abs(m_qr.coeff(i,i)) > premultiplied_threshold); |
| return result; |
| } |
| |
| /** \returns the dimension of the kernel of the matrix of which *this is the QR decomposition. |
| * |
| * \note This method has to determine which pivots should be considered nonzero. |
| * For that, it uses the threshold value that you can control by calling |
| * setThreshold(const RealScalar&). |
| */ |
| inline Index dimensionOfKernel() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return cols() - rank(); |
| } |
| |
| /** \returns true if the matrix of which *this is the QR decomposition represents an injective |
| * linear map, i.e. has trivial kernel; false otherwise. |
| * |
| * \note This method has to determine which pivots should be considered nonzero. |
| * For that, it uses the threshold value that you can control by calling |
| * setThreshold(const RealScalar&). |
| */ |
| inline bool isInjective() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return rank() == cols(); |
| } |
| |
| /** \returns true if the matrix of which *this is the QR decomposition represents a surjective |
| * linear map; false otherwise. |
| * |
| * \note This method has to determine which pivots should be considered nonzero. |
| * For that, it uses the threshold value that you can control by calling |
| * setThreshold(const RealScalar&). |
| */ |
| inline bool isSurjective() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return rank() == rows(); |
| } |
| |
| /** \returns true if the matrix of which *this is the QR decomposition is invertible. |
| * |
| * \note This method has to determine which pivots should be considered nonzero. |
| * For that, it uses the threshold value that you can control by calling |
| * setThreshold(const RealScalar&). |
| */ |
| inline bool isInvertible() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return isInjective() && isSurjective(); |
| } |
| |
| /** \returns the inverse of the matrix of which *this is the QR decomposition. |
| * |
| * \note If this matrix is not invertible, the returned matrix has undefined coefficients. |
| * Use isInvertible() to first determine whether this matrix is invertible. |
| */ |
| inline const Inverse<ColPivHouseholderQR> inverse() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return Inverse<ColPivHouseholderQR>(*this); |
| } |
| |
| inline Index rows() const { return m_qr.rows(); } |
| inline Index cols() const { return m_qr.cols(); } |
| |
| /** \returns a const reference to the vector of Householder coefficients used to represent the factor \c Q. |
| * |
| * For advanced uses only. |
| */ |
| const HCoeffsType& hCoeffs() const { return m_hCoeffs; } |
| |
| /** Allows to prescribe a threshold to be used by certain methods, such as rank(), |
| * who need to determine when pivots are to be considered nonzero. This is not used for the |
| * QR decomposition itself. |
| * |
| * When it needs to get the threshold value, Eigen calls threshold(). By default, this |
| * uses a formula to automatically determine a reasonable threshold. |
| * Once you have called the present method setThreshold(const RealScalar&), |
| * your value is used instead. |
| * |
| * \param threshold The new value to use as the threshold. |
| * |
| * A pivot will be considered nonzero if its absolute value is strictly greater than |
| * \f$ \vert pivot \vert \leqslant threshold \times \vert maxpivot \vert \f$ |
| * where maxpivot is the biggest pivot. |
| * |
| * If you want to come back to the default behavior, call setThreshold(Default_t) |
| */ |
| ColPivHouseholderQR& setThreshold(const RealScalar& threshold) |
| { |
| m_usePrescribedThreshold = true; |
| m_prescribedThreshold = threshold; |
| return *this; |
| } |
| |
| /** Allows to come back to the default behavior, letting Eigen use its default formula for |
| * determining the threshold. |
| * |
| * You should pass the special object Eigen::Default as parameter here. |
| * \code qr.setThreshold(Eigen::Default); \endcode |
| * |
| * See the documentation of setThreshold(const RealScalar&). |
| */ |
| ColPivHouseholderQR& setThreshold(Default_t) |
| { |
| m_usePrescribedThreshold = false; |
| return *this; |
| } |
| |
| /** Returns the threshold that will be used by certain methods such as rank(). |
| * |
| * See the documentation of setThreshold(const RealScalar&). |
| */ |
| RealScalar threshold() const |
| { |
| eigen_assert(m_isInitialized || m_usePrescribedThreshold); |
| return m_usePrescribedThreshold ? m_prescribedThreshold |
| // this formula comes from experimenting (see "LU precision tuning" thread on the list) |
| // and turns out to be identical to Higham's formula used already in LDLt. |
| : NumTraits<Scalar>::epsilon() * RealScalar(m_qr.diagonalSize()); |
| } |
| |
| /** \returns the number of nonzero pivots in the QR decomposition. |
| * Here nonzero is meant in the exact sense, not in a fuzzy sense. |
| * So that notion isn't really intrinsically interesting, but it is |
| * still useful when implementing algorithms. |
| * |
| * \sa rank() |
| */ |
| inline Index nonzeroPivots() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return m_nonzero_pivots; |
| } |
| |
| /** \returns the absolute value of the biggest pivot, i.e. the biggest |
| * diagonal coefficient of R. |
| */ |
| RealScalar maxPivot() const { return m_maxpivot; } |
| |
| /** \brief Reports whether the QR factorization was succesful. |
| * |
| * \note This function always returns \c Success. It is provided for compatibility |
| * with other factorization routines. |
| * \returns \c Success |
| */ |
| ComputationInfo info() const |
| { |
| eigen_assert(m_isInitialized && "Decomposition is not initialized."); |
| return Success; |
| } |
| |
| #ifndef EIGEN_PARSED_BY_DOXYGEN |
| template<typename RhsType, typename DstType> |
| EIGEN_DEVICE_FUNC |
| void _solve_impl(const RhsType &rhs, DstType &dst) const; |
| #endif |
| |
| protected: |
| |
| friend class CompleteOrthogonalDecomposition<MatrixType>; |
| |
| static void check_template_parameters() |
| { |
| EIGEN_STATIC_ASSERT_NON_INTEGER(Scalar); |
| } |
| |
| void computeInPlace(); |
| |
| MatrixType m_qr; |
| HCoeffsType m_hCoeffs; |
| PermutationType m_colsPermutation; |
| IntRowVectorType m_colsTranspositions; |
| RowVectorType m_temp; |
| RealRowVectorType m_colNormsUpdated; |
| RealRowVectorType m_colNormsDirect; |
| bool m_isInitialized, m_usePrescribedThreshold; |
| RealScalar m_prescribedThreshold, m_maxpivot; |
| Index m_nonzero_pivots; |
| Index m_det_pq; |
| }; |
| |
| template<typename MatrixType> |
| typename MatrixType::RealScalar ColPivHouseholderQR<MatrixType>::absDeterminant() const |
| { |
| using std::abs; |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| eigen_assert(m_qr.rows() == m_qr.cols() && "You can't take the determinant of a non-square matrix!"); |
| return abs(m_qr.diagonal().prod()); |
| } |
| |
| template<typename MatrixType> |
| typename MatrixType::RealScalar ColPivHouseholderQR<MatrixType>::logAbsDeterminant() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| eigen_assert(m_qr.rows() == m_qr.cols() && "You can't take the determinant of a non-square matrix!"); |
| return m_qr.diagonal().cwiseAbs().array().log().sum(); |
| } |
| |
| /** Performs the QR factorization of the given matrix \a matrix. The result of |
| * the factorization is stored into \c *this, and a reference to \c *this |
| * is returned. |
| * |
| * \sa class ColPivHouseholderQR, ColPivHouseholderQR(const MatrixType&) |
| */ |
| template<typename MatrixType> |
| template<typename InputType> |
| ColPivHouseholderQR<MatrixType>& ColPivHouseholderQR<MatrixType>::compute(const EigenBase<InputType>& matrix) |
| { |
| m_qr = matrix.derived(); |
| computeInPlace(); |
| return *this; |
| } |
| |
| template<typename MatrixType> |
| void ColPivHouseholderQR<MatrixType>::computeInPlace() |
| { |
| check_template_parameters(); |
| |
| // the column permutation is stored as int indices, so just to be sure: |
| eigen_assert(m_qr.cols()<=NumTraits<int>::highest()); |
| |
| using std::abs; |
| |
| Index rows = m_qr.rows(); |
| Index cols = m_qr.cols(); |
| Index size = m_qr.diagonalSize(); |
| |
| m_hCoeffs.resize(size); |
| |
| m_temp.resize(cols); |
| |
| m_colsTranspositions.resize(m_qr.cols()); |
| Index number_of_transpositions = 0; |
| |
| m_colNormsUpdated.resize(cols); |
| m_colNormsDirect.resize(cols); |
| for (Index k = 0; k < cols; ++k) { |
| // colNormsDirect(k) caches the most recent directly computed norm of |
| // column k. |
| m_colNormsDirect.coeffRef(k) = m_qr.col(k).norm(); |
| m_colNormsUpdated.coeffRef(k) = m_colNormsDirect.coeffRef(k); |
| } |
| |
| RealScalar threshold_helper = numext::abs2<RealScalar>(m_colNormsUpdated.maxCoeff() * NumTraits<RealScalar>::epsilon()) / RealScalar(rows); |
| RealScalar norm_downdate_threshold = numext::sqrt(NumTraits<RealScalar>::epsilon()); |
| |
| m_nonzero_pivots = size; // the generic case is that in which all pivots are nonzero (invertible case) |
| m_maxpivot = RealScalar(0); |
| |
| for(Index k = 0; k < size; ++k) |
| { |
| // first, we look up in our table m_colNormsUpdated which column has the biggest norm |
| Index biggest_col_index; |
| RealScalar biggest_col_sq_norm = numext::abs2(m_colNormsUpdated.tail(cols-k).maxCoeff(&biggest_col_index)); |
| biggest_col_index += k; |
| |
| // Track the number of meaningful pivots but do not stop the decomposition to make |
| // sure that the initial matrix is properly reproduced. See bug 941. |
| if(m_nonzero_pivots==size && biggest_col_sq_norm < threshold_helper * RealScalar(rows-k)) |
| m_nonzero_pivots = k; |
| |
| // apply the transposition to the columns |
| m_colsTranspositions.coeffRef(k) = biggest_col_index; |
| if(k != biggest_col_index) { |
| m_qr.col(k).swap(m_qr.col(biggest_col_index)); |
| std::swap(m_colNormsUpdated.coeffRef(k), m_colNormsUpdated.coeffRef(biggest_col_index)); |
| std::swap(m_colNormsDirect.coeffRef(k), m_colNormsDirect.coeffRef(biggest_col_index)); |
| ++number_of_transpositions; |
| } |
| |
| // generate the householder vector, store it below the diagonal |
| RealScalar beta; |
| m_qr.col(k).tail(rows-k).makeHouseholderInPlace(m_hCoeffs.coeffRef(k), beta); |
| |
| // apply the householder transformation to the diagonal coefficient |
| m_qr.coeffRef(k,k) = beta; |
| |
| // remember the maximum absolute value of diagonal coefficients |
| if(abs(beta) > m_maxpivot) m_maxpivot = abs(beta); |
| |
| // apply the householder transformation |
| m_qr.bottomRightCorner(rows-k, cols-k-1) |
| .applyHouseholderOnTheLeft(m_qr.col(k).tail(rows-k-1), m_hCoeffs.coeffRef(k), &m_temp.coeffRef(k+1)); |
| |
| // update our table of norms of the columns |
| for (Index j = k + 1; j < cols; ++j) { |
| // The following implements the stable norm downgrade step discussed in |
| // http://www.netlib.org/lapack/lawnspdf/lawn176.pdf |
| // and used in LAPACK routines xGEQPF and xGEQP3. |
| // See lines 278-297 in http://www.netlib.org/lapack/explore-html/dc/df4/sgeqpf_8f_source.html |
| if (m_colNormsUpdated.coeffRef(j) != RealScalar(0)) { |
| RealScalar temp = abs(m_qr.coeffRef(k, j)) / m_colNormsUpdated.coeffRef(j); |
| temp = (RealScalar(1) + temp) * (RealScalar(1) - temp); |
| temp = temp < RealScalar(0) ? RealScalar(0) : temp; |
| RealScalar temp2 = temp * numext::abs2<RealScalar>(m_colNormsUpdated.coeffRef(j) / |
| m_colNormsDirect.coeffRef(j)); |
| if (temp2 <= norm_downdate_threshold) { |
| // The updated norm has become too inaccurate so re-compute the column |
| // norm directly. |
| m_colNormsDirect.coeffRef(j) = m_qr.col(j).tail(rows - k - 1).norm(); |
| m_colNormsUpdated.coeffRef(j) = m_colNormsDirect.coeffRef(j); |
| } else { |
| m_colNormsUpdated.coeffRef(j) *= numext::sqrt(temp); |
| } |
| } |
| } |
| } |
| |
| m_colsPermutation.setIdentity(PermIndexType(cols)); |
| for(PermIndexType k = 0; k < size/*m_nonzero_pivots*/; ++k) |
| m_colsPermutation.applyTranspositionOnTheRight(k, PermIndexType(m_colsTranspositions.coeff(k))); |
| |
| m_det_pq = (number_of_transpositions%2) ? -1 : 1; |
| m_isInitialized = true; |
| } |
| |
| #ifndef EIGEN_PARSED_BY_DOXYGEN |
| template<typename _MatrixType> |
| template<typename RhsType, typename DstType> |
| void ColPivHouseholderQR<_MatrixType>::_solve_impl(const RhsType &rhs, DstType &dst) const |
| { |
| eigen_assert(rhs.rows() == rows()); |
| |
| const Index nonzero_pivots = nonzeroPivots(); |
| |
| if(nonzero_pivots == 0) |
| { |
| dst.setZero(); |
| return; |
| } |
| |
| typename RhsType::PlainObject c(rhs); |
| |
| // Note that the matrix Q = H_0^* H_1^*... so its inverse is Q^* = (H_0 H_1 ...)^T |
| c.applyOnTheLeft(householderSequence(m_qr, m_hCoeffs) |
| .setLength(nonzero_pivots) |
| .transpose() |
| ); |
| |
| m_qr.topLeftCorner(nonzero_pivots, nonzero_pivots) |
| .template triangularView<Upper>() |
| .solveInPlace(c.topRows(nonzero_pivots)); |
| |
| for(Index i = 0; i < nonzero_pivots; ++i) dst.row(m_colsPermutation.indices().coeff(i)) = c.row(i); |
| for(Index i = nonzero_pivots; i < cols(); ++i) dst.row(m_colsPermutation.indices().coeff(i)).setZero(); |
| } |
| #endif |
| |
| namespace internal { |
| |
| template<typename DstXprType, typename MatrixType> |
| struct Assignment<DstXprType, Inverse<ColPivHouseholderQR<MatrixType> >, internal::assign_op<typename DstXprType::Scalar,typename ColPivHouseholderQR<MatrixType>::Scalar>, Dense2Dense> |
| { |
| typedef ColPivHouseholderQR<MatrixType> QrType; |
| typedef Inverse<QrType> SrcXprType; |
| static void run(DstXprType &dst, const SrcXprType &src, const internal::assign_op<typename DstXprType::Scalar,typename QrType::Scalar> &) |
| { |
| dst = src.nestedExpression().solve(MatrixType::Identity(src.rows(), src.cols())); |
| } |
| }; |
| |
| } // end namespace internal |
| |
| /** \returns the matrix Q as a sequence of householder transformations. |
| * You can extract the meaningful part only by using: |
| * \code qr.householderQ().setLength(qr.nonzeroPivots()) \endcode*/ |
| template<typename MatrixType> |
| typename ColPivHouseholderQR<MatrixType>::HouseholderSequenceType ColPivHouseholderQR<MatrixType> |
| ::householderQ() const |
| { |
| eigen_assert(m_isInitialized && "ColPivHouseholderQR is not initialized."); |
| return HouseholderSequenceType(m_qr, m_hCoeffs.conjugate()); |
| } |
| |
| /** \return the column-pivoting Householder QR decomposition of \c *this. |
| * |
| * \sa class ColPivHouseholderQR |
| */ |
| template<typename Derived> |
| const ColPivHouseholderQR<typename MatrixBase<Derived>::PlainObject> |
| MatrixBase<Derived>::colPivHouseholderQr() const |
| { |
| return ColPivHouseholderQR<PlainObject>(eval()); |
| } |
| |
| } // end namespace Eigen |
| |
| #endif // EIGEN_COLPIVOTINGHOUSEHOLDERQR_H |
